A. Cruise Narrative: P15N A.1. Highlights WHP Cruise Summary Information WOCE section designations P15N, PR06, PRS1 P15N Expedition designations (EXPOCODES) 18DD9403_1 18DD9403_2 Chief Scientists and their affiliation John Garrett/IOSÝ Howard Freeland/IOS§ Dates (Leg 1) 1994.SEP.06 to 1994.OCT.10 (Leg 2) 1994.OCT.13 to 1994.NOV.10 Ship R/V John P. Tully Ports of Call (Leg 1) Dutch Harbor, Alaska to, HI (Leg 2) Honolulu to Pago Pago, American Samoa Number of stations (Leg 1) 177 (Leg 2) 191 54 N Geographic boundaries of the stations 171 W 123 30 W 15 S Floats and drifters deployed 15 Argos drifters (7 shallow, 8 deep), 1 meteorological Drifter Moorings deployed or recovered 0 ------------------------------------------------------------------------------ John Garrett Howard Freeland Institute of Ocean Sciences Institute of Ocean Sciences P.O. Box 6000 P.O. Box 6000 9860 West Saanich Road 9860 West Saanich Road Sidney, B.C. V8L 4B2 CANADA Sidney, B.C. V8L 4B2 CANADA Phone: 604-363-6574 Phone: 604-363-6590 Fax: 604-363-6479 Fax: 604-363-6746 Email: jfg@ios.bc.ca Email: freelandhj@dfo-mpo.gc.ca A.2 Cruise Summary Information A.2.a Geographic boundaries On September 6, the Tully sailed west from the mouth of Juan de Fuca Strait, along Line PR6. After completing 4 stations en route to Station PRS1, the vessel sailed for Dutch Harbor, Alaska, where it refueled. Section P15N started near Dutch Harbor and continued south along 165 W. At 24 N, we gradually shifted towards the West to coincide with a previous NOAA section and the planned route of P15S. Most of the scientific crew were changed in Honolulu after 35 days at sea. Leg 2 continued from 20 30 N, following a course that moved gradually westward to 168 45 W at 10(N. We remained on this longitude through the equator, then began a second southwestward course at 8 30 S that took us to 170 W at 10 S. At 15 S, Leg 2 ended and the vessel sailed to American Samoa. A.2.b Stations occupied CTD/rosette casts were done at 3 stations along PR6, PRS1 was reoccupied, and 70 CTD/rosette stations along P15N were done during the first leg. Two rosettes were used to collect 3225 samples for onboard analyses of salinity, oxygen, nutrients, CFCs, total CO2 and alkalinity. Additional samples were stored for 13C, 14C, 18O and CH4. Continuous measurements of air and seawater CO2 were taken from the scientific seawater supply (Uncontaminated Sea Water). USW was also sampled for salinity, nutrients and chlorophyll a at almost all cast stations, and each degree of longitude between PRS1 and Dutch Harbor. Tracers were occasionally collected from the USW supply. TABLE 1: STATION LOCATIONS FOR USW -123.500000 48.266700 -165.000300 46.498000 -168.118800 12.496000 -124.002500 48.299800 -164.999700 45.991800 -168.250200 11.996200 -124.500300 48.449800 -165.162700 45.504000 -168.375300 11.493800 -125.011700 48.539300 -164.755700 44.996700 -168.512000 11.006300 -125.546800 48.578200 -164.790200 44.500200 -168.623200 10.499500 -126.000000 48.600000 -164.995200 43.995000 -168.746000 10.006800 -126.333300 48.616700 -165.009300 43.487200 -168.749000 9.494200 -126.665700 48.649200 -164.990000 43.013300 -168.751000 8.996300 -126.171700 48.693300 -164.999200 42.500000 -168.754300 8.501000 -127.686700 48.743300 -164.995200 41.999700 -168.743300 8.001800 -128.666700 48.816700 -164.997200 41.496800 -168.741200 7.493500 -129.165800 48.856200 -165.005800 40.997700 -168.730700 7.002800 -129.662000 48.892700 -165.023300 40.494300 -168.726200 6.503500 -130.166700 48.933300 -165.000000 40.001300 -168.742000 6.001800 -130.661700 48.966700 -164.907200 39.498200 -168.739300 5.478000 -131.664700 49.044000 -165.000300 38.999200 -168.747300 4.997300 -132.664500 49.122500 -164.998300 38.504800 -168.752000 4.484700 -133.659200 49.200000 -165.003300 37.998300 -168.750200 4.007200 -134.669700 49.283700 -165.001800 37.501800 -168.747700 3.496500 -135.670000 49.350000 -164.999300 36.998000 -168.760000 3.004200 -136.661500 49.415300 -165.006200 36.504700 -168.755700 2.523300 -137.666700 49.650700 -165.002000 35.998000 -168.750300 2.010200 -138.667200 49.566500 -165.004200 35.495000 -168.762200 1.521500 -139.666700 49.633000 -164.995300 35.000800 -168.753200 1.009300 -140.662700 49.701200 -165.000800 34.514700 -168.760700 0.489000 -141.669500 49.767000 -164.993800 34.001300 -168.750700 -0.003200 -142.658300 49.835000 -165.000200 33.496300 -168.752500 -0.510800 -143.603200 50.000000 -165.014500 32.995300 -168.747800 -1.011800 -144.303700 50.001200 -164.995800 32.505000 -168.750700 -1.506800 -144.984500 50.003000 -164.995700 31.997700 -168.742800 -2.010300 -146.009200 50.206300 -165.006000 31.503200 -168.749000 -2.506800 -147.003500 50.401000 -165.006500 31.003700 -168.757000 -3.003300 -148.009500 50.596000 -165.000700 30.503200 -168.741200 -3.496300 -149.003800 50.786500 -164.984300 30.006700 -168.754800 -3.997800 -150.008300 50.979700 -164.994500 29.504500 -168.742200 -4.489200 -151.218300 51.208300 -164.994200 29.001800 -168.752800 -5.004700 -152.007300 51.359700 -165.000800 28.503700 -168.755200 -5.503800 -153.007000 51.550000 -164.998700 27.999800 -168.759200 -6.018000 -154.061500 51.748200 -164.974300 27.512700 -168.755800 -6.503800 -155.000800 51.924500 -164.994200 27.008500 -168.746000 -7.013000 -156.001500 52.112200 -165.001500 26.499200 -168.747800 -7.500500 -157.000000 52.295500 -165.005800 25.995000 -168.747200 -8.008300 -158.021700 52.488300 -164.996500 25.505000 -168.747200 -8.503500 -159.000200 52.666800 -164.998500 25.005300 -169.000200 -9.003500 -160.117800 52.874800 -165.000800 24.498200 -169.004200 -9.507300 -161.128300 53.041700 -164.997000 23.995200 -169.501300 -10.002300 -162.024200 53.183000 -165.317700 23.504800 -170.015500 -10.498200 -163.000200 53.286800 -165.463200 22.917000 -169.997500 -11.004300 -164.000800 53.394300 -165.567500 22.500700 -170.000000 -11.506500 -164.998300 53.640800 -165.703200 21.986800 -170.494200 -11.999000 -164.989500 53.920700 -165.994700 20.899200 -169.991500 -12.503800 -164.989300 53.744700 -158.548000 21.178300 -169.988500 -13.019000 -164.995700 53.500300 -166.086200 20.508800 -169.995300 -13.498800 -165.015000 53.249000 -166.189300 20.016700 -169.995500 -14.007200 -165.003700 52.998200 -166.317200 19.502200 -169.998300 -14.497500 -165.003000 52.739800 -166.439200 19.002500 -169.999500 -15.001300 -165.495700 52.238000 -166.691000 18.001500 -165.141700 51.358300 -166.843200 17.479700 -164.990800 50.967200 -166.994300 16.970500 -164.993200 50.499000 -167.108200 16.494800 -165.003000 50.000300 -167.228200 15.993000 -164.999000 49.493500 -167.349800 15.498300 -165.007300 49.004200 -167.496500 14.998800 -165.000000 48.500200 -167.616300 14.494800 -164.999300 47.999500 -167.750200 13.976200 -164.991500 47.503800 -167.871200 13.493000 -164.995500 47.012700 -167.982800 13.000300 A.2.c Floats and drifters deployed At 4 stations, a total of 15 Argos drifters, 7 shallow (20 m drogues) and 8 deep (120 m drogues), were deployed. A single meteorological drifter was deployed for Department of the Environment near 47 N. About 2 dozen wine bottles with postcards inside were deployed at locations selected by a local school class. A.2.d Moorings deployed or recovered No moorings deployed or recovered A.3 List of Principal Investigators TABLE 2: Principal Investigators Principal Investigator Parameters Institution ------------------------------------------------------ Howard Freeland Climate change, XBTs, ADCP IOS C.S. Wong Climate chemistry IOS TCO2, AT, CFCs, 13C, 14C, 18O, underway pCO2 Ron Perkin Physical measurements IOS CTD, salinity Frank Whitney Chemical measurements IOS Oxygen and nutrients, chlorophyll a, meteorology, bathymetry, thermosalinograph ------------------------------------------------------ A.4 Scientific Programme and Methods Features such as the Alaska Stream, sub-arctic front, 2200 m silicate maximum (37 to 43 N), shallow oxygen minimum north of the equator, equatorial upwelling, flow of Antarctic water through the Samoan Gap, etc. are readily identified in this data set. Surface waters in the subarctic region of the Pacific are evidently a strong sink for CO2 in September. Our deep ocean winch, rosette/CTD and heave compensation equipment worked very well to 6000 m, the first test it has had below 4200 m. Sampling from the Tully was equally successful. The ship was able to hold station in 40 knot winds, and aft deck sampling proved comfortable and safe in most conditions. Sampling was suspended whenever the rosette unweighted excessively, as recorded on a load sensor mounted between the rosette and cable. A.5 Major Problems and Goals not Achieved Several stations were omitted due to high winds (reaching 70 knots), and CTD casts only were attempted at another 12 stations in marginal conditions. Thus there is a gap in the hydrographic sampling between 47 N and 43 30 N. Sampling intervals were spaced to 250 or 500 m below 3000 m at many stations, allowing us to save time by carrying out only a single rosette cast. This spacing should result in negligible loss of information, since there is little structure in North Pacific deep waters. Our deep ocean winch was damaged beyond repair following a cast at 10 S. Subsequent sampling was restricted to a maximum depth of 3800 m. CFC instrumentation caused us continual grief, although about 75% of the stations were successfully analyzed. We had to return to Honolulu to pick up a replacement Gas Chromatograph at the beginning of Leg 2, costing us 3 days of ship time. There were some difficulties encountered throughout the cruise that hampered obtaining optimal results for CFC-11 and CFC-12. A problem with the consistency of the quality of the carrier gas meant having to subtract higher than normal stripper blanks. The results of stations 83 to 97 may show zero at the 300 to 400 m depth because the threshold was initially set as per the 5890 GC program. This was modified for later stations in order to have very small peaks integrated. Thus these zero values may be a factor of threshold setting rather than a complete absence of CFCs. During some of the earlier stations we encountered samples affected by some sort of interference. This resulted in the F11 peak being split or at other times summed, usually in the fifty meter sample. Neither using the split value or a summed value seemed to give a reasonable result so these samples were flagged as questionable or bad. This problem was also encountered on the first leg of the cruise. Phosphate samples were frequently contaminated during the second half of the first leg. A nitrate reagent containing phosphoric acid was spilt on September 30 when Stations W044, W045, and W046 were analyzed. On October 1 it was noted in the nutrient log that the crew were washing the deck with soap - Stations W047, W048 and W049 were analyzed on this day. Our water demineralizing system failed during Leg 2, which forced us to use low nutrient sea water 1) to establish a baseline during analyses, and 2) for the preparation of standards. Each day, a sample of 3.2% NaCl in double run Milli-Q water was analyzed to assess the zero concentrations for each nutrient. Silicate and phosphate in wash water typically was 2 and 0.2 mM higher than the clean salt water solution. All data have been corrected for this baseline offset. LNSW was also used as a rinse after acid cleaning. The nitrite line developed a problem with crystal buildup at Station W123 and continued to the end of the cruise. This resulted in higher than expected values for deep samples and all data for Stations W123 - W137 has been labelled data quality 3 for both nitrite and nitrate. Nitrate data is questionable due to the doubtful subtraction of 0.1 to 0.3 umol/kg nitrite. A.6 Other Incidents of Note A.7 List of Cruise Participants TABLE 3: Cruise Participants Individual Responsibility Institution ------------------------------------------------------------------ Leg 1: John Garrett chief scientist IOS Frank Whitney coordinator, hydro. data IOS Dario Stucchi CTD data processing IOS John Love electronics, sampling, salinity IOS Bernard Minkley sampling, salinity IOS Reg Bigham sampling IOS Tim Soutar sampling IOS Ron Bellegay sampling IOS Valerie Knight carbonates IOS Galina Pavlova carbonates POI Linda White nutrients IOS Andrei Andreev nutrients POI Pavel Tishchenko CFCs POI Ruslan Chichkin CFCs POI Leo Rebele CFCs student Sarah Thornton Oxygen student Marie Robert sampling IOS Louise Timmermans sampling student Mary-Beth Derube sampling IOS Leg 2: Howard Freeland chief scientist IOS Ron Perkin CTD data IOS Bernard Minkley hydro data IOS John Love electronics, sampling, salinity IOS Reg Bigham sampling IOS Neil Sutherland sampling IOS Dennis Sinnott sampling IOS Hugh Maclean sampling UBC Keith Johnson carbonates IOS Marty Davelaar carbonates IOS Janet Barwell-Clarke nutrients IOS Mary OBrien nutrients IOS Wendy Richardson CFCs IOS Carol Stewart CFCs IOS Tracy Feeney CFCs student Bob Wilson Oxygen IOS Taimi Mulder sampling student Rhiannon Johnson sampling student Robin Brown sampling IOS ------------------------------------------------------------------ Abbreviations: IOS Institute of Ocean Sciences, Sidney, B.C. Canada POI Pacific Oceanological Institute, Vladivostock, Russia UBC University of British Columbia Vancouver, B.C. Canada B. Underway Measurements B.1 Navigation and bathymetry A SAIL (Standard ASCII Interface Loop) system onboard ship poles several sensors at 2 min intervals. Data is stored on a micro computer and is subsequently processed in a format that is accessible for general use. Ships speed, heading, and position plus ocean depth are logged. B.2 Acoustic Doppler Current Profiler (ADCP) A hull mounted current profiler logged upper layer currents every 5 min throughout the cruise. B.3 Thermosalinograph and underway dissolved oxygen, etc Temperature and conductivity sensors are installed near the intake of a sea water line that is used as a scientific supply in the laboratory. Data is logged on SAIL. Uncontaminated Sea Water (USW) was continuously pumped to the laboratory and used for half hourly measurements of pCO2, continuous fluorometry (chlorophyll a) and discrete sampling at stations. An infrared analyzer was used to measure air, sea water and standard CO2 concentrations every 30 minutes throughout the cruise. Sea water was equilibrated within a trapped air space to provide samples for measurements of pCO2 in surface sea water (DOE 1994). Chlorophyll a samples were collected from the USW supply at most stations, and filtered through Whatman GF/F filters. Samples were then frozen for transport back to IOS. B.4 XBT and XCTD XBTs (Type T-5, 1830 m) were used at several stations when bad weather prevented use of CTDs. B.5 Meteorological observations Logged on SAIL are wind speed and atmospheric pressure. B.6 Atmospheric chemistry C. Hydrographic Measurements C.1. Water sampling 1. A 23 bottle rosette with a Guildline Model 8737 CTD was our primary sampling system (Niskin bottles numbers 1 to 23). 2. An 11 bottle rosette with a Guildline 8705 CTD was used for shallow casts (Niskin bottles number S1 to S11). Water samples were collected from rosettes by both CFC analysts (Freons only) and sampling teams. Samples were drawn in the order CFCs, oxygen, carbonate suite (TCO2, alkalinity, 13C, 14C) and methane, then nutrients, salinity and 18O in any order. CFC samples were drawn into 100 ml glass syringes that were thoroughly rinsed in a continuous stream of sample. CFC samplers checked each Niskin bottle for leaking by pushing in the sample spigot before opening the air vent. Gas samples were drawn through amber or Tygon tubing and were all allowed to overflow from one to two volumes. Carbonate samples were poisoned with 200 ml of saturated HgCl2 solution per 250 ml. Methane samples were drawn through amber tubing into glass bottles. Rubber septa with syringe needles piercing their centers, were used to eliminate air from the samples. Septa were crimp sealed in place and samples were refrigerated. Other sample containers were rinsed 3 times and filled as required. Nutrient samples were refrigerated until analysis. Salinity samples were warmed to lab temperature before being analyzed. 180 samples were tightly stoppered and refrigerated. Standard Deviation of Pairs (Sp) Standard Deviations of Pairs (Sp) were calculated from replicates drawn from Niskin bottles tripped within 2.3 db of each other using the following formula. Sp - {(summation of d**2)/2k}**0.5 where d - differences between pairs and k - number of pairs. Using this as a measure of precision includes all discrepancies introduced by leaking water samplers, sample collection, sample storage and analysis. TABLE 4: Standard Deviation of Pairs (Sp) Parameter Range Sp k ------------------------------------------------ Salinity (PSS-78) 33.576 - 35.923 0.003 46 Oxygen (umol/kg) 20.86 - 203.41 1.02 45 Silicate (umol/kg) 0.02 - 149.8 0.34 46 Nitrate (umol/kg) 0 - 42.9 0.11 44 Nitrite (umol/kg) 0 - 1.406 0.008 46 Phosphate (umol/kg) 0.04 - 3.13 0.02 46 CFC-11 (pmol/kg) 0.415 - 2.587 0.076 11 CFC-12 (pmol/kg) 0.263 - 1.359 0.040 11 ------------------------------------------------ C.2 WOCE Line P15N: CTD Calibrations The P15N data was calibrated and processed to the stage of one metre average files using laboratory calibrations done before and after the cruise. The data were then examined for changes which may have occurred during the cruise, consistency between the three CTDís used and agreement with bottle salinities. The findings are given below. Instruments The three CTDís used were all Guildline CTDís, the primary instrument being the WOCE model (WOCE CTD) which was used for most of the deep casts using the 24 bottle rosette. The 12 bottle rosette used for shallow casts was equipped with a standard Guildline Digital CTD (OP CTD sn 58483). In weather too rough for launching a rosette, a modified Guildline Digital CTD was used (CTD6). WOCE CTD, Guildline Model 8737 , SN 59901 This CTD was used for most of the casts in this cruise usually mounted in a bottle slot on a custom made 24 bottle rosette. It was interfaced to a GO pylon which triggered the 10-liter bottles in the 23 remaining slots; data gathering was not interrupted by the bottle triggers. Sensor data was digitally compensated for the effects of the electronics temperature which was monitored at all times. Additional sensors were a load cell giving the wire stress at the Rosette and two thermistor temperature sensors logged every half second. Pressure The Paros pressure sensor model 410K-101, Serial No. 50395 was calibrated on May 1, 1994 against a factory calibrated reference Paros pressure sensor. The correction was -1 +/-1 dbar for the entire range with no hysteresis. No correction was applied. Temperature Temperature calibrations are referenced to the triple point of water(.01 C) and the triple point of phenoxybenzene (26.868 C, IPTS-68, National Physical Laboratory, UK). Interpolation was done by a set of six reference thermistors calibrated at the National Research Council of Canadaís temperature standards lab. The thermistors were offset to match their calibrations at the triple point of water. Slope changes to match the high temperature triple point amounted to a change of -.0019 C at 30 C, the highest temperature measured. (Note: all WOCE data is converted to ITS-90) The main temperature sensor is a copper resistance thermometer, SN 51429. Through three years of use this sensor has been stable +/-.0065ƒC with no slope correction necessary. It was calibrated in May, 1994 giving an offset of -.005C and in Jan., 1995 giving an offset of -.0065ƒC. Calibration shifts were tracked by two complementary calibration thermistors using a separate housing, interfacing and digitizing circuitry and scanned every half second. These sensors are slower than the main sensor and were corrected for a 3 second time constant. Data from low gradient regions, deeper than 2000 m, were used to track any calibration shifts which occurred during the cruise. Because of factory changes in the internal circuitry done between the pre-cruise calibration and the start of the cruise, the post-cruise calibration was used and changes to the main temperature sensor were back-tracked using the calibration thermistors. Six digital SIS reversing thermometers were used on the rosette as an additional check. Of these, one failed to track the other sensors and others showed a tendency to drift to lower temperature. Three, #451, #647 and #679 were chosen by their consistency with each other and the reference thermistors and the fact that they were used in low gradient regions below 2000 m where time constant problems were minimal. Calibrations on the reversing thermometers were done in March ë94. Temperature Corrections Using the post-cruise calibration, new corrections for internal electronics temperature were computed for temperature(Tmain), conductivity and the two reference thermistors (th1 and th2). Calibration constants were determined as follows and used to re-process the data: TABLE 5: Calibration Coefficients ------------------------------------------------------------- CONDUCTIVITY CORRECTION FACTORS FOR P AND T g#(0) - -.0000032 g#(1) - .0000001 TEMPERATURE U(0) - -5.91775 - .0065 U(1) - 7.7834E-05 / 2 U(2) - 1.92916E-13 / 4 CONDUCTIVITY V(0) - -.000519# V(1) - 1.69181E-06 V(2) - 0 cELLK - 1! ëCELL CONSTANT TO BE ADJUSTED FOR BOTTLE SALINITIES Nref - rawdata&(13) - 3956 ëNref IS PROPORTIONAL TO ELECTRONICS TEMP. Nc& - rawdata& (0) + Nref * (-.472) Conductivity Nt& - rawdata& (1) + Nref * 1.24 Temperature TEMPERATURE - calctemp(U(0), U(1), U(2), Nt&) conductivity - calccond(V(0),V(1),V(2),Nc&)*(1+g#(0)*TEMPERATURE+ g#(1)*PRESSURE) * cELLK therm1raw - rawdata&(8) + (-.0545) * TREF therm2raw - rawdata&(9) + (-.04) * TREF 'calculate thermistor resistance(ohms) according to post P15n cal. rt1 - 3591.57 - 6.540890000000001D-02 * therm1raw rt2 - 3628.768 - .0766183# * therm2raw th1 - thermtemp(.00101711365#, .000294395858#, .00000015683113#, rt1, th1off) th2 - thermtemp(.00104554083#, .000290301739#, .00000015888418#, rt2, th2off) '3 sec. slower thermistors. So with a +ve rate of change, they read colder. thermdelt - 3 * tgrad 'look back by one time const. diff. 'the thermistors are -.13 m below the Copper T sensor. IF dz > 0 THEN ZOFF - -.13 ELSE ZOFF - .13 IF ABS(dz) > .14 THEN thermdeld - -ZOFF * tgrad * dt / dz ELSE thermdeld - 0 'total correction to thermistors is: thcorr - thermdelt + thermdeld tcomp - TEMPERATURE - ((th1 + th2) / 2 + thcorr) PRINT #3, USING fprintf$; rawdata&(41); PRESSURE; TEMPERATURE; SALINITY; conductivity; th1 + thcorr; th2 + thcorr; TREF; temp; TCOMP; Frame(KK) -------------------------------------------------------------------------------- In a typical cast starting at close to 30C and ending close to 1ƒC, the internal temperature monitor, Nref, will change by about 350 units. Over this range, corrections are as follows: Tmain: (350*1.24*7.7e-5/2) - .016ƒC Cond.: (-.472*350*1.69e-6) - -.000279 (-.0159 in salinity) Th1: (-.545*350*.065) - 12.3 ohms (.061 ƒC in temperature) Comparisons for calibration purposes were generally made in water deeper than 2000 m where changes in Nref are much smaller than 350 units, typically 30 units. Using the re-processed data, the average difference between th1 and Tmain were computed for each cast only for data below 2000 dbars. For the last 26 casts, th1 and Tmain agreed within .001C so the post cruise calibration was deemed valid for these casts. Systematic changes in the comparison through the course of the cruise were attributed to the main sensor because of its more sensitive construction. However, it was noticed that the correction was different for down and up casts by about .001ƒC and different by about .0049ƒC depending on whether or not the load cell used to monitor line stress at the Rosette was attached. These offsets were very stable and consistent. Removal of the load cell also removed the difference between down and up casts and resulted in good agreement between the CTD sensors and reversing thermometers. Although this effect has not been fully explained, tests in the shop show that there appears to be some interference between the sensors and the load cell. Work is proceeding to eliminate it but, for the purposes of this cruise, a compensating offset was applied. Although Thermistor 2 was in good agreement(+/- 0.02 C) with thermistor 1, it did not fit the calibration bath thermistors or the main sensor as well as thermistor 1. So Thermistor 1 was used to track calibration shifts during the cruise. Its temperatures were offset to compensate for the .0049 C shift on casts with the load cell, the majority of the data. The temperatures measured by the reversing thermometers were corrected according to their calibrations of March, 1994 and compared with Tmain (corrected for high and low triple points). There was a great deal of scatter in the comparisons so once again comparisons were limited to depths below 2000 m and three of the sensors were eliminated because of apparent drift problems or the depth limitation already mentioned. The remaining three (#451, #647 and #679) were in good agreement with the corrections determined by Thermistor 1 although #647 had apparently drifted by about .003C by the end of the cruise. A spot check on #647 a year later showed a change of .005C at low temperature. In general, these sensors are not as stable as they should be and some further work is being done to remove solder flux from the sensor areas. More frequent calibrations are also necessary. Conductivity The conductivity sensor is a 4-electrode Guildline Pyrex glass sensor. Conductivity data was corrected for the effects of pressure and temperature on Pyrex glass(Bennett, A. S., 1976, Conversion of in situ measurements of conductivity and salinity., D.S.R., vol. 23, pp. 157 to 165.); conductivities derived from bottle salinities were used to correct the cell constant as described below. Calibration samples were drawn from the 10-liter Niskin bottles into Pyrex bottles and analyzed within a few days on board. Bottle salinities were determined using a Guildline Portasal salinometer referenced to Batch P121 standard seawater. The internal precision of the Portasal exceeds +/-.001 C in salinity. Duplicate samples to test the precision of the procedure agreed with in .002 C. Other sources of error include sampling errors and mis-triggers and are thought to be either small or to have been corrected by visual inspection of outliers in the resulting salinity and chemical data. After determining the temperature corrections above and recomputing salinity, comparisons were made at the bottle points. Upcast and downcast salinities were compared to bottle salinities and systematic pressure-dependent trends were removed. For the downcast data, an additional correction of P*(3E-8) was added to the conductivity to account for a small pressure dependency. For the upcasts, the trend was removed with a correction of P*(-1E-8). Possible causes of this effect are errors in the compensation for internal temperature, possibly due to thermal transients which would be stronger on the downcast. In order to compare with bottles collected on the upcast, down cast salinities were interpolated to the matching upcast temperature to compensate for the vertical movement caused by internal waves during the roughly 3.4 hours of a cast. This was done by comparing temperatures in the appropriate depth range and offsetting salinity to the bottle temperature using the local TS slope estimated over a 10 dbar range. A careful processing, shown in the table below, of an example cast, #97, produced salinity agreement ±.002ƒC from 5826 dbar to 200 dbar. Higher errors near the surface are expected because of the instability of the water column, including the TS correlation. Table 6. Hand processing of a typical down cast removes the effect of internal waves by interpolating to the temperature at which the bottle was triggered on the up cast. Agreement between bottle salinity and CTD salinity is good from 200 dbar down. P15N Cast 97 BOTTLE Depts up cast Down Salinity data cast data Error UP P Cruise T Corr.T T(P-5) T(P+5) S(P-5) S(P+5) Sinterp Sbott Bott-Interp ------------------------------------------------------------------------------------------- 11.56 23.0931 23.0994 23.07697 23.07167 34.59999 34.57936 34.68732 34.5555 -0.13182 49.02 16.0177 16.024 16.48648 15.08266 34.46396 34.44395 34.45737 34.3999 -0.05747 100.18 12.8362 12.8425 12.8824 12.66911 34.38542 34.36216 34.38107 34.3713 -0.00977 199.96 10.8816 10.8879 11.1023 10.90042 34.21864 34.18872 34.18687 34.1845 -0.00237 299.91 10.0152 10.0215 10.20157 10.08747 34.19784 34.1877 34.18183 34.1822 0.000369 399.98 8.6104 8.6167 8.464675 8.272387 34.08092 34.06794 34.09119 34.0905 -0.00069 601.26 5.4378 5.4441 5.278873 5.119783 34.00744 34.01951 33.99491 33.998 0.003088 799.94 4.0703 4.0766 4.089046 4.046349 34.16306 34.17121 34.16544 34.1641 -0.00134 1000.49 3.4009 3.4072 3.405389 3.37939 34.29684 34.30184 34.29649 34.294 -0.00249 1250.35 2.8679 2.8742 2.842024 2.819325 34.42956 34.43389 34.42342 34.421 -0.00242 1499.69 2.4731 2.4794 2.461347 2.439049 34.51694 34.51789 34.51618 34.5127 -0.00348 1750.54 2.1319 2.1382 2.145267 2.136668 34.56895 34.57033 34.57008 34.5699 -0.00018 1999.78 1.9248 1.9311 1.92798 1.919581 34.60301 34.60434 34.60251 34.6014 -0.00111 2250.18 1.7762 1.7825 1.77219 1.76839 34.62828 34.62888 34.62667 34.6259 -0.00077 2499.08 1.6601 1.6664 1.663897 1.661197 34.64509 34.64527 34.64493 34.6433 -0.00163 2748.77 1.5847 1.591 1.594001 1.590901 34.65649 34.65697 34.65695 34.6582 0.001246 2999.49 1.5395 1.5458 1.543304 1.542004 34.66485 34.66508 34.66443 34.6643 -0.00013 3500.81 1.4817 1.488 1.489108 1.487808 34.67585 34.67623 34.67617 34.6767 0.000525 3998.45 1.4721 1.4784 1.479308 1.478308 34.68221 34.68241 34.68239 34.6818 -0.00059 4499.44 1.4903 1.4966 1.495207 1.495507 34.68624 34.68627 34.68638 34.686 -0.00038 4999.78 1.5273 1.5336 1.532005 1.532705 34.68889 34.68897 34.68908 34.6884 -0.00068 5499.6 1.5753 1.5816 1.580302 1.581402 34.69106 34.69094 34.69092 34.691 8.35E-05 5826.5 1.6071 1.6134 1.6129 1.6115 34.6914 34.6914 34.6914 34.6911 -0.0003 ----------------------------------------------------------------------------------------- Bulk processing of the data using local TS slopes estimated over 40 dbars produced a similar improvement although not quite as much as the detailed processing of cast #97. Below is a plot of the cell constants computed from each bottle at or below 2000 dbars for the whole cruise. These cell constants were averaged for each cast in order to compensate for the small systematic and random differences between the casts. Differences from this average cell constant were computed for each bottle and are shown plotted below on the same graph. This CTD was used as a backup to the WOCE CTD and is also equipped with a Paros sensor for accurate pressure determination. It was used by itself when the weather was too rough to safely launch the Rosette so there are not many bottle samples to use for comparison. However, at Station W108, it was used in a cast to 5000 m with a set of 11 bottles from 1750 dbar to 5000 dbar. These bottles were used to determine the cell constant. In addition to the comparisons to the on-board thermistors, the temperatures were compared to the adjacent casts at stations W107 and W109 to verify the temperature calibration (see the section on temperature). Finally, the TS properties of CTD6 casts taken near the end of the cruise were compared with the set of corrected WOCE CTD temperatures and their matching bottle salinities as shown below in the section on conductivity. TABLE 7 The initial calibration on which these changes take effect is given below: _____________________________________________________________________________ *CALIBRATION $TABLE: RAW CHANNELS !Name Units Fmla Pad Coefficients !------------------------- -------------- -- ---- ------------------------ Time_stamp none 10 n/a (0 1) Temperature:Analog_Probe n/a 10 n/a (0 1) Voltage:reference n/a 0 " Voltage:reference:2 n/a 0 " Temperature 'DEG C (ITS68)' 10 -9 (0 1) Conductivity_ratio n/a 63 -9 (0 1) Pressure DBAR 10 -9 (-10 1) Temperature:thermistor1 n/a 34 -9 (4722.61 0.203168 0.1051772E-02 0.2894819E-03 0.155711E-06 0) Temperature:thermistor2 n/a 34 -9 (4826.07 0.2058 0.1027592E-02 0.2916148E-03 0.1542955E-06 0) Temperature:digiquartz n/a 10 -9 (0 1) Temperature:2 n/a 0 -9 Transmissivity n/a 0 -9 Conductivity_ratio:2 n/a 0 -9 $END _____________________________________________________________________________ Pressure Pressure The Paros pressure sensor model 410K-101, Serial No. 50500 was calibrated before the cruise on Aug. 26, 1994. At 22ƒC, the pressure correction was -3 dbar and at 3 C, the pressure correction was 0 dbar. There was no hysteresis. No correction was applied beyond the -10 dbar correction from absolute to gauge pressure. Temperature The main temperature sensor is a copper resistance thermometer. It is complemented by two calibration thermistors in a separate housing using separate interfacing circuitry. These sensors are slower than the main sensor and serve to track any calibration shifts which may occur during the cruise. CTD6 agreed well with its second thermistor +/-.002ƒC but not with the first which read .01C high. Thermistor 2 indicated an average correction of -.002 C. Below is the temperature comparison at Stn. 108 which shows good agreement with the WOCE CTD values at adjacent stations (these were later corrected up by .001 C). At depths near 4000 dbar, the CTD6 temperatures seem to be a bit too high. Application of the above correction of -.002 C would bring the three casts into good agreement. Therefore, CTD6 temperatures were corrected by -.002 C. CTD6 was used near the end of the cruise without the benefit of bottle salinities. Comparison with bottles collected on other casts done with the WOCE CTD. The effect of applying the cell constant of .99984 results in good agreement in TS space between the two data sources. Ocean Physics CTD (OP CTD) This CTD was used mainly for casts with the 12-bottle Rosette to depths not exceeding 1500 dbar. Its main function was to provide temperature and pressure data for the bottles since each station was covered by full depth profile by one of the other CTDís. Comparisons in the upper 1500 m of the water column with the other CTDís showed a great deal of scatter due to water column variability so a lowered accuracy is claimed for this data. The calibration originally used was: Table 8: More Calibration coefficients _____________________________________________________________________________ *CALIBRATION $TABLE: RAW CHANNELS ! Name Units Fmla Pad Coefficients ! -------------------- --------------- ---- ------ ------------ Pressure DBAR 10 -99 (0 3000) Temperature 'DEG C (ITS68)' 10 -99 (0.47653E-01 0.99872) Conductivity_Ratio n/a 10 -99 (0.62E-03 0.99898) $END ______________________________________________________________________________ Pressure The pressure sensor was calibrated before the cruise and during the cruise with a reversing pressure sensor. Of 25 calibrations, the average offset determined by the reversing pressure sensor was -4.6 dbar with a standard deviation of 2.1 dbar. The pressures for this CTD were therefore offset by -4.6 dbar. Temperature The main temperature sensor is a copper resistance thermometer. Comparison with reversing thermometer #679 and #647 gave a mean correction of .0076C. The scatter on temperature comparisons as a result of water column variability suggests an accuracy of .007 for these data. TABLE 9. In-Situ calibrations for OP CTD (sn 58483) REVERSING SENSORS Btl CTD CTD Bottle Sensor Sensor # Press. Temp. Salinity Trev Prev Trev Trev-Tctd Prev-Pctd (dbar) (°C) (psu) (°C) (dbar) (°C) (°C) (dbar) ---------------------------------------------------------------------- 103 1002.97 2.994 34.3459 2.994 996.4 2.99924 0.00524545 -6.57 513 603.15 4.311 34.101 4.313 599 4.31847 0.00747693 -4.15 593 594.83 4.574 34.0393 4.571 593.3 4.57652 0.00252221 -1.53 671 496.05 6.363 33.9955 6.482 487 6.48785 outlier -9.05 830 603 5.363 34.0015 5.372 598.2 5.37766 0.01466279 -4.8 910 598.42 6.124 33.9983 6.109 595.3 6.11479 -0.00920787 -3.12 944 600.3 6.284 33.9929 6.31 595.6 6.31582 outlier -4.7 1001 599.02 5.899 33.9925 5.913 594.1 5.91875 0.01975773 -4.92 1058 795.6 4.201 34.1374 4.205 790.3 4.21045 0.00945798 -5.3 1115 799.5 4.31 34.1314 4.314 796.8 4.31947 0.00947711 -2.7 1172 601.88 6.306 34.0223 6.317 596.5 6.32863 0.01682863 -5.38 1229 1002.75 3.813 34.3584 3.822 997.3 3.82739 0.01439076 -5.45 1295 605.85 6.795 34.043 6.778 603.2 6.78390 -0.01109046 -2.65 2686 1000.35 4.667 34.5512 4.664 995.9 4.67579 0.00879269 -4.45 ---------------------------------------------------------------------- averages 0.0074 -4.6 Conductivity As previously mentioned, bottle comparisons in the upper 1000 m produced noisy data. However, comparison of downcasts with corresponding up cast bottle data resulted in the following data for determining the cell constant for this CTD. The low value for the first cast, which was at Stn. P, was to some extent due to temporal variation because the upcast gave values near 1.0000. Based on these findings and accounting for the compression of the conductivity cell, the cell constant was set at 1.0001 and the accuracy of the salinity determinations was downgraded to .01, equivalent to .00025 in the cell constant. SUMMARY Processing was done according to the calibrations constants determined during the cruise. Salinity accuracy is estimated below for each CTD except in regions of the profiles where strong temperature and conductivity gradients result in errors due to sensor mismatches. Salinity spikes have been removed by hand in some profiles. Using bottle samples, on-board thermistors and reversing temperature and pressure sensors additional calibration constants were determined as follows: WOCE CTD No change to pressure. The WOCE CTD was initially calibrated with the post-cruise calibration of (offset, slope) - (-.0015, .999938). To account for changes which occurred during the cruise the temperature offsets listed in the following table were applied. Down cast salinities were matched to corresponding bottle salinities with a separate cell constant determined for each rosette cast (see table below). Agreement to a standard deviation of less than .001 in salinity with bottle samples below the 2000 dbar horizon was achieved. Temperature accuracy is estimated at .002C , salinity at .002. CTD6 No pressure correction. Temperature correction: -.002 C. Cell constant: .99984 Temperature accuracy is estimated to be .002 C and salinity accuracy to be .005. OP CTD (58483) Pressure correction: -4.6 dbar Temperature correction: .0074 C. Cell constant: 1.0002 Temperature accuracy is estimated to be .007 C and salinity accuracy to be.01 Calibration instructions for the WOCE CTD. Processing of .1ma files. The .1ma files have been edited to remove spikes, therefore, salinity cannot be recomputed from corrected temperatures and conductivities derived from the raw files. However, the conductivity has not been corrected for the pressure and temperature effects on the conductivity cell. In addition, three calibration steps are necessary to correct the data: … a pressure-dependent conductivity correction … a temperature offset and slope … a cell constant to produce agreement with bottle salinities. Since corrections are to be applied to the conductivity, it is easiest to generate a new conductivity using the despiked salinity and the SAL78 routine. The other alternative is to compute a salinity correction but because of the interaction of the temperature and conductivity corrections, this would be much harder and may lead to errors. The conductivity cell correction can be combined with the pressure-dependent conductivity correction: Rcorr - R1ma(1 + P*(1.3E-7) + T*(-3.2E-6)) The temperature offset should be applied in two steps: 1. add .004C to all WOCE CTD casts after 94030219.1ma to remove the old change in offset. This amounts to resetting the A0 in the temperature polynomial to -5.92425 for all casts. 2. add the temperature offset in the list supplied to each cast and apply slope of .999938 to all temperatures to compensate for high temperature triple point correction on the bath thermistors. The offset correction was included in the A0 figure quoted above. Apply the cell constant in the supplied list to the conductivity. Rfinal - Rcorr * Cellk Recompute salinity using the the final values of R, T and P. TABLE 10. WOCE CTD Corrections Relative to the post-cruise consec celk Temp |consec celk Temp |consec celk Temp # _avg offset | # _avg offset | # _avg offset --- -------- -------- | --- --------- ---------| --- -------- ------- 1 0.999874 0.008967 | 126 0.99995 0.005225 | 251 0.999948 -0.00092 2 0.999874 0.008967 | 127 0.999942 0.00733 | 252 0.999915 0.001212 3 1.000084 0.008967 | 128 0.999942 0.005769 | 253 0.999915 -0.00103 4 1.000084 0.008967 | 129 0.999942 0.005769 | 254 0.999915 -0.00103 5 0.999975 0.008967 | 130 0.999942 0.005769 | 255 0.999915 -0.00103 6 0.999975 0.008967 | 131 0.999947 0.007092 | 256 0.999923 0.000493 7 0.999952 0.007873 | 132 0.999947 0.005238 | 257 0.999923 -0.00081 8 0.999952 0.008565 | 133 0.999976 0.006334 | 258 0.99991 0.000465 9 0.999952 0.007528 | 134 0.999976 0.005268 | 259 0.99991 -0.00077 10 0.999952 0.007528 | 135 0.999976 0.005268 | 260 0.99991 -0.00077 11 0.999952 0.007528 | 136 0.999976 0.005268 | 261 0.99991 -0.00077 12 0.999952 0.007528 | 137 0.999959 0.006557 | 262 0.99991 -0.00077 13 0.999952 0.007528 | 138 0.999959 0.00538 | 263 0.999938 0.001093 14 0.99998 0.007528 | 139 0.999959 0.00538 | 264 0.999938 -0.00095 15 0.99998 0.008247 | 140 0.999959 0.00538 | 265 0.999952 0.00048 16 0.99998 0.007452 | 141 0.999959 0.00538 | 266 0.999952 -0.0009 17 0.99998 0.007452 | 142 0.999967 0.006914 | 267 0.999952 -0.0009 18 0.99998 0.007452 | 143 0.999967 0.005579 | 268 0.999952 -0.0009 19 0.99998 0.007452 | 144 0.999967 0.005579 | 269 0.999944 0.000918 20 0.99998 0.007452 | 145 0.999967 0.005579 | 270 0.999944 -0.00095 21 0.99998 0.007452 | 146 0.999947 0.006437 | 271 0.999944 0.000918 22 1.000003 0.007452 | 147 0.999947 0.004717 | 272 0.999944 0.000918 23 1.000003 0.007491 | 148 0.999971 0.006279 | 273 0.999944 0.000918 24 1.000003 0.007323 | 149 0.999971 0.004864 | 274 0.999944 0.000918 25 1.000003 0.007323 | 150 0.999908 0.006209 | 275 0.999944 0.000918 26 1.000003 0.007833 | 151 0.999908 0.004681 | 276 0.999944 0.000918 27 0.999915 0.006976 | 152 0.999898 0.006197 | 277 0.999944 0.000918 28 0.999915 0.008049 | 153 0.999898 0.005034 | 278 0.999944 0.000918 29 0.99996 0.006805 | 154 0.999906 0.006135 | 279 0.999963 0.000833 30 0.99996 0.008395 | 155 0.999906 0.004743 | 280 0.999963 -0.00085 31 1.000006 0.00706 | 156 0.999882 0.006066 | 281 0.999948 0.000392 32 1.000006 0.008 | 157 0.999882 0.004782 | 282 0.999948 -0.00138 33 1.000022 0.006856 | 158 0.999913 0.006024 | 283 0.999946 0.000633 34 1.000022 0.007994 | 159 0.999913 0.00525 | 284 0.999946 -0.0015 35 1.000001 0.006858 | 160 0.999964 0.006435 | 285 0.999945 0.000806 36 1.000001 0.008517 | 161 0.999964 0.004984 | 286 0.999945 -0.00101 37 0.999914 0.006794 | 162 0.999988 0.005913 | 287 0.999945 -0.00101 38 0.999914 0.008112 | 163 0.999988 0.004589 | 288 0.999945 -0.00101 39 1.000004 0.007239 | 164 0.999989 0.005864 | 289 0.999933 0.00081 40 1.000004 0.007831 | 165 0.999989 0.004678 | 290 0.999933 -0.0011 41 0.999979 0.007011 | 166 0.999986 0.005753 | 291 0.999962 0.000557 42 0.999979 0.008248 | 167 0.999986 0.004637 | 292 0.999962 -0.00145 43 0.999976 0.007022 | 168 0.999986 0.004637 | 293 0.999949 0.000445 44 0.999976 0.008251 | 169 0.999986 0.004637 | 294 0.999949 0.000445 45 0.999976 0.007333 | 170 0.999946 0.006031 | 295 0.999949 0.000445 46 0.999976 0.007333 | 171 0.999946 0.004525 | 296 0.999949 0.000445 47 0.999976 0.007333 | 172 0.999946 0.004525 | 297 0.999943 0.000126 48 0.999976 0.007333 | 173 0.999946 0.004525 | 298 0.999943 -0.000081 49 0.999976 0.007333 | 174 0.999946 0.004525 | 299 0.999943 -0.000081 50 0.999914 0.007333 | 175 0.999946 0.004525 | 300 0.999943 -0.000081 51 0.999914 0.008126 | 176 0.999946 0.005627 | 301 0.999917 0.000447 52 0.999925 0.006856 | 177 0.999946 0.004717 | 302 0.999917 -0.00127 53 0.999925 0.008557 | 178 0.999946 0.00577 | 303 0.999913 -0.000021 54 0.999958 0.00672 | 179 0.999946 0.004102 | 304 0.999913 -0.00112 55 1.000048 0.008258 | 180 0.999946 0.006606 | 305 0.999913 -0.00112 56 1.000048 0.008069 | 181 0.999946 0.006542 | 306 0.999913 -0.00112 57 1.000048 0.006733 | 182 0.999995 0.006774 | 307 0.999966 0.000217 58 1.000048 0.006733 | 183 0.999995 0.004974 | 308 0.999966 -0.00112 59 1.000048 0.006733 | 184 0.999995 0.004974 | 309 0.999952 0.000131 60 1.000048 0.006733 | 185 0.999995 0.004974 | 310 0.999952 -0.00171 61 0.999981 0.008607 | 186 0.999979 0.006897 | 311 0.999952 -0.00171 62 0.999981 0.007265 | 187 0.999979 0.005886 | 312 0.999952 -0.00171 63 1.000023 0.008451 | 188 0.999979 0.005886 | 313 0.99991 0.000646 64 1.000023 0.007009 | 189 0.999979 0.005886 | 314 0.99991 -0.00092 65 1.000052 0.008704 | 190 0.999997 0.006928 | 315 0.999908 0.000633 66 1.000052 0.0085 | 191 0.999997 0.005113 | 316 0.999908 -0.00132 67 1.000052 0.00729 | 192 0.999997 0.005113 | 317 0.999908 -0.00132 68 1.000052 0.00729 | 193 0.999997 0.005113 | 318 0.999908 -0.00132 69 1.000052 0.00729 | 194 0.999997 0.005113 | 319 0.999949 -0.000018 70 1.000024 0.008214 | 195 0.999997 0.005113 | 320 0.999949 -0.00085 71 1.000024 0.006935 | 196 0.999997 0.005113 | 321 0.999941 0.0000681 72 1.000018 0.00845 | 197 0.999997 0.005113 | 322 0.999941 -0.00093 73 1.000018 0.0067 | 198 0.999997 0.005113 | 323 0.999941 -0.00093 74 1.000018 0.008257 | 199 0.999997 0.005113 | 324 0.999941 -0.00093 75 1.000018 0.006689 | 200 0.999997 0.005113 | 325 0.9999 0.000256 76 1.000018 0.006689 | 201 0.999997 0.005113 | 326 0.9999 -0.00148 77 1.000018 0.006689 | 202 0.999966 0.006938 | 327 0.9999 -0.00215 78 0.99998 0.008199 | 203 0.999966 0.005147 | 328 0.999961 -0.000008 79 0.99998 0.00683 | 204 0.999919 0.006827 | 329 0.999961 -0.00101 80 0.999969 0.008258 | 205 0.999919 0.00519 | 330 0.999961 -0.00101 81 0.999969 0.006682 | 206 0.999943 0.006884 | 331 0.999961 -0.00101 82 0.999978 0.008042 | 207 0.999943 0.005562 | 332 0.999962 -0.00014 83 0.999978 0.006981 | 208 0.999886 0.006935 | 333 0.999962 -0.00139 84 1.000003 0.008231 | 209 0.999886 0.004688 | 334 0.999984 -0.000019 85 1.000003 0.006532 | 210 0.999918 0.006777 | 335 0.999984 -0.00122 86 1.000003 0.006532 | 211 0.999918 0.004838 | 336 0.999965 0.0000919 87 1.000003 0.006532 | 212 0.999951 0.00643 | 337 0.999965 -0.00116 88 0.999971 0.008156 | 213 0.999951 0.005236 | 338 0.999974 0.000235 89 0.999971 0.006674 | 214 0.999951 0.005236 | 339 0.999974 -0.00102 90 0.999946 0.007911 | 215 0.999951 0.005236 | 340 0.999984 -0.00023 91 0.999946 0.006303 | 216 0.999998 0.006688 | 341 0.999984 -0.00138 92 0.999946 0.006303 | 217 0.999998 0.004688 | 342 0.999995 0.000637 93 0.999946 0.006303 | 218 0.999933 0.006314 | 343 0.999995 -0.00122 94 0.999946 0.006303 | 219 0.999933 0.004831 | 344 0.999995 0.001024 95 0.999966 0.008344 | 220 0.999957 0.002581 | 345 0.999995 -0.00019 96 0.999966 0.006289 | 221 0.999957 0.001114 | 346 0.999995 0.001018 97 0.999966 0.007755 | 222 0.999986 0.001947 | 347 0.999995 -0.00019 98 0.999966 0.006223 | 223 0.999986 0.000596 | 348 0.999995 0.000468 99 0.999999 0.008071 | 224 0.999936 0.001738 | 349 0.999995 -0.00038 100 0.999999 0.00636 | 225 0.999936 0.000237 | 350 0.999995 0.000811 101 0.999999 0.00636 | 226 0.99998 0.002004 | 351 0.999995 -0.0004 102 0.999999 0.00636 | 227 0.99998 0.000515 | 352 0.999995 0.000455 103 0.999956 0.008208 | 228 0.999991 0.001325 | 353 0.999995 -0.00038 104 0.999956 0.006075 | 229 0.999991 -0.00042 | 354 0.999942 -0.0000065 105 0.999956 0.00797 | 230 0.999956 0.00102 | 355 0.999942 -0.00047 106 0.999956 0.006163 | 231 0.999956 -0.00056 | 356 0.999976 0.000123 107 0.999956 0.006163 | 232 0.999968 0.000492 | 357 0.999976 -0.00037 108 0.999913 0.007599 | 233 0.999968 -0.0008 | 358 0.999958 0.000268 109 0.999913 0.00592 | 234 0.999982 0.000854 | 359 0.999958 -0.00022 110 0.999913 0.00592 | 235 0.999982 -0.00054 | 360 0.99996 0.00031 111 0.999913 0.00592 | 236 0.999942 0.00079 | 361 0.99996 -0.00012 112 0.99989 0.007439 | 237 0.999942 -0.00073 | 362 0.99996 -0.00019 113 0.99989 0.005707 | 238 0.999926 0.000677 | 363 0.99996 0.000261 114 0.999946 0.007031 | 239 0.999926 -0.00107 | 364 0.99996 -0.0004 115 0.999946 0.00535 | 240 0.999909 0.000873 | 365 0.99996 -0.00023 116 0.999946 0.00535 | 241 0.999909 -0.00074 | 366 0.99996 0.000527 117 0.999946 0.00535 | 242 0.999952 0.000132 | 367 0.99996 -0.000068 118 0.999894 0.007352 | 243 0.999952 -0.0008 | 368 0.99996 -0.000068 119 0.999894 0.005468 | 244 0.999912 0.000461 | 369 0.99996 -0.00024 120 0.99992 0.007035 | 245 0.999912 -0.00089 | 370 0.99996 0.00018 121 0.99992 0.005618 | 246 0.99993 0.000654 | 371 0.99996 0.00018 122 0.99992 0.005618 | 247 0.99993 -0.00093 | 372 0.99996 0.00018 123 0.99992 0.005618 | 248 0.99993 -0.00093 | 373 0.99996 0.000274 124 0.99995 0.006594 | 249 0.99993 -0.00093 | 374 0.99996 -0.00025 125 0.99995 0.005225 | 250 0.999948 0.0005 | 375 0.99996 -0.00025 C.3. CTD The CTD probes (Models 8737 and 8705) used during this cruise are made by Guildline Instruments of Smiths Falls, Ontario, Canada. Their resolution and accuracy will be provided when data is submitted. An additional Guildline CTD with a high precision pressure sensor was used when weather would not allow rosette casts. C.4. Salinity Samples were collected in glass bottles and analyzed onboard ship using a Guildline Model 8410 Portasal. The Portasal was standardized daily with IAPSO standard sea water Batch P125. Salinity and nutrient measurements were made in an air conditioned lab (see Table 4.). C.5. Oxygen Samples were drawn through either amber rubber or Tygon tubing into 125 ml iodine flasks. The flasks were allowed to overflow twice their volume before being stoppered then unstoppered, fixed with manganous and iodide reagents according to Carpenter (1965), restoppered and shaken thoroughly. Sample temperatures were measured before initial stoppering to +/- 0.5 C. To avoid outgassing during analyses, samples were initially all refrigerated at 4 C for 1 to 24 hours before being titrated with an auto-burette (Brinkman Dosimat) to an iodine colorimetric endpoint. By station W042, samples from the mixed layer were pulling in sizable air bubbles when they were cooled. At 2 stations (W050 and W058), the effect of air contamination of pickled samples was tested and shown to add 1 to 3 umol/kg oxygen to surface samples that are cooled. This bias remains in surface layer data from stations W042 to W050, and will vary in amount depending on the amount of cooling (volume change) for each sample. Surface layer samples from W051 to W070 were not cooled. On Leg 2, flasks were sealed with tap water around the lip of the flask. This greatly reduced the amount of oxygen that enters a flask during cooling. Samples were routinely refrigerated before being analyzed. Standards were prepared as outlined in WOCE Report 73/91. C.6. Nutrients Samples were collected in 50 ml polyethylene tubes and refrigerated for a maximum of 12h (rosette) or 30 h (USW) before being analyzed. A 4 channel Technicon Analyzer measured NO3 + NO2, NO2, PO4 and dissolved Si. Analytical procedures are essentially those described by Koroleff and Grasshoff (1983). Concentrated standards were prepared from oven dried (80oC) reagents shortly before sailing on Leg 1 and again in Honolulu. Working standards were made every 1 to 2 days by diluting 1 to 6 ml of various stock solutions to 250 ml with 3.2% NaCl (w/v in double run Milli-Q water). Nitrate, nitrite and silicate standards were compared to Sagami standards. The nitrate standards agreed to within 0.1 mmol/l, but the silicate concentrations differed by 2%, an unusual finding since our prepared standards usually agree very well with the stable Sagami standards. Our silicate standard was checked on a recent cruise and again compared to Sagami and it was found to be low by 2.2%. We compared our results with data from one matching station on the Cruise TT190 of the R/V Thomas Thompson in 1985 and found that below 1000 m our silicate results are comparatively low by an average of 2.2%. No corrections have been applied to our data, although in consultation with a WOCE DQE, this might be done. Nutrient lab temperatures were recorded approximately hourly during analyses and are recorded in TABLE 11: Nutrient Lab Temperatures Nutrient Lab Temperatures, Leg 1 Date Station Temperature (C)| Date Station Temperature (C) -----------------------------------|-------------------------------------- 7 Sep. JF1-P04 22.4/22.8 | 27 Sep W035/36/33 22.4/22.4/23.2 8 Sep. P13 23.1/23.8/23.9 | W034 24.6 9 Sep. P14 to P18 22.5/23.9 | 28 Sep W037/38/39 21.4/28.6/25 P18 22.8/24.4 | 29 Sep W040/41/43 22.4/23.3/23.1 10 Sep P19 to P35 23.3/23.4 | W042 23.0 P26 23.4/24.3 | 30 Sep W044/45/46 23.5/22.7/23.7 16 Sep W004 21.3/22.4/21 | 1 Oct W047/48/49 22.9/23.6/23.1 19 Sep W002/3/4 23.2/23/23.4 | 2 Oct W051/50 24.2/24.3 W005 23.6 | 3 Oct W052/53/54 23/23.8/24 20 Sep W006/W011 23.7/23.9 | W055 24 21 Sep W012/13/14 23.8/23.8/23 | 4 Oct W056/58/59 24.8/24.8/24.9 W015 24.4 | 5 Oct W060/61 25.2/24.8/24.9 22 Sep W016/17/18 23.5/23.5/23.7 | 6 Oct W062/63/64 25.2/-/24.9 24 Sep W025 24.4 | W065 25 25 Sep W026/27/28 22/22.5/24 | 7 Oct W067/66/68 24.7/25.7/- W029 24.3 | W070 25.1 26 Sep W030/31/32 25.3/25.6/25.2 | -------------------------------------------------------------------------- Nutrient lab temperatures, Leg 2: Date Station Temperature | Date Station Temperature -----------------------------------|-------------------------------------- 18 Oct W071/W072 25..0 | 29 Oct W108/W109 25.7/25.3 19 Oct W073/W074 25.8/25.5 | 30 Oct W111/W112 25.1/24.0 20 Oct W078/W079 23.8/24.9 | 31 Oct W113/W114W115 -/-/25.0 21 Oct W080/W081/ 24.5/24.3 | 1 Nov W116/W117 26/25.3 W082/W083 25.1/24.5 | W118 24.8 22 Oct W084/W085 24.4/24.9 | 2 Nov W119/W120 24.9/25.2 W086/W087 25.2/24.5 | 23 Oct W088/W089 24.8/24.9 | 3 Nov W123/W124 -/25.9 W090/W091 25.5/25.4 | W125 26.1 24 Oct W092/W093 25.9/26.3 | 4 Nov W126/W127 22.9/23.5 25 Oct W096/W097 23 | W128/W129 -/- W098 23/23.2 | 26 Oct W099/W100 25.2/25.6 | 5 Nov W130/W131 23.1/24.1 W101 25.6 | W132 24.1 27 Oct W102/W103 24.7/26 | 7 Nov W133/W134 -/- W104/W105 25.8/24.6 | W135 24.1 28 Oct W106/W107 25.6/26 | 8 Nov W136 24.6 -------------------------------------------------------------------------- Phosphate samples were occasionally contaminated during the second half of the first leg. A nitrate reagent containing phosphoric acid was spilt on September 30 when Stations W044, W045, and W046 were analyzed. On October 1 it was noted in the nutrient log that the crew were washing the deck with soap - Stations W047, W048 and W049 were analyzed on this day. Our water demineralizing system failed during Leg 2, which forced us to use low nutrient sea water to establish a baseline during analyses, and for the preparation of standards. Each day, a sample of 3.2% NaCl in double run Milli-Q water was analyzed to assess zero concentrations. Silicate and phosphate in low nutrient wash water was typically 2 and 0.2 uM higher than the clean salt solution. Crystals developed in the nitrite line from Station 123 onwards. This data has been labelled quality 3 for nitrite. An error is introduced into nitrate data since nitrite is subtracted from the NO3 & NO2 analysis results. Consequently, nitrates have also been assessed as questionable (quality 3) although the actual offset is only 0.1 to 0.3 umol/kg. Summing nitrite and nitrate will provide correct NO3 + NO2 values. C.6. CFCs CFC-11 and CFC-12 were analyzed by the method of Bullister and Weiss (1988). Our use of an aging Hewlett-Packard GC created problems. For the first days on Line PR6, corrosion on a circuit board shut the system down. Then as we sailed from Honolulu, the GC failed completely and we had to return to pick up another that was flown to us from IOS. Stations were occasionally skipped as columns were cleaned after they saturated with CFCs. Carrier blanks, stripper blanks, and restripped samples were analyzed throughout the cruise. Syringe air samples were taken from above the bridge, the aft deck where sampling was done, and inside the lab container. Working standard tank number 63098 was used for Stns 71, 72, 73 and 74 and tank number 63100 was used for the remaining stations. (Tank 63100 values: F-11, 583.10 ppt, standard deviation 2.05, and F-12, 279.18 ppt, standard deviation 1.04. Tank 63098 values: F-11, 443.63 ppt, standard deviation 2.63 and F-12, 502.81, standard deviation 1.91). These standards were made up of outside air. The tanks were calibrated against COCC's lab standard tank number 63088 (F-11, 457.59 ppt, standard deviation 0.55; and F-12, 263.13 ppt standard deviation 0.76). This COCC lab standard was calibrated by John Bullister's lab in October 1993. Data reduction was carried out using an adapted Scripps program (Weiss). This program requires salinity and temperature for calculations; the former was taken from Salinometer data; and the latter was read from the sample bucket when the syringe was removed and attached to the extraction system. There were some difficulties encountered throughout the cruise that hampered obtaining optimal results: 1) A problem with the consistency of the quality of the carrier gas meant having to subtract higher than normal stripper blanks. 2) The results of stations 83 to 97 may show zero at the 300 to 400 m depth because the threshold was initially set as per the 5890 GC program. This was modified for later stations in order to have very small peaks integrated. Thus these zero values may be a factor of threshold setting rather than a complete absence of Freon. 3) During some of the earlier stations we encountered samples affected by some sort of interference. This resulted in the F-11 peak being split or at other times summed, usually in the fifty meter sample. Neither using the split value or a summed value seemed to give a reasonable result so these samples were flagged as questionable or bad. This problem was also encountered on the first leg of the cruise. The restrips of water samples demonstrated the high stripper efficiency of the Freon analysis system. Air samples were usually taken around noon. The values reported were initially calculated with the Freon analysis program. If a particular station had a stripper blank run, the program automatically subtracted this before printing the final results. If a station did not have a stripper blank, a manual blank subtraction was applied to the calculated results based on deep water values. Limit of Detection Because contamination for F-12 was variable from day to day, detection limits were estimated each day as 3 times the standard deviation of deep sample concentrations. Thus from 2 to 7 samples were used to assess LODs in the range 0.025 to 0.244 umol/kg. Any value below this limit of detection was reported as zero. Both carrier gas and bottle blanks (deep ocean samples) were consistently zero for F-11. The lowest discernible value was 0.045 umol/kg. TABLE 12: Freon levels of air (ppt): Stn Above bridge Sampling deck Lab -------------------------------------------------------- F-11 F-12 F-11 F-12 F-11 F-12 -------------------------------------------------------- 74 252.44 612.17 280.13 852.97 300.20 615.32 74 281.21 504.43 287.27 595.06 86 271.60 507.90 315.61 366.25 86 277.83 602.34 98 279.67 673.46 271.10 571.56 273.99 493.60 101 272.04 531.47 281.40 1301.14 279.87 820.70 106 249.57 528.55 258.47 673.47 264.18 1194.8 108 263.07 518.75 261.66 516.57 265.45 689.58 113 360.34 580.22 271.18 765.35 321.11 524.49 -------------------------------------------------------- C.7. Total CO2 The coulometric procedure outlined in DOE (1994) was used to measure carbon dioxide in sea water. Samples were collected in 250 ml GS bottles, fixed with 200 ul of saturated HgCl2 solution, and cool stored until analyzed. C.8. Alkalinity Following the method of DOE (1994), alkalinity was determined using a temperature stable (25 C) closed titration cell, a Metrohm 665 Dosimat, a Metrohm 649 stir apparatus and an Orion model 720A pH meter. D. Acknowledgments E. References Bullister, J.L. and R.F. Weiss (1988). Determination of CCl3F and CCl2F in seawater and air. Deep-Sea Research, 35,839-853. Carpenter, J.H. 1965. The Chesapeake Bay Institute technique for the Winkler dissolved oxygen method. Limnology Oceanography 10: 141-143. DOE. 1994. Handbook of methods for analysis of the various parameters of the carbon dioxide system in sea water; version 2. A.G. Dickson and C. Goyet, eds. ORNL/CDIAC-74. Koroleff, F. and K. Grasshoff. 1983. Determination of nutrients. in Methods of Seawater Analysis. eds. K. Grasshoff, M. Ehrhardt, K. Kremling. Unesco, 1983. International Oceanographic tables. Unesco Technical Papers in Marine Science, No. 44. Unesco, 1991. Processing of Oceanographic Station Data. Unesco memorgraph By JPOTS editorial panel. Weiss, R.F. Freon Lab Manual, Unpublished manuscript, Scripps Institute of Oceanography, San Diego, California, USA WOCE Report No. 73/91, 1991. A comparison of Methods for the Determination of Dissolved Oxygen in Seawater. WHPO Publication 91-2. F. WHPO Summary Figures 3 and 4 are not presented in this report due to CTDOXY not being available. Several data files are associated with this report. They are the 18DD9403_1.sum and 18DD9403_2.sum, 18DD9403_1.hyd and 18DD9403_2.hyd, 18DD9403_1.csl and 18DD9403_2.csl and *.wct files. The P13j.sum file contains a summary of the location, time, type of parameters sampled, and other pertinent information regarding each hydrographic station. The *.hyd file contains the bottle data. The *.wct files are the ctd data for each station. The *.wct files are zipped into one file called *wct.zip. The P13j.csl file is a listing of ctd and calculated values at standard levels. The following is a description of how the standard levels and calculated values were derived for the *.csl file: Salinity, Temperature and Pressure: These three values were smoothed from the individual CTD files over the N uniformly increasing pressure levels. using the following binomial filter- t(j) - 0.25ti(j-1) + 0.5ti(j) + 0.25ti(j+1) j-2....N-1 When a pressure level is represented in the *.csl file that is not contained within the ctd values, the value was linearly interpolated to the desired level after applying the binomial filtering. Sigma-theta(SIG-TH:KG/M3), Sigma-2 (SIG-2: KG/M3), and Sigma-4(SIG-4: KG/M3): These values are calculated using the practical salinity scale (PSS-78) and the international equation of state for seawater (EOS-80) as described in the Unesco publication 44 at reference pressures of the surface for SIG-TH; 2000 dbars for Sigma-2; and 4000 dbars for Sigma-4. Gradient Potential Temperature (GRD-PT: C/DB 10-3) is calculated as the least squares slope between two levels, where the standard level is the center of the interval. The interval being the smallest of the two differences between the standard level and the two closest values. The slope is first determined using CTD temperature and then the adiabatic lapse rate is subtracted to obtain the gradient potential temperature. Equations and Fortran routines are described in Unesco publication 44. Gradient Salinity (GRD-S: 1/DB 10-3) is calculated as the least squares slope between two levels, where the standard level is the center of the standard level and the two closes values. Equations and Fortran routines are described in Unesco publication 44. Potential Vorticity (POT-V: 1/ms 10-11) is calculated as the vertical component ignoring contributions due to relative vorticity, i.e. pv-fN2/g, where f is the coriolis parameter, N is the buoyancy frequency (data expressed as radius/sec), and g is the local acceleration of gravity. Buoyancy Frequency (B-V: cph) is calculated using the adiabatic leveling method, Fofonoff (1985) and Millard, Owens and Fofonoff (1990). Equations and Fortran routines are described in Unesco publication 44. Potential Energy (PE: J/M2: 10-5) and Dynamic Height (DYN-HT: M) are calculated by integrating from 0 to the level of interest. Equations and Fortran routines are described in Unesco publication 44. Neutral Density (GAMMA-N: KG/M3) is calculated with the program GAMMA-N (Jackett and McDougall) version 1.3 Nov. 94. G. DATA QUALITY EVALUATIONS G.1. EVALUATION OF CTD DATA FOR WOCE LINE P15N, LEG 1 (Bob Millard) June 3, 1998 WOCE cruise P15N is a North to South section along 165 W from South of the Aleutian Islands (54 N) to the Hawaiian Islands (21 N). A wide range of surface salinity and temperature is encountered as the overall potential temperature versus Salinity plot of figure 1a shows. All of the 2 decibar CTD data are displayed on this plot as are all up cast CTD and water bottle salinity. Station numbers have been modified to remove the W (i.e. W070 - 70) but otherwise are identical to those found in the ___.WCT and ____.hyd files. A second overall potential temperature versus Salinity (Theta/S) plot given in figure 1b shows the deeper water salinity variability. In the deep water Theta/S plot, figure 2b, the salinity variability increases as the potential temperature increases and the higher salinity values are found at the Southern end of the section. There are no CTD oxygen data reported and therefore oxygen is not examined. The CTD salinity data are generally well matched to the bottle values through out this cruise leg. This report examines salinity, temperature and pressure data for both the 2 decibar CTD profiles (____.WCT) and the subset of the CTD data collected with the water samples in the _____.hyd file. Particular attention is given to the salinity comparisons. The documentation on laboratory and in situ calibrations of pressure and temperature are reviewed from the cruise report. Two CTD are used . A WOCE accuracy Guildline CTD #6 for deep casts and an Ocean Physics CTD for shallow casts. Electronic reversing thermometers and pressure sensors were available to monitor pressure and temperature calibrations in the field. The electronic thermometers were used to correct the Ocean Physics CTD pressure and temperature and pressure but not the Guildline CTD. I didn't examine the shallow (500 to 1000 decibars) CTD cast with Transmissometer. There were often 2 casts in bottle file to obtain more than 24 water samples. For this evaluation I treated both casts of bottle file as one cast associated with the deep CTD cast. Only the Guildline CTD data is evaluated in this report. The Paros pressure transducer is corrected to the laboratory calibrations. There is no mention of how the Paros sensor was calibrated in the laboratory (i.e. type of deadweight tester or some other pressure transfer standard?). I found the temperature calibration description confusing . The data report mentions that the Guildline CTD6 did not have a pre cruise temperature calibration. Wasn't one done at the factory before being returning?. The post cruise temperature calibration was relied on together with monitoring of the primary temperature against two addition slow responding thermistors and the electronic thermometers. Only one of the thermistors was found to be reliable and the electronic reversing thermometers evidently were not found to be accurate enough to make calibration adjustments. An adjust of 0.002 C was applied to the Guildline copper thermometer based on comparisons with neighboring stations below 4000 dbars . It is not clear if the temperature comparisons are made with neighboring stations from other WOCE cruises. There was no mention of other cruises, dates, etc.? Is the temperature correction applied as a bias at all temperatures (most likely) or only at pressures greater than 4000 dbars as implied in the cruise report.. SALINITY EVALUATION: The water bottle salinity samples were analyzed on a Guildline PortaSal using standard water batch P121. A discussion of the variability of recent batches of standard water has been carried out by Micho Ayamo and others. which shows the salinity adjustment of standard water batches including P121. P121 has a measured salinity that is lower than the label salinity by 0.001 to 0.0015 psu. Comparisons of water sample and CTD salinity are cared out to assess how well the CTD salinity matches the bottle salts for all stations and at all pressure levels. The salinity difference Ds - (CTD - WS) [Water Sample] for the up profile data taken from the water sample ____.hyd file is displayed in figures 2a, b, &c. The down profile salinity differences (interpolated at pressure levels) are displayed in figures 2d, e & f. The salinity differences at all pressure levels are displayed in the first panels (a & d) followed by only the differences at pressures greater than 2000 dbars (2 b & e) and finally all stations are displayed versus pressure in panels (2c & f). No individual stations salinity stands out as poorly calibrated to the bottle salinity. There is a slight indication that the CTD salinity is a little higher than the bottles below 4500 dbars in figures (2c & f). Also a few deep up cast comparisons exceed -0.005 psu in figure 2c. A waterfall plot of up cast salinity differences are displayed in figure 3a and indicate that the deep salinity difference of station 27 are offset fresh. An expanded scale display of this plot (figure 3b) shows that station 27 in deed has larger differences than those of neighboring stations while the down profile Ds waterfall plot (figure 3c) of the same station group shows no such offset. A plot of the Theta/S shows the Up cast CTD of station 27 to be to fresh and should be flagged as such in the bottle file (___.hyd). Histograms of salinity differences over the following 6 pressure intervals of 0 to 500, 500 to 1000 , 1000 to 1500, 1500 to 3000, 3000 to 4500 and 4500 to 6500 dbars for both the up CTD salinity in figure 4a and down CTD salinity in figure 4b. The standard deviation of salinity differences below 3000 dbars are extremely well behaved ranges from less than 0.001 psu in the pressure interval 4500 to 6500 dbars to 0.0015 psu in the pressure range from 3000 to 4500 dbars. The average salinity difference from 3000 to 6500 dbars is nearly zero. (.0002 psu or less). This seems to contradict figure 2 c & f which suggests that the CTD salinity appears to be high compared to the bottle data below 4500 dbars. An average salinity profile at potential temperature intervals was formed for stations 4 through 70 and is plotted with +/- one standard deviation of salinity for the deep water in figure 5. The red circles are water sample salinity values which appear to be nicely distributed on either side of average CTD salinity. A plot of salinity anomalies from the average theta/s clearly shows the salinity at a potential temperature level increases from North to South above 1.15 C. The magnitude of the North/south salinity variation on a pot. temp. surface increases with increasing potential temperature but below 1.15 C this pattern is not evident although this may be due to the lack of a salinity signal large enough to be distinguished from the uncertainty of the salinity measurements. Deep potential temperature versus salinity (THETA/S) plots for a couple of problem CTD stations are shown in figures 6 a - b. An examination of deep Theta/S plots like figures 6 a & b for all stations (see figure 1b) shows many of the 2 dbar CTD stations appear to be salty compared to water bottle salts below potential temperatures of 1.15 C. The salinity of station 6 is fresh by 0.003 psu compared to neighboring stations shown on figure 6 a & b or any other profile taken on this leg although the CTD salinity does match the water sample salts. The CTD salinity profiles for station W024 appears to be 0.005 psu salty for theta's below 1.4 C compared to station to the North or South. Station W023 is also slightly salty (~0.002 psu) deep. The salinity difference of both of these stations with neighbors decreases with decreasing potential temperature. Both stations 23 and 24 have an increased salinity noise level discussed later. The up cast CTD profile for station 27 (black circles on figure 6b) clearly shows the up CTD salinity values deep to be fresh compared to the water samples and neighboring profiles around 1.1 C (as mentioned earlier in conjunction with the waterfall delta-s plots of figure 3b). COMPARISON WITH HISTORICAL DATA: TPS47 AND TPS24 Two earlier East-West hydrography Sections were carried out along 24 and 47 North in 1985. Referred to as the transpacific sections (TPS), one was along 47 N (TPS47) and the other along 24 N (TPS24 ). The water sample salinity samples for both of these cruises were standardized to P96. Stations at or near the crossing of 165 W are shown for 47 N and 25 30 N together with the comparable stations from P15N in figures 7 a & b. Both of these potential temperature versus salinity plots indicate that the deep salinity observations of P15N are salty compared with these earlier cruises. The water sample data for cruises TPS24 and TPS47 is shown as red (X's) while TPS47 CTD data of TPS24 and TPS47 are red, magenta and also green (TPS24). The TPS24 CTD data is also distinguishable by the coarser 0.001psu salinity quantizing (figure 7b). The TPS47 CTD and water sample salinity are fresh by 0.0025 psu compared to P15N salinity over the entire range of potential temperature shown in figure 7a. The TPS24 CTD and water sample salinity are fresh by 0.001 psu in figure 7b compared to P15N salinity but this salinity difference decreases at lower potential temperatures. When the theta/S plots of TPS47 and TPS24 are overlaid their salinity curves are observed to merge at coldest common value of 1.10 C which reinforces the earlier observation from the P15N mean Theta/S profile that observable North-South salinity variations around this potential temperature are to small to be resolved in the transpacific sections as well. Since the comparison of TPS 24 and TPS47 involves two standard water (SSW) batches P96 and P121, the works of Mantyla (1980 and 1987) and Aoyama, et al. (1998? DSR) should be consulted before drawing any conclusions on adjustments to salinity data. Aoyama ,et al. (1998?) gives a plot of SSW variations Ds- (Smeasured-Slabel) that includes both P96. SALINITY NOISE: The CTD salinity is high-pass filtered to exclude salinity variations with vertical scales longer than 25 dbars . Figure 8a shows the RMS of the salinity scatter on a station by station basis for two depth intervals: the red curve is from 3000 dbars to the bottom given in figure 8c and the green curve is from 1000 dbars to the bottom. Assuming that oceanic salinity variations with scales less than 25 dbars are absent below 3000 dbars the red curve gives an indication of the instrumental salinity noise. The salinity fluctuations below 3000 dbars in the 4 to 25 dbars wavelengths has an station averaged RMS of.00017 psu and a minimum RMS of 0.00012 psu. The minimum RMS noise level in salinity is probably an indication of instrumental noise which at 0.00012 psu is at the low end of values observed other data sets examined which varies from 0.0001 to 0.00035 psu. The RMS salinity plot versus station allows unusually noisy stations for salinity to be better identified without a point by point examination. Two Stations 23 & 24 have noisy salinity's signals relative to other stations which was identified earlier in figure 6b. These two stations have an RMS salinity 2.5 times the average salinity noise level for pressures greater than 3000 dbars. Station 57 also has noise in salinity but doesn't extend to 3000 dbars. All three these CTD stations (23, 24 and 57) are missing corresponding water sample data in the bottle file which perhaps indicates that the CTD and rosette misbehaved together? The final graph shows the pressure level of those stations which exhibited density inversions in excess of -0.005 and -0.01 kg/m^3/dbar. A total of 16 observations listed in table I and plotted in figure have density instabilities exceeding -0.005 g/m^3/dbar while only 12 exceed the -0.01 kg/m^3/dbar criteria. The 16 density instability observations of the 10 stations listed in Table 1 are the values plotted on figure should be reviewed. TABLE 1 dsg/dp Station # Pressure Salinity --------------- -------------- -------------- -------------- -1.0054632e-002 4.0000000e+000 5.6000000e+001 3.2588900e+001 -7.6895939e-003 6.0000000e+000 5.0000000e+001 3.2581400e+001 -9.2450718e-003 1.6000000e+001 5.2000000e+001 3.2924600e+001 -1.2499790e-002 3.1000000e+001 7.4000000e+001 3.3872300e+001 -7.8494724e-003 3.3000000e+001 1.1400000e+002 3.4127600e+001 -5.1070095e-003 3.4000000e+001 1.2400000e+002 3.4227400e+001 -6.7298463e-003 3.8000000e+001 4.0000000e+000 3.4503300e+001 -1.3519456e-002 3.8000000e+001 8.0000000e+000 3.4459200e+001 -1.3213828e-002 3.8000000e+001 1.0000000e+001 3.4423900e+001 -6.1580665e-003 3.8000000e+001 1.2000000e+001 3.4407800e+001 -1.0596627e-002 3.8000000e+001 1.4000000e+001 3.4379500e+001 -1.8276013e-002 4.8000000e+001 8.6000000e+001 3.4583300e+001 -5.8305896e-003 4.8000000e+001 8.8000000e+001 3.4567400e+001 -1.6425674e-002 5.0000000e+001 7.0000000e+001 3.4688900e+001 -1.0469056e-002 5.0000000e+001 7.8000000e+001 3.4650900e+001 -1.3821924e-002 6.3000000e+001 2.2200000e+002 3.4723100e+001 REFERENCES: Aoyama, Michio, T. M. Joyce, T. Kawano, and Y. Takatsuki (1998?) Offsets of the IAPSO Standard Seawater for P103 through P129. Submitted Deep_sea Research . Mantyla, A.W. (1980) Electrical conductivity comparisons of standard seawater batches P29 to P84. Deep_sea Research 27A, 837-846. Mantyla, A.W. (1987) Standard Seawater comparison Updates Physical Oceanography, 17, 543-548. Figure 1 All Bottle & CTD a: Overall Theta/S ; b: deep Theta/S Figure 2 Salinity differences a-c] (CTD up cast - WS) d-e] (CTD down cast - WS) Figure 3 Waterfall up cast salt differences (CTDup-WS) psu Figure 4 Waterfall plots sta. 25 to 40 a: up cast b: down cast Figure 5 Histograms salinity differences for indicated intervals: a: (CTD up-WS) b: (CTD down - WS) Figure 6 CTD mean theta averaged salinity with over plot of bottle salinity (red o) Figure 7a Deep CTD Theta/S shows Station 6 is fresh along with WS salinity Figure 8b Deep Theta/S shows stations 23 & 24 salty and noisy Figure 9 Historical East/West Hydrographic sections a: 47 North; TPS47 b: 25 N TPS24 Figure 10a red - Salinity noise estimate (P>3000 dbars); green - 1000 to 3000 dbar variance up to 25 dbar cut-off: lower panel: Station bottom pressure; ignore middle Oxygen panel Figure 11 Density inversions: x - -.005 kg/m3/dbar & * - -.0075 kg/m3/dbars G. DATA QUALITY EVALUATION REPORTS G.2 EVALUATION OF CTD DATA FOR WOCE LINE P15N LEG 2 (Bob Millard) November 4, 1998 WOCE cruise P15N, second leg , is a North to South section along 165 W beginning in Hawaii (21 N) and ending at America Samoa (15 S). The range salinity and temperature encountered is indicated in the overall potential temperature versus Salinity plot shown in figure 1a. All of the 2 decibar CTD data are displayed on this plot as are all up cast CTD (o) and water bottle salinity (+). Some bottle salinities fall outside of the envelope of the CTD down salinity profiles A second overall potential temperature versus Salinity (Theta/S) plot shown in figure 1b gives the deep water salinity variability. Figure 2b, indicates that the geographic variability of salinity increases with increasing potential temperature. The higher salinity values in the deep water are observed to be at the Southern end of the section. There are no CTD oxygen data reported and therefore no discussion of oxygen quality is included. The CTD salinity data are generally very well matched to the bottle values throughout P15N leg 2 . This report examines salinity, temperature and pressure data for both the 2 decibar CTD profiles (____.WCT) and the subset of the CTD data collected with the water samples in the _____.hyd file. Throughout this report, the CTD station numbers have been modified by removing the W (i.e. W071 - 71 to facilitate handling by Matlab) but otherwise are identical to those found in the ___.WCT and ____.hyd files. The documentation on laboratory and in situ calibrations of pressure and temperature described in the cruise report are reviewed . Two CTD instruments were used to collect stations on the cruise. A WOCE accuracy Guildline CTD number 9901 was used for deep casts and an Ocean Physics CTD for shallow casts. I have not looked at the shallow CTD casts that used the Ocean Physics CTD with Transmissometer. Sometimes there were o two bottle casts to obtain more than 24 water samples. For this evaluation the data from both bottle casts were combined and associated with the deep CTD cast. The following comments refer to the calibration description in the cruise report for Guildline CTD number 9901. The Paros pressure transducer was corrected to the laboratory calibrations but no mention is made of how the Paros sensor was calibrated in the laboratory (i.e. type of deadweight tester or other pressure reference ?). I found the use of event number and station number to be confusing and prefer station number . The post cruise temperature calibration was relied on together with monitoring of the primary temperature against two addition slow responding thermistors. Figure 2 is taken from data of Table 10 from the cruise report shows temperature offset and conductivity slope adjustment versus event number ( event # 301 - CTD station 117) for the Guildline CTD stations of leg 2. The temperature offset applied to the Guildline copper thermometer shows a shift in temperature adjust at event 220. I wonder how much of the temperature offset adjustment should be attributed to an uncertainty of temperature ? The conductivity slope variation does not show much pattern with event # (station) but then the total range of adjustments is has an effect on salinity is less than 0.004 psu. SALINITY EVALUATION: The water bottle salinity samples were analyzed on a Guildline PortaSal using standard water batch P121. A discussion of the variability of recent batches of standard water can be found in Micho Ayamo, et al. (1998?) and Mantyla (1980, 1987). The salinity adjustment of standard water batches including P121 is given in tabular and graphical form. The measured salinity of P121 is lower than the labeled salinity by between 0.001 to 0.0015 psu according to Ayamo, et al. To assess how well the CTD salinity matches the bottle salts, the difference of CTD and water sample (WS) salinity are displayed versus both station and pressure. The up profile salinity difference Ds - (CTD - WS) are from the water sample data file (DD9403l2.hyd) and plotted in figures 3a, b, &c. The down profile salinity differences (interpolated from the 2 decibar data files ___.wct at the bottle pressure levels) are displayed in figures 3d, e & f. The salinity differences at all pressure levels are displayed in the first panels (a & d). The differences at pressures greater than 2000 dbars (2 b & e) also have the station mean salinity (red) with +/- one standard deviation (dashed magenta). Finally all stations are displayed versus pressure in panels (3c & f). No stations standout as having salinities off from the water samples. In general the CTD conductivity (salinity) match to the bottle salinity is very close. There is an indication that the CTD salinity is a bit higher than the bottles between 1000 and 3000 dbars in figures (3c & f). The deep CTD salinity match to the bottles has a low scatter (standard deviation-0.00134 psu) indicating careful handling of water sample salinities. Histograms of salinity differences over the following 6 pressure intervals of 0 to 500, 500 to 1000 , 1000 to 1500, 1500 to 3000, 3000 to 4500 and 4500 to 6500 dbars for both the up CTD salinity in figure 4a and down CTD salinity in figure 4b. The standard deviation of salinity differences below 3000 dbars are extremely well behaved ranges from less than 0.001 psu in the pressure interval 4500 to 6500 dbars to 0.0015 psu in the pressure range from 3000 to 4500 dbars. The average up and down salinity differences in the pressure intervals 1000:1500 and 1500:3000 is 0.0015 and 0.0011 psu respectively indicating CTD salinity to be slightly to high compared to the water sample salinities in these pressure ranges both for the down and up casts. An average salinity profile with potential temperature for stations 71 through 142 is shown figure 5a (overall) with +/- one standard deviation of salinity scater indicated. A similar plot for the deep water is presented in figure 5b . The black circles are water sample salinities and they seem to be very nicely distributed about the average CTD salinity and for the most part bounded by the one standard deviation envelope. The red (+ and *) indicate deep bottle salinities flagged in the bottle file as questionable (+) or bad (*) . It is not clear why these bottle salinities are marked as they seem to have a good agree with both the CTD and neighboring station water sample salinities. The (x) symbol indicates salinity differences Ds - ABS (CTD-WS) Ds > .01 for P>1000 dbars and Ds>.02 for P>500 & <1000 and Ds>.2 P<500. I have flagged these observations as questionable in the accompanying water sample file. I used the QUALT2 of attached bottle file (P15L2DQE.hyd) to indicate changes. A second file is abbreviated to include only those bottle levels where QUALT1 and QUALT2 differ (P15NL2DQE.CHG ). The variations of deep water (potential temperature range .8 and 2.0 C) salinity from the P15N LEG 2 average theta/s shows the salinity becoming progressively saltier in the most northern stations (stations 71 to 85) and then at around 12 N the salinity variation becomes weak for the remainder of the section. As was observed in P15N leg 1, below a potential temperature of 1.15 C no pattern of salinity variations is evident (perhaps a good region to compare P15N leg 2 with historical data) although this may be due to the lack of a salinity signal large enough to be distinguished from the uncertainty of the salinity measurements. COMPARISON WITH HISTORICAL DATA: MOANA WAVE CRUISE 893 An earlier East-West hydrography section was carried out along 9.5 degrees North on the R/V Moana Wave cruise 893 (MW893) in March of 1989 along WOCE line P4. The water sample salinity samples of this cruise were standardized to standard sea water (SSW) batch P97. Three stations around the crossing of 165 W (MW893 stations 113, 114, & 115) are plotted together with comparable stations near 9.5 N from P15N LEG 2 in figures 6. The agreement between the P15N LEG 2 stations (93 & 94) and the earlier Moana Wave cruise 893 stations (113, 114, & 115) is remarkable good and not just below a potential temperature of 1.115 C. The salinity agreement may be fortuitous , since the comparison of MW893 and P15N LEG 2 involves two standard water (SSW) batches P97 and P121. The work of Mantyla (1980 and 1987) and Aoyama, et al. (1998? DSR) should be consulted before coming to any conclusions. Aoyama ,et al. (1998?) has a plot of SSW variations Ds - (S_measured - S_label) that includes both P97 and P121. SALINITY NOISE: The CTD salinity is high-pass filtered to exclude salinity variations with vertical scales longer than 25 dbars . Figure 7a shows the RMS of the salinity scatter on a station by station basis for two depth intervals: the red curve is from 3000 dbars to the bottom given in figure 7b and the green curve is from 1000 to 3000 dbars. Assuming that oceanic salinity variations with scales less than 25 dbars are absent below 3000 dbars the red curve gives an indication of the instrumental salinity noise. The salinity fluctuations below 3000 dbars in the 4 to 25 dbars wavelengths has an station averaged RMS of.000217 psu and a minimum RMS of 0.00017 psu. The minimum RMS noise level in salinity is probably an indication of instrumental noise which at 0.00017 psu falls in the lower middle of values I have observed from other data sets examined which varies from 0.0001 to 0.00035 psu. The RMS salinity plot versus station allows unusually noisy stations for salinity to be better identified without a point by point examination. Two stations 116 & 138 stand out as having a possibly noisy salinity signal relative to other stations. These two stations have an RMS salinity 2.5 times the average salinity noise level for pressures greater than 3000 dbars. A Plot of station 116 versus pressure is shown in figures 8 while station 138 is shown versus pot. temp. in figure 9 (138 is the green profile , station 142, the blue profile is also noisy). A salinity shift can be seen to cause the excessive noise in station 116 while station 138 shows a generally noisier salinity profile deep. CTD SALINITY CALIBRATION The potential temperature versus salinity plot (figure 10a) indicates that station 125 (event 325) is 0.002 psu fresh compared to neighboring stations but appears to match its water sample. Referring back to figure 2a, the CCR value for event 325 is below the mean by -.00005 ( equivalent to ~ -0.002 psu). The potential temperature versus salinity plot of figure 10b shows station 130 (red) to be slightly noisy and salty (~0.002 psu) at the bottom, potential temp. < .9 C while figure 9 indicates station 142 (blue) to be ~`0.003 salty below a pot. temp. of 1.2 C. The final plot indicates the pressure levels of those stations which display density inversions in excess two thresholds. The 22 observations listed in table I and also plotted in figure 11 and represent those density instabilities exceeding -0.005 g/m^3/dbar (x) or the 7 observations (*) exceeding -0.0075 kg/m^3/dbar. These data should be reviewed. TABLE I dsg/dp Station # Pressure Salinity --------------- -------------- -------------- -------------- -5.0652578e-003 7.1000000e+001 1.9000000e+002 3.4885900e+001 -6.9063507e-003 7.1000000e+001 2.3600000e+002 3.4611900e+001 -5.2530943e-003 8.6000000e+001 1.7200000e+002 3.4584100e+001 -1.1897481e-002 8.7000000e+001 2.3200000e+002 3.4316700e+001 -5.6016986e-003 8.8000000e+001 9.8000000e+001 3.4788100e+001 -8.6937644e-003 8.8000000e+001 1.4400000e+002 3.4567600e+001 -5.3238841e-003 8.9000000e+001 1.4600000e+002 3.4520900e+001 -1.9042638e-002 9.2000000e+001 9.2000000e+001 3.4668500e+001 -5.3296535e-003 1.0900000e+002 1.0000000e+001 3.5140700e+001 -1.4713326e-002 1.1100000e+002 1.6800000e+002 3.5025700e+001 -2.0049596e-002 1.1100000e+002 1.8000000e+002 3.5003700e+001 -7.3997328e-003 1.1400000e+002 1.9400000e+002 3.5152800e+001 -5.4391194e-003 1.1500000e+002 1.9000000e+002 3.5106100e+001 -5.1336623e-003 1.2300000e+002 2.0200000e+002 3.5637900e+001 -5.1641391e-003 1.2800000e+002 6.0000000e+000 3.5289200e+001 -5.8081470e-003 1.2800000e+002 3.1200000e+002 3.4874900e+001 -5.0208606e-003 1.3000000e+002 2.2400000e+002 3.5467900e+001 -5.0407261e-002 1.3200000e+002 4.7600000e+002 3.4593700e+001 -3.7438432e-002 1.3500000e+002 2.4400000e+002 3.5736900e+001 -1.8335791e-002 1.3800000e+002 2.0000000e+000 3.5119400e+001 -9.9007993e-003 1.4000000e+002 3.4800000e+002 3.4907400e+001 REFERENCES: Aoyama, Michio, T. M. Joyce, T. Kawano, and Y. Takatsuki (1998? ) Offsets of the IAPSO Standard sea water for P103 through P129. Submitted Deep Sea Research. Mantyla, A. W. (1980) Electrical conductivity comparisons of standard sea water batches P29 to P84. Deep Sea Research 27A, 837-846. Mantyla, A. W. (1987) Standard sea water comparison Updates Physical Oceanography, 17, 543-548. Figure 1 All 2 dbar & bottle salinities (a) overall (b) deep Figure 2 (a) Cond. slope corrections (b) temp. adjustments Figure 3 Salinity differences at bottles (a, b, &c) [CTD up cast - WS]; (d, e, & f ) [CTD down cast - WS] Figure 3 Histograms (a) [CTD up cast -WS] (b) [CTD down cast - Ws] Figure 4 Pot. temp. average profile with WS (o) & quality (+) & (x): (a) Overall; (b) deep Figure 5 Comparison with R/V MW893 leg 3 Figure 6 Salinity noise variance (4 to 25 dbars): red p - 3002 dbars; green p - 1000 dbars Figure 7 Salinity noise source station 116 : prs. 3050 to 3100 dbars Figure 8 noise salinity station 138 (green); station 142 (blue) is salty deep Figure 9 (a) Station 125 (green) fresh (b) Station 130 (red) salty near bottom Figure 10 Density inversions versus pressure: (x) - -0.005 kg/m3/dbar & (*) - -0.0075 kg/m3/dbars G.3. DQ EVALUATION OF P15N SALINITY, OXYGEN AND NUTRIENTS (Arnold W. Mantyla) 28 March 2000 WOCE Section P15N ran from the Aleutian Islands south to Samoa along 165W to 170W close to the pre-salinometer era Alaska to Antarctica section that appears in Reid's classic "Intermediate Waters of the Pacific" monograph. With the closer WOCE station spacing, and more sensitive analytical techniques available to measure even more water constituents precisely, a clearer picture of the major Pacific gyre characteristics and water masses are now available. Although the analytical precision on the WOCE cruise was quite good, and comparisons with other cruises (WOCE, P04C, P02, TPS24, TPS47, INDOPAC and GEOSECS) agree reasonably well, there were a number of areas that did not meet WOCE guide- lines. The biggest deficiency was inadequate sampling in the vertical; the WOCE standard of 36 discrete levels was not matched on any station on this cruise. Two rosette systems were available, a 23 place and an 11 place system. Both of the rosettes were only used on about 1/4 of the stations sampling about 26 to 31 separate depths (less than the maximum available due to excessive duplicate depth trips). The 23 place rosette alone was used on the majority of the stations, with only 20 to 23 depths sampled in water as deep as 6000m. Occasional missing or contaminated measurements resulted in rather gappy profiles, 36 different sampling depths are really needed to properly cover the full water column for the chemical constituents. Because of the limited number of rosette bottles available, it would have been better to not waste any of them for multiple trips at the same depth. The multiple trips were often in high gradient regions, and the spread in the analytical results between duplicate bottle trips reflect more the difficulty in sampling the same water when in high gradients, than they do the intended measure of sample collection, storage, and analysis precision. For example, the standard deviation of the salinity differences between duplicate trips was .003, but nearly all of the deep water CTD and bottle salinity comparisons were closer to .001, which indicates that both the CTD and salinometer results were really quite good. The duplicate trips were not a good way to evaluate the analytical precision achieved on the cruise (unless the comparisons are limited to the mixed layer, or to other fairly uniform layers in the ocean). Likewise, targeting the same depth on both the shallow and deep casts serves no useful purpose other than to reveal the ocean is variable. The ideal way to sample 36 different depths with a 24 place and 12 place rosette is to select the 36 depths to sample from the down full water depth CTD salinity and oxygen profiles, with an awareness of the depths of anticipated nutrient extrema based upon earlier station profiles, or from nearby historical data. Counting up from the bottom, trip the 24 bottles at depths 1 to 23, and at depth 25. Then with the shallow 12 place rosette, sample depth 24 and then 26 to 36. Duplicate trips, if really needed, can be done at shallower stations with no loss of information. Another way to evaluate data quality without loss of trip levels would be to compare data on several constant potential temperature surfaces over the whole cruise. Station to station offsets and analytical scatter can easily be spotted and evaluated. The stations from 133 to the end of the cruise were limited to the top 3500m in water as deep as 5100m, because of winch problems. Those stations were recovered on P15S with full water column 36 place rosette casts; so the latter stations are to be preferred for the 170W section. The .sum file was not filled out very carefully. There were many duplicate cast times, as well as times that were clearly 12 or 24 hours off (times from one part of a cast appearing in the middle of a later station). The most obvious errors have been corrected, but someone with access to the original records should do a thorough re-check of the information. The .sea file did not show any CTD O2 data; that data would have been helpful in evaluating the water sample data. With no continuous CTD oxygen profile available, the few water sample oxygens are critical for defining the water column structure. Therefore, I was a little more apt to accept oxygen data that was only about 1% off, than were the data originators; slightly off data is better than no data at all. Water sample salinities were only listed to 3 decimal places after station 70, they should be listed to 4 places as was done on leg I, and also as was done with the CTD salinities on both legs. Salinities: There is a discrepancy in which Standard Sea Water batch used on the cruise; P125 according to the cruise report, and P121 according to the CTD DQE report. Should verify which one was actually used. The P15N salinities tended to be about .001 higher than the comparison cruises, which is within the expected variation of SSW standards. Oxygen: The whole bottle Carpenter oxygen technique was used on the cruise and the data agreement with crossing cruises was quite good, generally within about 1um. There were some small systematic errors for refrigerated warm water samples noted in the cruise report, introducing an error of plus 1-3um, or about 1% in those samples. That is in the same ballpark as the duplicate trip agreement, so I would prefer to accept those as ok rather than being flagged bad. I have changed some of the flags, but more could be accepted as ok and used in the vertical sections. A minor modification in sampling procedure could improve the oxygen analytical precision. The cruise report indicates the samples were collected after 200% overflow, stoppered, unstoppered, pickles, and re-stoppered. The re-stoppering step is difficult to do without introducing small air bubbles. If the pickling reagents can be kept near the rosette frame, then the sample can be pickled immediately and then stoppered without contamination while the flared part of the flask still contains sample water. The improved precision can easily be demonstrated by collecting and analyzing 10 samples out of a single large Niskin bottle both ways. The one-time stoppering method will usually result in a lower standard deviation for the 10 replicates. Also, if very low ambient oxygen water is sampled, they should be collected in clean, dry flasks, without rinsing, and with 300% overflow, (per Horibe, et al, J. Ocean. Soc. Japan, 28:203-206, 1972). In spite of the above comments, the oxygen data for this cruise generally look quite good, with no large offsets from other WOCE cruises. Silicate: The cruise report indicates that their primary silicate standard was 2% low compared to Sagami standards, unlike their usually good agreement with the Sagami standards. Also, the cruise results tend to be low compared to the WOCE crossing cruises by that amount. The PIs feel that the silicate data should be increased by 2%, but they have not done so. I agree, and recommend the data be multiplied by 1.02. Phosphate: Phosphates were the most frequently contaminated nutrient, with numerous scattered values clearly bad. The sparse vertical sampling intervals made the loss of any PO4 data regrettable, use of 36 place rosette might have minimized the information loss due to isolated bad PO4's. The deep PO4's tended to be about .05um high compared to other WOCE cruises, while numerous unlikely near zero surface values near the end of the first leg point toward a possible baseline or reagent blank problem. I have not flagged any of the zero um values, but I consider them to be questionable. The uncertainty only occurred on the first leg, there were no zero values on the second leg. Also, surface PO4's were often higher than the next deeper sample. This is a common problem when running low level nutrients immediately after a high level standard: To avoid the problem, run two surface samples and discard the first one. Nitrite: An analytical problem late in the cruise resulted in artificial deep NO2 values of 0.1 to 0.3, so much of the NO2 data after station 123 was flagged bad. The loss of the NO2 data is not serious, little occurs in deep water, but the problem created some uncertainty in the nitrate data. Nitrate: The NO2 error of 0.1 to 0.3 is large for nitrite, but small for NO3. The nitrate analyses involves the reduction of NO3 to NO2 and what is finally detected is the sum of the NO3 and NO2 originally in the sample. The NO2 present is usually subtracted from the NO3+NO2 to get the nitrate alone. Since many of the NO2's were doubtful on this cruise, many of the "corrected" NO3's were also considered to be doubtful. Since the NO2 error was in the NO2 analyzer alone, the erroneous NO2 values should not have been subtracted from the NO3 results (although they are "NO3+NO2", the deep NO2's are essentially zero). Therefore I recommend the NO3's be restored to their original values and the flags be re-set to ok. The corrected values will result in somewhat better agreement with historical data and with P15S, and will avoid a data gap in the vertical section. STA. 18: The deep NO2's below 200m are doubtful and have been flagged. If the second decimal place of the NO3's are available, the NO2 "corrections" should be added back in and the NO3's accepted as ok. STA. 27: The bottom 4 CTD salinities appear to have been truncated to .01, and are about .006 low. They have been flagged uncertain, but the original data should be checked to see if an error had occurred in the data tabulation. The PO4's appear to be about .1 low on all. Suggest re-check the factor or baseline offset. If calculated ok, recommend "u"ing all. STA. 31, cast 3 bottle 1: The data are listed at 5db, without any temperature, but are clearly from the bottom (even the listed CTD salinity). The data have been flagged uncertain, but would be ok if listed at the bottom with bottle number 2. STAS. 44-46: The majority of the oxygens have been flagged uncertain or bad, but the profiles agree well with adjacent stations and appear better than sta. 42. I would prefer to keep these as ok, unless there is a compelling reason to believe that they are indeed very poor. STAS. 45,47, 49, 51, 53, and 55: Bottles S9 and S10 are listed at different depths, but the salinity and nutrients are essentially identical, suggesting a double trip at the S10 bottle depth. Oxygen is at a local high gradient maximum, so the 2 trips are not necessarily the same in oxygen. I recommend flagging bottle S9 water samples as doubtful for these stations. STA. 50: The salinity at 4000db is exactly 0.3 off. Could this be a key entry error? STA. 52: Bottles 22 and 232 at 5db have no data, not even CTD temperature. Suggest delete, as no useful information. STA. 53: Bottles S7 and S9 at 115db and 145db appear to be listed one depth too deep, they would be ok one depth up. all of the water samples have been flagged uncertain. STA. 61, 5db: No CTD or water data, suggest delete. STAS. 63 and 65: Nitrates seem low, suggest re-check calculation factor compared to nearby stations. STAS. 66 and 69, 5db: No data suggest delete. STA. 74, bottle S1: No data, not even pressure. Suggest delete. STA. 94, 1248db: The nitrate was flagged bad, but would be ok if the poor NO2 correction was added back. STA. 108, cast 9, bottle S10: No data, not even CTD pressure. Suggest delete level (2503db). STA. 111: There was a shift (lower) in the phosphate on this and the following station, but not in nitrate, suggesting a change in standards. This should be looked into, and corrected, if possible. STAS. 123-136: All of the NO2's and NO3's have been "u"ed, however the NO3's would be ok if uncorrected for the NO2. Suggest adding the NO2 back to the NO3's and accepting the nitrates as ok. G.4 FINAL CFC DATA QUALITY EVALUATION (DQE) COMMENTS ON P15N. (David Wisegarver) Dec 2000 This data set, in its current form, does not meet the relaxed WOCE standard for CFC's. The original CFC flags (QUALT1) assigned by the PI have not been altered. During the DQE process, CFC QUALT1 flags of '2' (good) assigned by the PI have been given QUALT2 flags of '3' (questionable). Detailed comments on the DQE process have been sent to the PI and to the WHPO. The CFC concentrations have been adjusted to the SIO98 calibration Scale (Prinn et al. 2000) so that all of the Pacific WOCE CFC data will be on a common calibration scale. For further information, comments or questions, please, contact the CFC PI for this section (C. S. Wong, WongCS@pac.dfo- mpo.gc.ca) or David Wisegarver (wise@pmel.noaa.gov). Additional information on WOCE CFC synthesis may be available at: http://www.pmel.noaa.gov/cfc. ******************************************************************************** Prinn, R. G., R. F. Weiss, P. J. Fraser, P. G. Simmonds, D. M. Cunnold, F. N. Alyea, S. O'Doherty, P. Salameh, B. R. Miller, J. Huang, R. H. J. Wang, D. E. Hartley, C. Harth, L. P. Steele, G. Sturrock, P. M. Midgley, and A. McCulloch, A history of chemically and radiatively important gases in air deduced from ALE/GAGE/AGAGE J. Geophys. Res., 105, 17,751-17,792, 2000. ******************************************************************************** The information below was provided by the CFC PI for this section. WHPO DATA PROCESSING NOTES ========== 18DD9403_1 ========== Date Contact Data Type Data Status Summary -------- ---------- ------------- ------------------------------------------- 07/02/97 Millard CTD DQE Begun with jswift's OK 10/28/97 Freeland CTD/BTL Data are Public Garrett, orig chf. sci. is retired 06/15/98 Millard CTD DQE Report rcvd @ WHPO 09/08/99 Talley SUM/BTL Update Needed, passing along to S. Anderson 10/11/99 Mantyla NUTs/S/O DQE Begun 12/07/99 Muus BTL Reformatted by WHPO See note: NOTES for P15N bottle and summary file changes by D. Muus Sept 30, 1999. p15nahy.txt p15nasu.txt p15nbhy.txt p15nbsu.txt 1. Changed silicate Station 069, Sample 1534, 1751.3db from 0.00 to 141.6. 2. Changed STNNBR "NEWS" to "9991" and STNNBR "FREON" to "9992" per Lynne Talley and Frank Whitney messages Sept 22, 1999. 3. Changed longitude Station 9991 Cast 1 Code BE from 123 degrees to 158 degrees to make all longitude degrees for Station 9991 consistent with date and time. 123 deg was Longitude of first station of p15na. 4. Removed letters "P" and "W" from STNNBRs per Lynne Talley and Frank Whitney messages Sept 22,1999. Left letters on STNNBRs not in bottle data file. 5. Moved all Left-Justified BTLNBRs to Right-Justified. (All were 2nd (shallow) rosette bottles with "S" before numbers to distinguish them from main rosette bottles) p15nbhy.txt: Stations 72, 73 & 74 all cast 2. 6. WOCE SECT PRS01 (old weather station Papa?) listed in summary file with station number P26 but has station number PRS1 in bottle file. Summary file has bottle samples indicated for Casts 5, 6, 7 & 9. Bottle file has bottle data for Casts 4, 5, 6 & 8. Lynne T. questioned what we plan to do with PRS01 data. Probably should go back to originator to be straightened out before we do anything. Left all PRS01 data unchanged in p15na files. 7. Swapped CTDSAL and THETA data columns to match Manual format. 8. Moved PR06 data out of p15nahy.txt into pr06_ihy.txt and p15nasu.txt into pr06_isu.txt to avoid duplicate station numbers after Item 4 above. Summary of PR06 sequence designators: Dates Vessel Ch Sci Status per Web a) Oct 17 - Nov 1, 1991 Endeavor Bellegy WHPO b) Feb 3 - 14, 1992 Tully Whitney WHPO NP c) Mar 26 - Apr 13, 1992 Endeavor Perkin WHPO NP d) Sep 8 - 29, 1992 Tully Whitney WHPO NP (See PR05) e) Feb 26 - Mar 17, 1993 Tully Perkin WHPO NP f) May 14 - Jun 3, 1993 Tully Whitney WHPO NP (See PR05) g) Feb 7 - 21, 1994 Tully Perkin PI h) May 10 - 25, 1994 Tully Whitney WHPO NP (See PR05) i) Sep 6 - Oct 10, 1994 Tully Garrett WHPO (See P15N) Moved to separate PR06 files Oct 5, 1999 j) Feb 7 - 23, 1995 Tully Whitney PI k) May 8 - 26, 1995 Tully Whitney ? l) Aug 22 - Sept 13 1995 Tully Boyd ? m) Feb 19 - Mar 8 1996 Tully Whitney ? n) May 6 - 30 1996 Tully Boyd ? ADDITIONAL NOTES Oct 19, 1999, D. Muus 9. Moved PRS01 data out of p15nahy.txt into prs01_hy.txt p15nasu.txt into prs01_su.txt Awaiting resolution of prs01 cast numbering problem before making final prs01 files for Sep 11, 1994. Addition to summary of PR06 sequence designators: o) Aug 14 - Sep 4 1996 Tully Whitney WHPO (*.XLS files in 9618.ZIP) ADDITIONAL NOTES Dec 6, 1999, D. MUUS 10. Re Item 7 above: When CTDSAL and THETA columns were swapped, I forgot to swap the 7 asterisks denoting QUALT1 numbers. Swapped the 7 "*"s today (Dec. 6, 1999) and placed the corrected p15nahy.txt p15nbhy.txt in /usr/export/ftp/pub/WHPO/MUUS/P15N. 04/04/00 Mantyla NUTs/S/O DQE Report rcvd @ WHPO 04/20/00 Key DELC14 No Data Submitted See Note: Unfortunately, I can provide no new information on the C14 status for cruises P15N and P24. I do know that acquiring data from CS Wong (P15N) has been very difficult. I'll try to investigate. 07/19/00 Wong ALKALI Submitted needs extensive reformatting 07/19/00 Talley CO2/O18 Data Request to C.S. Wong 08/11/00 Muus ALKALI Reformatting Needed D. Bartolocci asked D. Muus to do reformatting Aug 17, 2000 Dave Muus TCO2 and TALK from C.S. Wong files P15NLEG1.dat and P15NLEG2.DAT have been merged with the p15nahy.txt and p15nbhy.txt files. (TCARBN & ALKALI) Uncontaminated Sea Water (USW) data are not included in the .SEA files so the TCO2 and TALK data for USW were put in separate files after conversion to mrgsea usable files: p15naUSWalkco2 & p15nbUSWalkco2 PR06 and PRS01 data from P15NA were recombined and the corresponding TCO2 and TALK data were merged: pr06_ihy.txt pr06_isu.txt "i"is the sequence designator used during my reformatting last year. I am not sure it is still the proper designator. Data discrepancies noted: STA CAST SMPL PRESS P15NA 016 3 all ALKALI present but QUALT1 - 1 052 3 all ALKALI present but QUALT1 - 1 PR06 26 8 117 2800.6 ALKALI missing but QUALT1 - 2 USW 64 2 L113 3.0 ALKALI 2305.9 but QUALT1 - 9 79 3 L126 3.0 ALKALI missing but QUALT1 - 2 96 2 L143 3.0 ALKALI missing but QUALT1 - 2 134 2 L181 3.0 ALKALI missing but QUALT1 - 2 136 2 L183 3.0 CO2&ALK missing but " both 2 138 3 L185 3.0 ALKALI missing but QUALT1 - 2 140 2 L187 3.0 TCARBN missing but QUALT1 - 2 142 2 L189 3.0 CO2&ALK missing but " both 2 08/18/00 Bartolacci ALKALI/TCARBN Data Update btl file reformatted: (tcarbn, alkali, qualt1) Total alkalinity and Dissolved Inorganic Carbon have been merged into P15N_a and P15N_b by D. Muus. In doing so, he removed the PRS01 and PR06 stations from the P15N_a bottle file. This creates a missmatch between the current P15N_a sumfile and the new bottle file, since the sumfile has retained PRS01 (but not PR06). PR06 and PRS01 have been split off into separate sum and bottle files for this cruise and need to be put online. This matter should be rectified, and correct stations be placed in the P15N files before any further events take place on this line. 09/11/00 Bartolacci BTL/SUM Data Merged into BTL file PR06 and PRS01 segments reinserted, see note: 2000.09.11 At the request of J. Swift the PR06 and PRS01 segments of the P15 cruise were reinserted back into the P15 bottle and sumfiles. The table entry for PRS01 and PR06 will be linked to the P15 index.htm page 1. PR06/PRS01 data were obtained from the directory .../p15na/original/2000.07.24_P15N_TALK_DIC_WONG/pr06_ihy.txt .../p15na/original/2000.07.24_P15N_TALK_DIC_WONG/pr06_isu.txt these files were originally extracted by D.Muus these files were inserted into the current online summary file and the previously formatted bottle file of 1999.10.01 by D. Muus. 2. The current online files were moved from: p15nahy.txt to /original/p15nahy_rplcd_2000.09.11.txt p15nasu.txt to /original/p15nasu_rplcd_2000.09.11.txt 3. New complete files were renamed p15nahy.txt and p15nsu.txt 4. Added name/date stamp. 5. Ran sumchk - no errors. 6. Ran wocecvt - with errors corresponding to stations 13, 18, 39. error output stated that following station/cast combinations could not be matched between sumfile and bottle file: PR06 13/3 PR06 18/3 P15 013/3 P15 018/3 P15 039/5 all of these station casts are in both bottle and sum files so interpretation of this output was difficult. 7. Edited CTD file headers to match changes made by D. Muus to summary and bottle files so station designators would match bottle and summary station designators: changed expocode in all files from 18DD9403/1 to 18DD9403_1 removed "W" from all station numbers changed "FREON" in station designator to "9992" as per D. Muus. 8. Ran wctcvt - with errors corresponding to stations 4,13, 39. error output stated that the following station/cast combinations could not be matched between sumfile and ctd file: P15 004/1 P15 013/1 P15 018/2 P15 039/4 all of these station casts are in both ctd and sum files so interpretation of this output was difficult. 9. moved current zipped ctd files from p15nact.zip to original/p15nact_rplcd_2000.09.11.zip moved newly formatted zipfile into p15nact.zip 11/29/00 Wisegarver CFCs DQE Report rcvd @ WHPO 12/11/00 Uribe DOC Submitted See Note: 2000.12.11 File contained here is a CRUISE SUMMARY and NOT sumfile. Documentation is online. 2000.10.11 KJU Files were found in incoming directory under whp_reports. This directory was zipped, files were separated and placed under proper cruise. All of them are sum files. Received 1997 August 15th. 03/15/01 Key DELC14 Measured as per .DOC Funding now available to analyze Got word from Eric this A.M. that he will fund NOSAMS at the rate of 1000/year to analyze previously collected, but unfunded C14 samples. Highest priority will be to fill in Pacific "holes" starting with P14S15S (NOAA), P15N (Wong) and P1 (Japan). Policy decision supported by WOCE SSC. Eric would, if possible, like these data to be included in the atlas. In reality I don't know if this is possible/practical, but I will do everything possible to expedite. Scheduling at NOSAMS will be complicated, but order listed above is the "scientific" priority as of now. 06/22/01 Uribe BTL Website Updated CSV File Added Bottle file in exchange format has been put online. 10/29/01 Muus CFCs Website Updated new cfcs merged into online btl file Merged July 2001 CFCs into bottle file and placed new woce format and exchange format files on web. Made minor modification to Summary file. Changed Quality Code 1 to 9 where appropriate. Notes on P15Na CFC merging Oct 29, 2001. D. Muus 1. New CFC-11 and CFC-12 from: /usr/export/html- public/data/onetime/pacific/p15/p15n/p15na/original/ 20010709_CFC_UPDT_WISEGARVER_P15N_ALL_LEGS/ 20010709.173723_WISEGARVER_P15N_p15n_CFC_DQE.dat merged into SEA files from web Oct 17, 2001. (20000908WHPOSIODMB) for P15Na Prior to merging: Changed all "1"s in QUALT1 to "9"s and then copied QUALT1 to QUALT2. Changed all missing values for DELC14 from -9 to -999.0. 2. Summary file modified by putting Station P13 Cast 1 before Station 13 Cast 2 BE, and putting Station P18 Cast 1 before Station 18 Cast 2 BE. Both were between Cast 2 BE and BO in correct time sequence but wocecvt "skipped" both casts and the exchange conversion duplicated both casts. Now in correct cast sequence but out of sequence for times. Both wocecvt and exchange conversion okay. 3. New exchange file checked using Java Ocean Atlas. 02/04/02 Uribe CTD Website Updated CSV File Added CTD has been converted to exchange and put online. ========== 18DD9403_2 ========== Date Contact Data Type Data Status Summary -------- ---------- ------------- ------------------------------------------- 07/02/97 Millard CTD DQE Begun Leg 2 only 06/15/98 Millard CTD DQE Report rcvd @ WHPO 08/04/00 Kappa data hist Data Update for data hist see P15N 18DD9403_1 Until today these 2 distinct data files were treated as if they were one continuous cruise. 08/18/00 Bartolacci ALKALI/TCARBN Data Update btl file reformatted, see note: Bottle: (tcarbn, alkali, qualt1) Total alkalinity and Dissolved Inorganic Carbon have been merged into P15N_a and P15N_b by D. Muus. In doing so, he removed the PRS01 and PR06 stations from the P15N_a bottle file. This creates a missmatch between the current P15N_a sumfile and the new bottle file, since the sumfile has retained PRS01 (but not PR06). PR06 and PRS01 have been split off into separate sum and bottle files for this cruise and need to be put online. This matter should be rectified, and correct stations be placed in the P15N files before any further events take place on this line. 06/22/01 Uribe BTL Website Updated CSV File Added Bottle file in exchange format has been put online. 10/29/01 Muus CFCs Website Updated new cfcs merged into online btl file Merged July 2001 CFCs into bottle file and placed new woce format and exchange format files on web. Changed Quality Code 1 to 9 where appropriate. Notes on P15Nb CFC merging Oct 19, 2001. D. Muus 1. New CFC-11 and CFC-12 from: /usr/export/html- public/data/onetime/pacific/p15/p15n/p15na/original/ 20010709_CFC_UPDT_WISEGARVER_P15N_ALL_LEGS/ 20010709.173723_WISEGARVER_P15N_p15n_CFC_DQE.dat merged into SEA file from web Oct 17, 2001. (20000817WHPOSIODM) Prior to merging: Changed all "1"s in QUALT1 to "9"s and then copied QUALT1 to QUALT2. Changed all missing values for DELC14 from -9 to -999.0. Found duplicate sample number used for two different bottles: Sta Ca Sample# Bottle# Pressure 111 2 2552 13 1500.4 111 2 2552 12 1749.2 No CFCs taken from either bottle, but TCARBN and ALKALI were measured and the values for Bottle #13 (2325.6 & 2409.9) had been merged into both bottles. Corrected Bottle #12 TCARBN and ALKALI values (2334.5 & 2417.9). Station 108, Cast 9, Sample 2492, Bottle S10 has CTDPRS - -9.0. All other samples also -9. Bottle quality code is 4 "did not trip correctly". CTDSAL quality codes are 2 while all other quality codes are 9. Changed CTDSAL quality codes to 9. 2. New exchange file checked using Java Ocean Atlas. 03/20/02 Bartolacci CTD Update Needed CTD cast numbers do not match SUM file CTD station files for this cruise contain station numbers that do not match those station numbers contained in the summary file. No CTD exchange files have been generated at this time. Station numbers need to be resolved/corrected. 07/02/02 Kappa DOC PDF cruise reports added, text doc updated Added CTD, HYD and CFC Data Quality Reports to the online cruise report. Compiled PDF version with all updates and figures.