METEOR Cruise 41, Leg 3 Vit—ria - Salvador 17 April - 15 May 1998 Cruise Report of the Physical Oceanography Group on Board by Walter Zenk, Sylvia Becker, Johann Jungclaus and Rudolf Link Institut fŸr Meereskunde an der UniversitŠt Kiel Status: 26 August 1998 5 Preliminary Results 5.3 Marine Geoscience M41/3 5.3.1 Physical Oceanography (Walter Zenk, Sylvia Becker, Johann Jungclaus, Rudolf Link) Introduction The World Ocean Circulation Experiment (WOCE) will terminate its observational phase by the end of 1998. This unique oceanographic campaign compassed planning, implementation and coordination of a global network of hydrographic observations and now aims at extensive modeling studies during its analysis, interpretation and synthesis phase in the years to come. The hydrographic work during M41/3 was part of the Deep Basin Experiment (HOGG et al., 1996), a subprogram in Core Project 3 of WOCE. Furthermore, the physical oceanography group on board assisted to collect water samples for other parties on the METEOR, including supplements to the WOCE Hydrographic Program (WHP) tracer network. The equatorward flow of Antarctic Bottom Water (AABW) in the South Atlantic is part of the global thermohaline circulation, jointly with fluxes of Antarctic Intermediate Water (AAIW) and North Atlantic Deep Water (NADW). The Rio Grande Rise at a nominal latitude of 30¡ S represents a natural barrier for the spreading of Antarctic Bottom Water between the Argentine and the Brazil Basin. It is intersected by two deep channels: The Vema Channel (originally called Rio Grande Gap) and the Hunter Channel (ZENK et al., 1993; ZENK et al., 1998). Estimates based on geostrophy and results from moored current meters have demonstrated that more than half of the bottom water export between the two neighboring basins is achieved through the deep Vema Channel (SPEER & ZENK, 1993; HOGG et al., 1998). According to these long-term observations the total northward transport of Antarctic Bottom Water amounts to 6.9 _ 106m3s-1. The contribution of the Hunter Channel (2.3 _ 106m3s-1) is not insignificant (ZENK et al., 1998) but was beyond the scope of this cruise. At a number of locations, WOCE observations have demonstrated a tendency towards increasing bottom water temperatures. In fact, a systematic temperature increase of 30 mK was observed by the METEOR in the Vema Channel near the sill between January 1991 and December 1992. Comparable changes of bottom water properties were never observed before in the Vema Channel since the availability of the first highly accurate CTD records in 1972. The trend towards higher bottom water temperatures has also been documented in comparable, yet unpublished WOCE observations of Brazilian and English groups. According to the latest visit in spring of 1996 the upward trend appeared to be stopped, however, at the end of our cruise we had to revise this view. During M41/3 the physical oceanography group aimed at a new survey of the bottom water properties and distribution by (i) starting a long-term record of variability of water mass characteristics at the sill of the Vema Channel wtih moored instruments and (ii) enlarging the set of highly accurate hydrographic data during cruises. The latter is also expected to serve as an improved input for modeling efforts. Monitoring of bottom water properties will provide more insight into its fluctuations which for a long time have been assumed to be negligible. Methods, data acquisition and reduction A number of observational tools were applied during the cruise. The backbone for hydrographic observations was a CTD (conductivity, temperature, depth (pressure)) recorder in combination with a rosette sampler carrying 21 bottles. An inventory of all CTD stations is given in Tab.X1. Locations of CTD stations are displayed in Figs.X1 and X2. The bottle set was used on 25 stations yielding over 500 water samples. Because of the application of a lowered Acoustic Doppler Profiler (lADCP), to be described later, we used no mechanical bottom finder. Instead, bottom approaches were monitored by a pinger. Our CTD system (Neil Brown MKIIIB, IfM no. NB3) was provided by the IfM based Zentrallabor fŸr Me§technik, a German WOCE unit maintaining high quality instruments including their reliable calibration. The CTD probe was last calibrated in temperature immediately prior to cruise M41/3 on 11/12 March 1998. A post-cruise calibration was performed in summer 1998. We made every effort to calibrate all CTD stations while still on board. 42 salinity twin samples, a subtotal of all the rosette samples, were analyzed by an Autosal salinometer (IfM no AS6). For standardizing we used batch No P129. The resulting 21 pairs of check values were systematically taken from the deepest part of the profiles, i.e. about 25 m above the ground (near-bottom, NB), and from the mixed layer (ML) at the 10 m level. The inter-twin standard deviations of salinity amount to _{0.0009, 0.0019, 0.0015} for {NB, ML, all} levels. Comparable sampling noise during the CTD data acquisition at constant depth while firing bottles is of a similar order _{0.0007, 0.0027, 0.0017}. Quasi-time series of salinity corrections are shown in Fig.X3. Mean salinity corrections for {NB, ML, all} levels ({+1.8, +9.3, +5.5} _ 10-3) are included. No systematic calibration drift could be recognized. Fig.X4 contains corrections as a function of salinity readings. Here, we found a dependence on salinity (conductivity) which needs to be considered in the final calibration. Assuming all ML values taken at the surface, all NB values sampled at 4000 dbar and salinity decreasing linearly with pressure PCTD we can infer a crude preliminary correction for raw salinities SCTD: Scorrected = SCTD + (B _ PCTD + A) (1) with B = -1.85 _ 10-6 dbar-1 and A = 9.2 _ 10-3. In the following text and figures (with the exception of Appendix 1) no salinity correction is applied in this report. Since corrections are relatively tiny, they would not be recognizable in the majority of the salinity graphs shown in this document. Final salinity values are subject to a more careful post-cruise CTD calibration. Lists of all CTD casts with observed in situ temperatures, potential temperatures and salinities at standard depth/pressure values are given in Annex X1. Here, preliminary salinity corrections according to (1) have been taken into account. The latest version of the processing and data reduction software package CTDOK, administered by Thomas MŸller of IfM, was used on a Personal Computer. The processing includes the following sequential software modules: Inspection and graphic editing by hand, maximum lowering speed check to detect pressure spikes, dynamic pressure correction, despiking by a median argument, monotonizing with respect to pressure, minimum lowering speed check, low pass filter run with 19 weights, pre-cruise fine-tune calibration, static pressure-offset correction, interpolation on 2 dbar steps and storage for plotting and export in MATLAB_ binary files (*.mat). During earlier WOCE cruises the same CTD probe was used repeatedly in the Vema Channel and for WHP section work. According to our earlier experiences and after the application of all corrections and the post-cruise calibration, an absolute accuracy of better _ 2 mK in temperature, _0.003 practical salinity units (PSU), and _3 dbar in pressure can be expected. The refurbished on-track observational system DVS of the METEOR was used to collect quasi-continuous near-surface temperature from two sensors of the ship's meteorological station. It was found that the portside thermometer reading lies systematically {0.149 _ 0.050} K below the starboard thermometer of the ship (Fig.X5). Both sensors are mounted 4 m below the surface. An ad-hoc comparison with CTD data from the surface (according to Tab.X1) indicates the portside DVS temperature to be systematically lower by _ 0.3 K (see Fig.11b). Between 21 April and 5 May we collected 34 twin water samples for a calibration check of the ship's thermosalinograph which data also are fed to the DVS system. From the resulting 17 salinity check values we inferred a calibration equation that is valid for April / May 1998: Scorrected = D _ SThermosalinographDisplay + C (2) with D = 1.0054 and C = -0.0211. Four samples of these were collected on passage. Although the latter are supposed to be of slightly lower quality, all samples were equally treated by the indicated least square linear fit (Fig.X6). Preliminary depth profiles for sections were exported from the DVS data bank as well. Due to varying numbers of outliers, depth values were clipped by plausible extrema and subsequently low pass filtered. Until Sta. 229, the CTD/rosette sampler was supplemented by a lowered broad-band Acoustic Doppler Current Profiler (BB lADCP) which was kindly provided by JŸrgen Fischer from IfM Kiel. We expect the obtained vertical current profiles to deliver valuable information on shear as an indicator for enhanced mixing in the benthic boundary layer of the Vema Channel and its northward extension. Due to a technical problem the last lADCP station (no 229) failed to deliver currents. After successful repair, the instrument was not remounted on the rosette sampler. The lADCP log is given in Tab.X4. In addition to the well known problem of the near bottom interference layer, our lADCP measurements suffered from a lack of scattering particles in the intermediate depth ranges of this 'blue water' environment. The dramatic decrease of the received signal amplitude can be seen in the vertical profile of target strength (Fig.X7a, profile 212) below 1000 m. However, the signal strength recovers over the deepest 600 m of the profile, apparently owing to an increase of sediment particle concentration on the Vema Sill. Fig.X7b depicts the raw vertical velocity component (bin 3) over the total duration of the cast. The lowering speeds of 1 ms-1 during downtrace and 1.2 ms-1 during uptrace are generally recovered. However, there is a large data gap between, say, ensemble 700 and 1100 (the bottom-nearest point was approached around ensemble 1300). During uptrace a similar behavior is observed and there are additional periods of near-zero vertical velocities during water sampling stops. These data gaps are also visible in the raw data northward velocity component (Fig.X7c). Near the bottom (around ensemble 1300) the (earth) velocities are predominantly northwards as expected in the deep trough of the Vema Channel. The standard procedure to derive relative velocities is to differentiate individual lADCP profiles vertically, then to average overlapping profiles in depth cells and integrate the resulting mean shear profile from a reference level (FISCHER & VISBECK, 1993). The lADCP is a self-contained instrument without pressure sensor. Its depth is determined by integrating the measured vertical velocity in time. The large data gaps prevented us from calculating reference velocities from time integrals of the baroclinic velocities by our software package so that the data require additional post-cruise processing. (The set of processing programs had been kindly provided by J Fischer.) Relative northward velocities (referenced to the deepest point at 4362 m) are displayed for the deep part of the profile in Fig.X7d (downtrace), and X7e (uptrace). Northward velocities show maximum values between 100 to 200 m above the bottom. They are consistent with earlier findings from moored current meters in the Vema Channel and from numerical modeling. This nose shaped velocity profile with pronounced shear layers above and below the maximum is typical for bottom boundary currents (MERCIER & SPEER 1997; ZENK et al., 1998). The vessel mounted Acoustic Doppler Current Profiler (VM ADCP) operated routinely. It covered approximately the upper 250 m layer. Unfortunately its data flow is still not yet integrated by the ship's own DVS data bank. For topographic surveys we used the multi-beam echosounder Hydrosweep_ of the METEOR. In the subsequent data processing we were kindly supported by the ship's system operator V. Gebhardt. Of special interest were details of the topography of the Vema Sill where IfM mooring V389 was deployed (see Tab.X2, Fig.X8). This area had already been surveyed with Hydrosweep in 1991 during METEOR cruise 15. Fig.X9 shows blow-ups on identical scales of both independent observations from the eastern side of the Vema Sill. They were obtained with the same hardware but with significantly different Hydromap_ software versions. As expected, both maps agree excellently in region with steep topography. In fact, the slope of the shown eastern wall can exceed 25 %. Less agreement in the details can be found on the ground plateau with its minimal slopes. Inaccuracies in depth estimates can shift isobaths horizontally by a few kilometers. At the beginning of the cruise, on Sta. 209 we deployed a current meter mooring (IfM no V389) on the sill of the Vema Channel. Logistical and operational details are given in Fig.X8 and Tab.X2. The current meter rig is designed for a two-year record of temperature and speed fluctuations. The moored CTD recorder (MicroCat_ by Sea Bird, Inc.) has a sampling capacity of over three years. The start of a long-term record of temperature variability of Antarctic Bottom Water with great accuracy was a major goal of the physical oceanography group on board. Hydrographic conditions in the central South Atlantic Here we discuss the water mass stratification on two orthogonal sections at 9¡ W and 24¡ S. We assume the involved selection of hydrographic stations to be representative for the central subtropical South Atlantic. The sections (see Fig.X1) are short in comparison with the WHP network (SIEDLER et al., 1996). Related WOCE sections A9 and A14 are located on 19¡ S and 9¡ W. They were occupied in 1991 and 1995 by METEOR (M15) (SIEDLER & ZENK, 1992) and the French research vessel L'ATALANTE. For the general descriptions of distinctive water masses we depict their characteristic potential temperature salinity (_/S) properties in Fig.X10. For this purpose we have plotted all interpolated (_p = 2 dbar) CTD data from the two sections in one diagram. Tropical surface water (TW) with _ >20¡ C at the top of Fig.X10 shows a tendency to split. Colder, more fresher water was encountered on and to the East of the Middle Atlantic Ridge in the Angola Basin. Its counter part with warmer and saltier surface conditions in the Brazil Basin can be better recognized in Fig.X11. This figure shows the near-surface T/S record from the thermosalinograph (_t = 10 min) on four sections. The higher variability in T/S in the western (Fig.X11b) and the southern (Fig. X11a) regions reflects a number of fronts, more frequently encountered in the open Brazil Basin than in the Angola Basin (Fig.X11b). The frontal structure of surface parameters appears caused by the Brazil Current Front (BCF) as part of the inner recirculation in the Brazil Basin. The colder surface waters (< 25¡ C) on 9¡ W and on its cross point with the 24¡ S section can be interpreted as a signal of the far reaching Benguela Current southwest of the Benguela Angola Front (Fig.X12). Densities, i.e. _t values, at the surface of the central South Atlantic of {(24.3 - 24.5), (24.7 - 24.9)} kg m-3 are typical ranges for the {Brazil, Angola} Current regime in May 1998. Here we note that two subtropical surface water types are separated by a line west of the Middle Atlantic Ridge. The crest region itself has the same T/S properties as the eastern side of the Ridge. We return to the CTD derived _/S diagram in Fig.X10. At temperatures between approxi- mately 10¡ and 16¡ C we find a tight _/S relation which in our case is characteristic for South Atlantic Central Water (SACW) of the main thermocline. Farther down in the water column it is replaced by Antarctic Intermediate Water (AAIW) with its salinity low at < 34.5 (BOEBEL et al., 1997). The next salinity extremum (> 34.86) belongs to the North Atlantic Deep Water (NADW) (ZANGENBERG & SIEDLER, 1998). After crossing the equator it erodes Circumpolar Deep Water (CDW) splitting this lower saline water mass into an upper CDW and a lower CDW type (REID et al., 1977). Towards the West of our 24¡ S section the deepest part of the water column (_ < 2.0¡ C) is occupied by the Antarctic Bottom Water (AABW) (SPEER & ZENK, 1993). Its properties will be discussed in more details in the next paragraph on observations in the Vema Channel. Our presentation of the water mass structure in the _/S diagram (Fig.X10) is paralleled by figures of vertical sections of potential temperature (_) and salinity (S) from the adjunct sections on 9¡ W and 24¡ S (Fig.X13, X14). The low saline tongue of Intermediate Water at 750 m remains unchanged at Smin_34.40 on the zonal section (Fig.X14) while we recognize a well expressed meridional gradient with equatorward increasing salinities on the meridional section (Fig.X13). The thick tongue of North Atlantic Deep Water (S > 34.90) appears to be blocked by the topography of the Middle Atlantic Ridge (Fig.X14). However, at the northern side of the 9¡ W section we cut through a salty tongue of Deep Water (S > 34.90) which we interpret as being deflected eastwards across the Ridge into the Angola Basin by the change of its potential vorticity in the presence of the zonal Vitoria Trindade Ridge a 19¡S (ZANGENBERG & SIEDLER, 1998) and being one source of the Namib Col current (SPEER et al., 1995). Farther South we have traversed the deep Rio de Janeiro Fracture Zone at 23.7¡ S. It allows lower Circumpolar Deep Water with _ _ 2.0¡ C to be exchanged across the Ridge. Its role in the deep circulation of the Angola Basin remains unclear and deserves further efforts. As expected in the Angola Basin, we nowhere found a distinct near-bottom temperature step in vertical profiles as they were seen so clearly in the Brazil Basin. This observation agrees with the known absence of Antarctic Bottom Water in the Angola Basin (SIEDLER et al., 1996). Flow of Antarctic Bottom Water through the Vema Channel The Vema Channel represents the deepest conduit for bottom water of the Rio Grande Rise (HOGG et al., 1982). According to our newest bathymetric survey (Fig. X9b) its depth varies between 4620 and 4640 m. Its northern extension can easily be followed by tracking the 4000 m isobath on the digital topographic map by SMITH & SANDWELL (1997) displayed in Fig.X15. We have included positions of the two hydrographic sections: 'Vema Channel' (VC) across the Vema Sill and the section 'Vema Extension' (VE) at the northeastern corner. Both sections are shown on different horizontal scales (section VC in Fig.X16, section VE in Fig.X17). Mooring V389 that was deployed 21 May 1998 (Fig.X8; Tab.X2) lies 4 km upstream between CTD Sta 210 and 211 (Fig.X16). Its projection can be seen in the temperature sections of Fig.X16. Results from the self-recording instruments are not expected before the year 2000. Water masses found in the Vema Channel (SPEER & ZENK, 1993) resemble those described in the last paragraph for the central South Atlantic. They are stacked in the well known fashion from the top to the bottom: Tropical surface Water and South Atlantic Central Water of the main thermocline, low saline Antarctic Intermediate Water at 900 m, upper and lower Circumpolar Deep Water penetrated by more saline North Atlantic Deep Water (1500 - 3500 m) and closest to the ground Antarctic Bottom Water with _ < 2¡ C including its coldest compound Weddell Sea Deep Water (_ < 0.2¡ C, see Fig.X16, X17 for pressures larger 2500 dbar). Water properties of the Vema Channel and in the Vema Extension below approximately 4100 m can be studied in more detail in the blown-up _/S diagram of the deepest stations (stat. no. 212 and 215) in Fig.X18. The form of the vertical profile (Fig.X19) demonstrates the well mixed bottom boundary layer in the channel. Its thickness is of O(140 - 180) m. Thick bottom boundary layers are a unique feature of narrow oceanic passages with bottom water flow (HOGG et al., 1982; JUNGCLAUS & VANICEK, 1998). Frictionally driven secondary circulation drive relatively warm waters down the (here western) channel wall leading to hydrostatic unstable conditions and intense vertical mixing. On the eastern side of the Vema Sill relatively cold water is transported upslope enhancing the stratification there. Thus, the coldest waters are trapped and shielded on the eastern side of the channel (Fig.X16) both by a pronounced thermocline and the channel wall (Fig.X9). Summary and concluding remarks We summarize our preliminary results as follows: _ Earlier observations (Fig.X20; ZENK & HOGG, 1996; HOGG & ZENK, 1997) showing increasing bottom temperatures and salinities in the Vema Channel were confirmed. Compared with 1996, the lowest potential temperature in the Vema Sill rose again by 20 mK (Tab.X3). A pertinent salinity increase of 0.007 was directly observed from salinity samples taken by the rosette sampler closest to the bottom from two METEOR expeditions (M36 in 1996 and M41). No change in the density stratification appears to be associated with this change in _/S properties. However, final salinity calibration of the CTD records remains subject of the post-cruise calibration. _ Between the Vema Sill and the Vema Extension (_ 27¡ S, 34¡ W, see Fig.X15) Weddell Sea Bottom Water with _ _ 0.2¡ C is guided and isolated from mixing with warmer Lower Circumpolar Deep Water for over 700 km by the ca–on-dominated topography. Its temperature rises from _ = -0.136 to -0.098, i.e. by only 38 mK, salinity increases by barely 0.005 practical salinity units (34.670 _ 34.675). In how far these temperature and salinity increases are caused by turbulent diffusion and/or by advected modulations of the source waters must remain open, since they both can be of the same order. _ Further mixing takes place northeast of the funnel-shaped end of the Vema Extension in the deep Brazil Basin with depths > 4800 m (upper right hand corner in Fig.X15). Some additional 1300 km downstream at Sta 218 (see Fig.X1) the tongue of Weddell Sea Deep Water, the coldest subtype of Antarctic Bottom Water, has been totally eroded. There we found bottom values of _ = 0.440¡ C and S = 34.716. Hence, the horizontal bottom temperature and salinity gradients between the exit of the Vema Extension and the inner Brazil Basin increase significantly due to turbulent mixing in the absence of a shielding ca–on. They are one order of magnitude larger, {550 mK, 0.04}/1300 km in {_, S} then in the Vema Channel itself. _ A long-term mooring carrying current meters (Fig.X8; Tab.X2), thermistor chains and a CTD recorder for the observation of property fluctuations was deployed without any problems. 9. References BOEBEL, O., C. SCHMID and W. ZENK (1997): Flow and recirculation of Antarctic Intermediate Water across the Rio Grande Rise. J. Geophys. Res., 102 (C9), 20,967-20,986. FISCHER, J. and M. VISBECK (1993): Deep velocity profiling with self-contained ADCPs. J. Atm. Ocean Techn., 10, 764-773. HOGG, N.G., P. BISCAYE, W. GARDNER, and W.J. SCHMITZ, jr. (1982): On the transport and modification of Antarctic Bottom Water in the Vema Channel. J. Mar. Res., 40 (suppl.), 231Ð263. HOGG, N.G., W. BRECHNER OWENS, G. SIEDLER und W. ZENK (1996): Circulation in the Deep Brazil Basin. In: Wefer, G., W.H. Berger, G. Siedler and D.J. Webb (Eds.): The South Atlantic: Present and Past Circulation. Springer Verlag, Berlin, Heidelberg, 249-260. HOGG, N., G. SIEDLER und W. ZENK (1998): Circulation and variability at the southern boundary of the Brazil Basin. J. Phys. Oceanogr. (in press) HOGG, N. and W. ZENK (1997): Long-period changes in the bottom water flowing through Vema Channel. J. Geophys. Res. 102 (C7) 15,639-15,646. JUNGCLAUS, J.H. und M. VANICEK (1998): Frictionally modified flow in a deep ocean channel: Application to the Vema Channel. J. Geophys. Res. (in press) MERCIER, H. and K. SPEER (1997): Transport of bottom water in the Romanche Fracture Zone and the Chain Fracture Zone. J. Phys. Oceanogr. (accepted). REID, J.L., W.D. NOWLIN and W.C. PATZERT (1977): On the characteristics and circulation in the southwestern Atlantic Ocean. J. Phys. Oceanogr., 7, 62Ð91. SIEDLER, G. und W. ZENK (1992): WOCE SŸdatlantik 1991, Reise Nr. 15, 30. Dezember 1990 - 23. MŠrz 1991. METEOR-Berichte, UniveristŠt Hamburg, 92-1, 126 S. SIEDLER, G., T.J. M†LLER, R. ONKEN, M. ARHAN, H. MERCIER, B.A. KING and P.M. SAUNDERS (1996) The zonal WOCE sections in the South Atlantic. In: Wefer, G., W.H. Berger, G. Siedler and D.J. Webb (Eds.): The South Atlantic: Present and Past Circulation. Springer Verlag, Berlin, Heidelberg, 83- 104. SPEER, K.G., G. SIEDLER and L. TALLEY (1995): The Namib Col Current. Deep-Sea Res. I, 42 (11/12), 1933-1950. SMITH, W.H.F. and D.T. SANDWELL (1997): Global sea floor topography from satellite altimetry and ship depth soundings. Science, 277, 1956-1962. SPEER, K.G. und W. ZENK (1993): The flow of Antarctic Bottom Water into the Brazil Basin. J. Phys. Oceanogr. 23, 2667-2682. ZANGENBERG, N. and G. SIEDLER (1998): Path of the North Atlantic Deep Water in the Brazil Basin. J. Geophys. Res., 103 (C3), 5419-5428. ZENK, W., K.G. SPEER und N.G. HOGG (1993): Bathymetry at the Vema Sill. Deep-Sea Res., 40 (9), 1925- 1933. ZENK, W., G. SIEDLER, B. LENZ and N.G. HOGG (1998): Antarctic Bottom Water Flow through the Hunter Channel. J. Phys. Oceanogr. (submitted). ZENK, W. und N.G. HOGG (1996): Warming trend in Antarctic Bottom Water flowing into the Brazil Basin. Deep-Sea Res. I, 43 (9), 1461-1473. Tab. X1: Inventory of CTD stations Station No/ Profile No GeoB No Date 1998 Time UTC Lat ¡S Long ¡W z(m) Bridge Log near surface T(¡C) at depth (m) T(¡C) pmax(dbar) lADCP y/n Remarks 208 / 01 5101-1 20/04 16:44 28 26.25 40 54.59 4388 23.94 0.36 4421 y Test station 210 / 02 5103-1 21/04 17:42 31 11.84 39 23.86 4614 21.04 0.22 4666 y Vema Channel 211 / 03 5104-1 21/04 21:59 31 12.04 39 21.02 4574 21.15 0.22 4630 y 212 / 04 5105-1 22/04 01:42 31 12.02 39 18.90 4475 21.16 0.20 4510 y 213 / 05 5106-1 22/04 05:56 31 12.03 39 16.02 4066 21.44 1.20 4098 y 214 / 06 5107-1 23/04 19:16 26 53.99 33 54.96 3798 23.59 1.60 3812 y Vema Extension 215 / 07 5108-1 23/04 23:53 26 41.97 34 14.02 4783 23.65 0.28 4862 y 216 / 08 5109-1 24/04 07:06 26 17.99 34 56.16 4341 24.35 0.30 4388 y 217 / 09 5110-1 24/04 16:45 25 53.88 35 38.89 4215 25.03 0.41 4241 y 218 / 10 5111-1 28/04 10:14 23 48.81 20 00.03 5215 25.71 0.90 5284 y 24¡S 219 / 11 5112-1 29/04 10:07 23 49.59 16 16.34 3874 25.19 1.50 3901 y 220 / 12 5113-1 30/04 02:58 23 40.12 15 00.02 3853 25.01 2.14 3885 y 221 / 13 5114-1 30/04 11:46 24 09.95 13 59.86 3171 24.75 2.61 3204 y 225 / 14 5118-1 01/05 08:17 24 10.81 13 23.07 2741 24.61 2.71 2778 y 226 / 15 5119-1 01/05 15:57 24 10.08 12 18.11 3910 24.46 2.49 4008 y 229 / 16 5122-1 02/05 10:56 24 10.25 11 07.95 3737 24.31 2.41 3760 y 231 / 17 5124-1 02/05 23:35 24 09.96 09 53.92 4322 23.91 2.43 4375 n 232 / 18 5125-1 03/05 06:55 24 09.91 09 00.19 4462 23.68 2.44 4523 n 9¡W 233 / 19 5126-1 03/05 19:00 22 23.96 08 59.96 4192 24.04 2.40 4231 n 234 / 20 5127-1 04/05 03:51 21 12.10 09 00.15 3941 24.34 2.38 3878 n 235 / 21 5128-1 04/05 13:03 20 00.03 09 00.09 3959 23.93 2.40 3951 n 236 / 22 5129-1 04/05 21:48 18 59.98 09 46.23 3838 24.46 2.43 3857 n 19¡S 236 / 23 5129-2 05/05 00:57 18 59.98 09 46.20 3840 24.45 13.14 250 n 243 / 24 5136-3 07/05 22:22 19 22.00 12 42.67 4536 24.69 3.48 1500 n 248 / 25 5141-1 09/05 18:30 19 05.75 17 15.12 3453 25.62 3.65 1502 n Tab. X2: Mooring activities Sta. IfM CTD Date Latitude Longitude Depth Ref Instr. Instr. Remarks No VNo Sta/Prof 1998 S W (m) No Type S/N 209 389 {210/2- 21APR 31¡14.30' 39¡20.00' 4580 - WD 2266 ARGOS, no recept. d. deploym. 212/4} 389101 ThCh 1295/ nom recorder depth 4090 m 1960 i.e. 490 m above ground 11 sensors, 20 m apart 389102 AVTP 11442 nominal depth 4310 m i.e. 270 m above ground 389103 ThCh 1296/ nom recorder depth 4312 m 1961 i.e. 268 m above ground 11 sensors, 20 m apart 389104 AVTP 11348 nominal depth 4528 m i.e. 52 m above ground 389105 MiCat 206 nominal depth 4529 m i.e. 51 m above ground - AR 428 48 m above ground Abbreviations AVTP Anderaa Current Meter incl. pressure sensor ThCh Aanderaa Thermistor Chain , recorder / chain MiCat MicroCat moored CTD by SeaBird, Inc. WD WatchDog bouy built at IfM Kiel AR Acoustic Release by MORS Tab X3: Near-bottom CTD and salinometer values from the Vema Sill, 1972 - 1998 (acc. to ZENK & HOGG, 1996; HOGG & ZENK, 1997). Expedition Sta. Pro. _ Acc.T SCTD SCTD SSali Acc.S mm/yy No No ¡C mK raw corr No 1 2 3 __________________________________________________________________________________________ Cato 11/72 14 -0.175 --------------------------------------------------------------------------------------------------------------------------------------- Geosecs 11/72 59 -0.180 --------------------------------------------------------------------------------------------------------------------------------------- CHAIN 4/74 4 -0.188 --------------------------------------------------------------------------------------------------------------------------------------- ATLANTIS II 10/79 76 -0.192 --------------------------------------------------------------------------------------------------------------------------------------- ATLANTIS II 5/80 112 -0.181 --------------------------------------------------------------------------------------------------------------------------------------- METEOR 15 1/91 49 47 -0.185 _2 --------------------------------------------------------------------------------------------------------------------------------------- METEOR 22 12/92 43 -0.155 --------------------------------------------------------------------------------------------------------------------------------------- COROAS I ¤ 3/93 24 -0.140 -------------------------------------------------------------------------------------------------------------------------------------- COROAS II ¤ 3/94 -0.134 --------------------------------------------------------------------------------------------------------------------------------------- POLAR- STERN 10/94 128 31 -0.158 _2 34.655 34.683 34.683 ./. --------------------------------------------------------------------------------------------------------------------------------------- METEOR 34 3/96 49 5 -0.156 _2 34.657 34.665 34.6649 34.6651 34.6637 _0.003 --------------------------------------------------------------------------------------------------------------------------------------- METEOR 41 4/98 212 4 -0.136 _2 34.670 34.6718 34.6730 34.6724 ./. _0.003 ________________________________________ ¤ Kindly provided by Y. Ikeda, University of Sao Paulo. Tab X4a: LADCP Log Pr. No. Stat No. LADCP Start (UTC) Tiefe (m) Date (Start, End) yyyy,mm,dd yyyy,mm,dd Time, down 10m. (CTD Prot) hh,mm,ss (UTC) Posi., down 10m (CTD Prot) gg,mm.mm gg,mm.mm Posi., down 10m (DVS Stream ) gg,mm.mmm gg,mm.mmm Time, up 10m. Start hh,mm,ss Posi, up 10m (CTD Prot) gg,mm.mm gg,mm.mm Posi, up 10m (DVS Stream ) gg,mm.mmm S gg,mm.mmm Time, up 10m End (DVS) hh,mm,ss Posi, up 10m (DVS,End ) gg,mm.mmm S gg,mm.mmm 1 208 15,37 4387 1998,04,20 16,46,35 28,26.34 S 40,54.60 W Wrong time in protocol 19,43,35 28,26.48 S 40,54.69 W 2 210 17,24,4 8 4611 1998,04,21 17,45,05 31,11.99 S 39,23.93 W 31,11.987 S 39,23.928 W 20,38,40 31,12.11 S 39,23.79 W 31,12.108 S 39,23.784 W 20,41,40 31,12.152 S 39,23.812 W 3 211 21,36,5 4 4574 1998,04,21 1998,04,22 22,02,13 31,12.04 S 39,21.01 W 31,12.003 S 39,21.055 W 00,43,45 31,12.27 S 39,21.02 W (End) 31,12.258 S 39,20.989 W 00,47,45 31,12.263 S 39,21.019 4 212 -ÕÕ- 4475 1998,04,22 01,47,12 31,12.06 S 39,18.88 W 31,12.057 S 39,18.872 W 04,40,54 31,12.05 S 39,19.13 W (End) 31,12.027 S 39,19.121 W 04,43,45 31,12.046 S 39,19.132 W 5 213 -ÕÕ- 4065 1998,04,22 05,58,37 31,12.02 S 39,16.00 W 31,12.019 S 39,16.008 W 08,20,00 31,11.98 S 39,15.98 W (Start) 31,11.985 S 39,15.978 W 08,23,15 31,12.000 39,15.968 6 214 19,09,1 9 3784 1998,04,23 19,21,38 26,53.99 S 33,54.96 W 26,53.943 S 33,54.934 W 21,48,03 26,53.97 S (S) 33,55.00 W 26,53.95 S (E) 33,54.99 W 26,53.972 S 33,55.007 W 21,51,07 26,53.949 S 33,54.994 W 7 215 ? 4785 1998,04,23 1998,04,24 23,56,07 26,41.96 S 34,14.01 W 26,41.956 S 34,14.005 W 02,59,19 26,41.98 S (S) 34,14.00 W 26,42.00 S (E) 34,14.02 W 26,41.978 S 34,14.001 W 03,02,21 26,41.996 S 33,14.019 W Tab X4b: LADCP Log (continued) Pr. No. Stat No. LADCP Start (UTC) Tiefe (m) Date (Start, End) yyyy,mm,dd yyyy,mm,dd Time, down 10m. (CTD Prot) hh,mm,ss (UTC) Posi., down 10m (CTD Prot) gg,mm.mm gg,mm.mm Posi., down 10m (DVS Stream ) gg,mm.mmm gg,mm.mmm Time, up 10m. Start hh,mm,ss Posi, up 10m (CTD Prot) gg,mm.mm gg,mm.mm Posi, up 10m (DVS Stream ) gg,mm.mmm S gg,mm.mmm Time, up 10m End (DVS) hh,mm,ss Posi, up 10m (DVS,End ) gg,mm.mmm S gg,mm.mmm 8 216 06,55,4 1 4350 1998,04,24 07,09,27 26,18.00 S 34,56.17 W 26,17.995 S 34,56.165 W 09,50,40 26,18.00 S (A) 34,55.99 W 26,18.03 S (E) 34,55.95 26,18.001 S 34,55.988 W 09,53,41 26,18.030 S 34,55.950 W 9 217 ? 4190 1998,04,24 16,47,49 25,53.97 S 35.38.88 W 25,53.965 S 35,38.881 W 19,26,15 25,54.00 S (A) 35,39.01 W 25,53.99 S (E) 35,39.01 W 25,53.996 S 35,39.005 W 19,29,15 25,53.986 S 35,39.014 W 10 218 09,58,0 5 5215 1998,04,28 10,17,19 23,48.93S 20,00.01W 23,48.904 S 20,00.009 W 13,31,27 23,48.95 S 19,59.78W(A) 23,48.96S 19,59.75W(E) 23,48.950 S 19,59.774 W 13,34,29 23,48,962 19,59.756 11 219 09,57,4 3 3860 1998,04,29 10,09,49 23,49.57 S 16,16.34 W 23,49.570 S 16,16.333 W 12,38,38 23,49.57 S 16,16.34 W(A) 23,49.57 S 16,16.33 W (E) 23,49.571 S 16,16,339 W 12,41,42 23,49.580S 16,16.320W 12 220 02,43,2 8 3850 1998,04,30 03,01,14 23,40.18 S 15,00.09 W 23,40.180 S 15,00.090 W 05,20,38 23,40.21 S 14,59.94 W(A) 23,40.21 14.59.94W (E) kein DVS! 05,30,55 kein DVS 13 221 11,23,0 9 3130 1998,04,30 11,49,45 24,09.97 S 13,59.81 W 24,09.972 S 13.59.817 W 13,54,48 24,09,88 S 13,59.56 W 24,09,88 S 13,59,55 W 24,09,876 S 13,59.559 W 13,57,56 24,09.881 S 13,59.546 W 14 225 08,05,0 8 2740 1998,05,01 08,19,59 24,10.83 S 13,23.07 W 24,10.827 S 13,23.074 W 10,13,18 24,10.77 S 13,23.01 W 24,10.78 S 13,23,07 W 24,10.767 S 13,23.005 W 10,16,27 24,10.777 S 13,23.036 W 15 226 15,25,0 2 3865 1998,05,01 16,02,21 24,10,05 S 12,18.01 W 24,10.045 S 12,18.014 W 18,30,38 24,10.05 S 12,17.86 W 24,10.04 S 12,17.85 W 24,10.767 S 13,23.005 W 18,33,38 24,10.041 S 12,17.852 W List of Figure Captures Figure X1: Location of all CTD station (*). Hydrographic work was equally split between Vema Channel, Vema Extension, and sections on 24¡ S and 9¡ W. For details see Tab X1. Figure X2: CTD station (*) distribution in the area of the Vema Sill. Location (0) denotes the position of IfM mooring V-289. For details see Tab X1 and X2. Figure X3: Comparison of displayed CTD data and their bottle check values as a function of station number or time. The upper curve (*) contains all cases from the mixed layer at 10 m depth. The lower curve (o) denote check values from the deepest level, i.e._ 20 m above the sea bed. No drift or calibration shifts are visible. Figure X4: Comparison of displayed CTD data and their bottle check values as a function of salinity. For symbols see Fig X3. Figure X5: Comparison of the two sea surface thermometers of the meteorological station METEOR. Data were recorded by the DVS system. Sensors show a bias of O(0.15¡ C). Figure X6: Comparison of surface salinities displayed by the DVS system with salinity check values from water samples taken immediately behind the thermosalinograph chamber in the bow of METEOR. Figure X7: Sample plots of the lowered Acoustic Doppler Current Profiler (lADCP) from CTD Sta 212 in the Vema Channel. Note the bottom intensified current profiles (d and e) which indicate the northward transport of Antarctic Bottom Water (AABW) across the Vema Sill. For further details see text. Figure X8: Design of IfM mooring V-389 which was moored in the Vema Channel. For details see Tab.X2. Figure X9: Topographic charts from the eastern side of the Vema Sill taken in January 1991 during METEOR cruise M15 (a) and during METEOR cruise M41 (b) in April 1998. Figure X10: Diagram of all pairs of salinity (S) and potential temperature (_) from Sections at 24¡ S and 9¡ W. Data were interpolated in 2 dbar steps prior to plotting. Abbreviations: TW - Tropical Surface Water, SACW - South Atlantic Central Water, AAIW - Antarctic Intermediate Water, NADW - North Atlantic Deep Water, CDW - Circumpolar Deep Water (u - upper, l - lower), AABW - Antarctic Bottom Water. Diagonal lines of equal densities are referenced to the surface (__ / kg m-3). Figure X11: DVS plots of surface temperatures and salinities on various track lines (see top of graphs). In (a) we have included 10 m CTD temperature values. They appear to ly systematically above the two ship's own surface thermometer readings. See also Fig X5. Figure X12: Diagram of all pairs of salinity and temperature from the surface of Sections at 24¡ S (+ and *) and 9¡ W (+ with o) recorded by the DVS system. Values * and + differ by their location East or West of 18¡ W. Note that data feature two clusters. _t lines ( kg m-3) are overlaid. Figure X13: Salinity (a) and potential temperature (b) sections along 9¡ W in the deep Angola Basin east of the Middle Atlantic Ridge. The distribution of water masses is discussed in the text. Note that no water with _ < 2.0¡ C reaches the Angola Basin, i.e. Antarctic Bottom Water in absent. Figure X14: Salinity (a) and potential temperature (b) sections along 24¡ S. The center of the Middle Atlantic Ridge (MAR) is situated at _ 13.5¡ W. Note the drastic differences between the stratification on the eastern side, i.e. in the Angola Basin and in the Brazil Basin on the western side of the MAR. North Atlantic Deep Water features a deep front preventing this water mass from penetrating into the Angola Basin. The western abyssal is filled with Antarctic Bottom Water (_< 2¡ C). No such water is present in the eastern abyssal. Figure X15: Topographic map of the Vema Channel and its northeastern extension. The 4000 m isobath is an optimal indicator for the channelized spreading of Antarctic Bottom Water (_ < 2¡ C) while filling the deep Brazil Basin. Figure X16: Salinity (a) and potential temperature (b) sections from the Vema Sill below 2500 m. In the right subfigure we have included the position and length of IfM mooring V-389 (see Tab X2). Note the asymmetric horizontal property distribution in the range below _3800 m. For details see text.. Figure X17: Sections as in Fig.X14, however from the Vema Extension. Note the isolated deep channel that prevents Antarctic Bottom Water to be mixed more rapidly with its surrounding water masses then farther north in the inner Brazil Basin. Figure X18: Diagram of potential temperature vs. salinity (_/S) from Sta 212 (+) and 215 (o) from the Vema Sill (see Figs.X1 and X2) and from the Vema Extension (see Fig.X1). Figure X19: Bottom oriented profiles of potential temperature from section (a) at the Vema Channel and (b) the Vema Extension. Note the homogenized temperature on the sill also see in Fig.X17. Figure X20: Long-term CTD temperature time series from the Vema Channel. The newest data point from M41 shows again increased temperatures. In fact, the latest value of _min = -0.136¡ C measured on Sta 212 (see Figs.X2 and X9) is among the highest in the total time series from the sill region in the Vema Channel. ANNEX X1 Distribution of hydrographic parameters on standard pressure levels from all CTD stations taken during cruise M41/3. Columns represent pressure (p), in situ temperature (T), potential temperature (_) and salinity (S) for each station. Considerations on data accuracies are given in the text. Station 208 Profil 01 Station 210 Profil 02 40¡ 54.59 W 28¡ 26.25 S 39¡ 23.86 W 31¡ 11.84 S 20.04.1998 UTC 16:44 4388 m 21.04.1998 UTC 17:42 4614 m p dbar T ¡C _ ¡C S p dbar T ¡C _ ¡C S 2.0 23.911 23.911 36.554 4.0 21.070 21.070 35.754 10.0 23.912 23.910 36.551 10.0 21.027 21.025 35.760 20.0 23.908 23.904 36.551 20.0 20.983 20.979 35.767 50.0 22.920 22.910 36.393 50.0 20.628 20.619 36.008 75.0 19.622 19.608 36.159 75.0 17.265 17.252 35.763 100.0 18.548 18.531 36.083 100.0 16.030 16.014 35.669 150.0 16.836 16.811 35.830 150.0 15.043 15.020 35.589 200.0 15.487 15.456 35.569 200.0 14.338 14.309 35.490 250.0 14.667 14.630 35.467 250.0 13.936 13.900 35.427 300.0 14.590 14.545 35.534 300.0 13.551 13.508 35.386 350.0 13.504 13.454 35.337 350.0 12.725 12.678 35.228 400.0 12.769 12.714 35.222 400.0 11.484 11.433 35.024 450.0 11.689 11.631 35.051 450.0 10.298 10.244 34.868 500.0 10.307 10.247 34.855 500.0 9.136 9.080 34.714 600.0 8.122 8.060 34.598 600.0 6.501 6.452 34.397 700.0 6.434 6.370 34.426 700.0 5.154 5.097 34.281 800.0 5.302 5.235 34.349 800.0 4.579 4.516 34.279 900.0 4.436 4.366 34.329 900.0 4.005 3.938 34.281 1000.0 3.830 3.756 34.338 1000.0 3.701 3.628 34.325 1500.0 3.014 2.906 34.628 1500.0 2.859 2.753 34.626 2000.0 3.528 3.368 34.922 2000.0 3.240 3.084 34.886 2500.0 3.202 2.998 34.944 2500.0 3.112 2.910 34.936 3000.0 2.878 2.630 34.928 3000.0 2.751 2.506 34.922 3500.0 1.186 0.927 34.769 3500.0 2.140 1.856 34.869 4000.0 0.504 0.214 34.698 4000.0 0.950 0.646 34.727 4430.0 0.364 0.032 34.682 4500.0 0.207 -0.128 34.675 4666.0 0.220 -0.133 34.673 Station 211 Profil 03 Station 212 Profil 04 39¡ 21.02 W 31¡ 12.04 S 39¡ 18.90 W 31¡ 12.02 S 21.04.1998 UTC 21:59 4574 m 22.04.1998 UTC 01:42 4475 m p dbar T ¡C _ ¡C S p dbar T ¡C _ ¡C S 2.0 21.183 21.183 35.768 2.0 21.129 21.128 35.780 10.0 21.177 21.175 35.764 10.0 21.143 21.141 35.773 20.0 21.056 21.052 35.757 20.0 21.069 21.066 35.762 50.0 20.703 20.694 36.009 50.0 20.679 20.670 35.985 75.0 17.446 17.433 35.753 75.0 17.478 17.466 35.833 100.0 16.247 16.231 35.708 100.0 15.957 15.941 35.673 150.0 15.126 15.103 35.597 150.0 15.117 15.094 35.597 200.0 14.533 14.503 35.521 200.0 14.572 14.542 35.541 250.0 13.975 13.939 35.441 250.0 14.141 14.105 35.476 300.0 13.476 13.433 35.370 300.0 13.504 13.462 35.376 350.0 12.539 12.492 35.198 350.0 12.560 12.513 35.203 400.0 11.342 11.292 35.010 400.0 11.507 11.455 35.039 450.0 10.324 10.270 34.867 450.0 10.421 10.367 34.879 500.0 9.292 9.235 34.720 500.0 8.749 8.695 34.640 600.0 6.939 6.882 34.459 600.0 6.665 6.609 34.408 700.0 5.461 5.402 34.314 700.0 5.354 5.295 34.322 800.0 4.550 4.487 34.262 800.0 4.477 4.415 34.269 900.0 4.086 4.018 34.292 900.0 4.118 4.050 34.298 1000.0 3.712 3.639 34.330 1000.0 3.673 3.600 34.322 1500.0 2.877 2.770 34.616 1500.0 2.877 2.771 34.613 2000.0 3.211 3.055 34.879 2000.0 3.165 3.010 34.862 2500.0 3.096 2.895 34.938 2500.0 3.098 2.896 34.936 3000.0 2.776 2.530 34.923 3000.0 2.777 2.531 34.919 3500.0 2.188 1.903 34.874 3500.0 2.223 1.938 34.873 4000.0 1.275 0.962 34.772 4000.0 1.378 1.062 34.781 4500.0 0.205 -0.129 34.674 4500.0 0.198 -0.137 34.672 4630.0 0.217 -0.132 34.674 4528.0 0.201 -0.136 34.674 Station 213 Profil 05 Station 214 Profil 06 39¡ 16.02 W 31¡ 12.03 S 33¡ 54.96 W 26¡ 53.99 S 22.04.1998 UTC 05:56 4066 m 23.04.1998 UTC 19:16 3798 m p dbar T ¡C _ ¡C S p dbar T ¡C _ ¡C S 2.0 21.412 21.412 35.772 2.0 23.566 23.565 36.051 10.0 21.419 21.417 35.764 10.0 23.569 23.567 36.046 20.0 21.233 21.229 35.754 20.0 23.565 23.560 36.040 50.0 20.857 20.848 35.957 50.0 22.402 22.392 36.006 75.0 17.798 17.785 35.786 75.0 20.422 20.407 36.249 100.0 16.425 16.409 35.754 100.0 18.757 18.739 36.061 150.0 15.241 15.218 35.623 150.0 16.584 16.559 35.784 200.0 14.635 14.605 35.548 200.0 15.157 15.126 35.553 250.0 14.030 13.993 35.437 250.0 14.602 14.564 35.556 300.0 13.494 13.451 35.367 300.0 14.257 14.213 35.515 350.0 12.650 12.602 35.212 350.0 13.643 13.593 35.406 400.0 11.802 11.750 35.083 400.0 12.363 12.310 35.172 450.0 10.464 10.410 34.889 450.0 11.192 11.136 34.979 500.0 9.098 9.042 34.703 500.0 10.308 10.248 34.865 600.0 6.836 6.779 34.449 600.0 7.704 7.643 34.560 700.0 5.380 5.322 34.326 700.0 6.150 6.088 34.409 800.0 4.577 4.515 34.288 800.0 4.847 4.782 34.324 900.0 4.169 4.101 34.316 900.0 4.099 4.031 34.325 1000.0 3.643 3.571 34.330 1000.0 3.601 3.529 34.364 1500.0 3.109 3.000 34.664 1500.0 2.872 2.765 34.687 2000.0 3.176 3.021 34.870 2000.0 2.834 2.684 34.852 2500.0 3.093 2.892 34.934 2500.0 2.903 2.705 34.927 3000.0 2.786 2.540 34.924 3000.0 2.673 2.430 34.922 3500.0 2.288 2.001 34.882 3500.0 2.262 1.976 34.886 4000.0 1.378 1.062 34.786 3820.0 1.605 1.302 34.815 4096.0 1.247 0.925 34.771 Station 215 Profil 07 Station 216 Profil 08 34¡ 14.02 W 26¡ 41.97 S 34¡ 56.16 W 26¡ 17.99 S 23.04.1998 UTC 23:53 4783 m 24.04.1998 UTC 07:06 4341 m p dbar T ¡C _ ¡C S p dbar T ¡C _ ¡C S 2.0 23.629 23.629 36.075 2.0 24.313 24.312 36.004 10.0 23.632 23.630 36.076 10.0 24.327 24.325 36.016 20.0 23.633 23.628 36.075 20.0 24.323 24.319 36.013 50.0 22.641 22.631 36.237 50.0 22.340 22.330 36.384 75.0 20.524 20.510 36.221 75.0 20.277 20.263 36.264 100.0 19.303 19.285 36.155 100.0 19.045 19.027 36.091 150.0 17.544 17.518 35.864 150.0 17.066 17.041 35.784 200.0 16.135 16.103 35.663 200.0 16.044 16.012 35.632 250.0 14.920 14.882 35.490 250.0 14.994 14.956 35.493 300.0 14.927 14.881 35.588 300.0 14.322 14.277 35.428 350.0 13.621 13.571 35.327 350.0 13.415 13.366 35.280 400.0 12.716 12.661 35.199 400.0 12.337 12.283 35.118 450.0 11.631 11.573 35.038 450.0 11.551 11.493 35.013 500.0 10.656 10.594 34.914 500.0 10.404 10.344 34.862 600.0 8.254 8.191 34.615 600.0 7.900 7.838 34.570 700.0 6.374 6.310 34.430 700.0 5.961 5.899 34.387 800.0 5.005 4.940 34.326 800.0 4.701 4.638 34.319 900.0 4.210 4.141 34.329 900.0 4.169 4.100 34.337 1000.0 3.601 3.529 34.359 1000.0 3.740 3.667 34.378 1500.0 2.910 2.803 34.685 1500.0 3.192 3.082 34.727 2000.0 3.277 3.120 34.929 2000.0 3.380 3.222 34.938 2500.0 3.002 2.802 34.939 2500.0 3.051 2.850 34.941 3000.0 2.755 2.509 34.927 3000.0 2.754 2.509 34.924 3500.0 2.362 2.073 34.892 3500.0 2.291 2.004 34.885 4000.0 1.351 1.036 34.785 4000.0 1.114 0.806 34.759 4500.0 0.505 0.161 34.694 4388.0 0.303 -0.023 34.680 4862.0 0.278 -0.098 34.676 Station 217 Profil 09 Station 218 Profil 10 35¡ 38.89 W 25¡ 53.88 S 20¡ 00.03 W 23¡ 48.81 S 24.04.1998 UTC 16:45 4215 m 28.04.1998 UTC 10:14 5215 m p dbar T ¡C _ ¡C S p dbar T ¡C _ ¡C S 2.0 25.065 25.065 36.244 4.0 25.685 25.684 36.793 10.0 24.988 24.986 36.273 10.0 25.685 25.683 36.799 20.0 24.951 24.947 36.352 20.0 25.696 25.691 36.806 50.0 24.597 24.586 36.525 50.0 25.701 25.689 36.807 75.0 21.502 21.487 36.470 75.0 23.416 23.400 36.404 100.0 20.511 20.493 36.332 100.0 21.480 21.461 36.303 150.0 18.227 18.201 35.978 150.0 18.158 18.132 35.920 200.0 16.792 16.759 35.747 200.0 15.772 15.741 35.546 250.0 15.415 15.376 35.529 250.0 14.493 14.456 35.349 300.0 14.396 14.351 35.379 300.0 13.376 13.333 35.203 350.0 13.369 13.320 35.269 350.0 12.332 12.285 35.080 400.0 12.432 12.378 35.125 400.0 11.110 11.060 34.937 450.0 11.223 11.166 34.963 450.0 10.240 10.187 34.831 500.0 10.217 10.157 34.834 500.0 9.068 9.013 34.698 600.0 8.166 8.103 34.609 600.0 7.181 7.123 34.519 700.0 6.361 6.297 34.441 700.0 5.495 5.436 34.402 800.0 5.083 5.017 34.364 800.0 4.515 4.452 34.388 900.0 4.157 4.089 34.350 900.0 3.965 3.898 34.410 1000.0 3.811 3.737 34.401 1000.0 3.628 3.555 34.470 1500.0 3.699 3.583 34.727 1500.0 3.129 3.019 34.758 2000.0 3.950 3.783 34.952 2000.0 3.138 2.984 34.916 2500.0 2.950 2.751 34.937 2500.0 2.929 2.730 34.934 3000.0 2.286 2.051 34.892 3000.0 2.700 2.455 34.920 3500.0 1.636 1.366 34.820 3500.0 2.305 2.017 34.883 4000.0 0.794 0.494 34.728 4000.0 1.634 1.310 34.811 4240.0 0.415 0.102 34.689 4500.0 1.227 0.860 34.767 5000.0 0.927 0.512 34.734 5282.0 0.893 0.445 34.726 Station 219 Profil 11 Station 220 Profil 12 16¡ 16.34 W 23¡ 49.59 S 15¡ 00.02 W 23¡ 40.12 S 29.4.1998 UTC 10:07 3874 m 30.04.1998 UTC 02:58 3853 m p dbar T ¡C _ ¡C S p dbar T ¡C _ ¡C S 2.0 25.167 25.167 36.679 4.0 24.989 24.988 36.728 10.0 25.170 25.168 36.722 10.0 24.992 24.990 36.739 20.0 25.175 25.170 36.734 20.0 24.993 24.989 36.757 50.0 25.156 25.145 36.728 50.0 24.989 24.978 36.756 75.0 20.837 20.822 36.219 75.0 21.944 21.929 36.318 100.0 19.614 19.596 36.169 100.0 21.158 21.139 36.302 150.0 18.363 18.337 35.985 150.0 19.166 19.139 36.128 200.0 16.071 16.039 35.610 200.0 17.149 17.116 35.780 250.0 14.656 14.619 35.375 250.0 15.009 14.971 35.427 300.0 13.465 13.423 35.214 300.0 13.424 13.382 35.205 350.0 12.245 12.198 35.072 350.0 12.463 12.416 35.093 400.0 10.778 10.729 34.899 400.0 11.484 11.433 34.976 450.0 9.532 9.481 34.760 450.0 10.188 10.135 34.830 500.0 8.831 8.777 34.685 500.0 8.732 8.677 34.675 600.0 7.020 6.962 34.519 600.0 7.171 7.113 34.541 700.0 5.493 5.433 34.413 700.0 5.778 5.717 34.420 800.0 4.563 4.500 34.386 800.0 4.571 4.508 34.370 900.0 3.938 3.871 34.414 900.0 4.014 3.947 34.393 1000.0 3.527 3.455 34.459 1000.0 3.603 3.530 34.453 1500.0 3.240 3.129 34.806 1500.0 3.088 2.979 34.759 2000.0 3.217 3.061 34.938 2000.0 3.197 3.042 34.933 2500.0 2.888 2.690 34.930 2500.0 2.766 2.571 34.906 3000.0 2.604 2.362 34.907 3000.0 2.654 2.411 34.908 3500.0 2.231 1.945 34.867 3500.0 2.446 2.155 34.887 3900.0 1.937 1.616 34.838 3888.0 2.136 1.811 34.857 Station 221 Profil 13 Station 225 Profil 14 13¡ 59.86 W 24¡ 09.95 S 13¡ 23.07 W 24¡ 10.81 S 30.04.1998 UTC 11:46 3171 m 01.05.1998 UTC 08:17 2741 m p dbar T ¡C _ ¡C S p dbar T ¡C _ ¡C S 4.0 24.725 24.724 36.740 4.0 24.584 24.583 36.668 10.0 24.728 24.725 36.740 10.0 24.594 24.592 36.668 20.0 24.730 24.726 36.739 20.0 24.598 24.593 36.670 50.0 24.723 24.712 36.736 50.0 24.608 24.597 36.670 75.0 22.406 22.391 36.307 75.0 23.072 23.057 36.485 100.0 20.866 20.847 36.233 100.0 20.861 20.842 36.281 150.0 19.339 19.312 36.153 150.0 18.768 18.742 36.061 200.0 16.756 16.724 35.719 200.0 16.094 16.062 35.611 250.0 14.673 14.636 35.377 250.0 14.747 14.709 35.391 300.0 13.215 13.173 35.180 300.0 13.659 13.616 35.240 350.0 11.684 11.638 34.997 350.0 12.359 12.312 35.082 400.0 10.849 10.800 34.899 400.0 11.038 10.988 34.924 450.0 9.994 9.941 34.805 450.0 10.100 10.046 34.819 500.0 8.744 8.690 34.671 500.0 9.021 8.966 34.687 600.0 6.995 6.938 34.506 600.0 7.093 7.035 34.525 700.0 5.632 5.572 34.411 700.0 5.474 5.415 34.415 800.0 4.790 4.726 34.398 800.0 4.709 4.646 34.411 900.0 4.191 4.122 34.424 900.0 4.242 4.173 34.430 1000.0 3.877 3.803 34.471 1000.0 3.909 3.834 34.463 1500.0 3.178 3.067 34.741 1500.0 3.170 3.060 34.741 2000.0 2.864 2.713 34.871 2000.0 2.870 2.720 34.889 2500.0 2.739 2.544 34.897 2500.0 2.761 2.565 34.894 3000.0 2.616 2.374 34.891 2774.0 2.713 2.491 34.895 3200.0 2.608 2.345 34.892 Station 226 Profil 15 Station 229 Profil 16 12¡ 18.11 W 24¡ 10.08 S 11¡ 07.95 W 24¡ 10.25 S 01.05.1998 UTC 15:57 3910 m 02.05.1998 UTC 10:56 3737 m p dbar T ¡C _ ¡C S p dbar T ¡C _ ¡C S 4.0 24.432 24.431 36.637 2.0 24.273 24.273 36.540 10.0 24.432 24.430 36.637 10.0 24.288 24.286 36.538 20.0 24.429 24.425 36.640 20.0 24.293 24.288 36.537 50.0 24.403 24.392 36.644 50.0 24.270 24.260 36.534 75.0 21.050 21.036 36.194 75.0 23.752 23.737 36.372 100.0 19.853 19.834 36.189 100.0 19.784 19.766 35.925 150.0 17.491 17.465 35.810 150.0 16.207 16.183 35.570 200.0 15.543 15.512 35.511 200.0 14.233 14.203 35.299 250.0 14.514 14.476 35.350 250.0 13.320 13.285 35.183 300.0 13.638 13.595 35.231 300.0 12.411 12.371 35.082 350.0 12.554 12.507 35.099 350.0 11.293 11.249 34.952 400.0 11.287 11.236 34.952 400.0 10.116 10.068 34.813 450.0 10.094 10.041 34.815 450.0 9.446 9.395 34.739 500.0 8.905 8.851 34.688 500.0 8.616 8.563 34.652 600.0 7.077 7.019 34.517 600.0 6.754 6.698 34.483 700.0 5.416 5.357 34.407 700.0 5.162 5.105 34.372 800.0 4.728 4.665 34.403 800.0 4.331 4.270 34.403 900.0 4.127 4.058 34.434 900.0 3.893 3.826 34.437 1000.0 3.818 3.744 34.478 1000.0 3.604 3.531 34.475 1500.0 3.144 3.034 34.738 1500.0 3.168 3.058 34.758 2000.0 2.665 2.518 34.832 2000.0 2.661 2.514 34.838 2500.0 2.511 2.321 34.874 2500.0 2.511 2.321 34.874 3000.0 2.478 2.239 34.881 3000.0 2.434 2.195 34.880 3500.0 2.489 2.197 34.880 3500.0 2.400 2.110 34.880 4000.0 2.487 2.139 34.879 3764.0 2.410 2.091 34.881 4006.0 2.487 2.139 34.880 Station 231 Profil 17 Station 232 Profil 18 09¡ 53.92 W 24¡ 09.96 S 09¡ 00.19 W 24¡ 09.91 S 02.05.1998 UTC 23:35 4322 m 03.05.1998 UTC 06:55 4462 m p dbar T ¡C _ ¡C S p dbar T ¡C _ ¡C S 4.0 23.874 23.873 36.566 2.0 23.715 23.715 36.423 10.0 23.873 23.871 36.570 10.0 23.726 23.724 36.424 20.0 23.871 23.867 36.574 20.0 23.735 23.731 36.427 50.0 23.876 23.865 36.573 50.0 23.662 23.652 36.425 75.0 22.069 22.054 36.189 75.0 20.946 20.932 35.978 100.0 19.430 19.412 36.037 100.0 19.052 19.034 35.929 150.0 17.559 17.534 35.791 150.0 17.125 17.100 35.733 200.0 15.069 15.038 35.436 200.0 15.455 15.424 35.488 250.0 13.735 13.699 35.242 250.0 14.211 14.174 35.309 300.0 12.954 12.913 35.145 300.0 12.922 12.881 35.138 350.0 11.884 11.838 35.025 350.0 11.959 11.913 35.031 400.0 11.118 11.068 34.935 400.0 10.862 10.813 34.902 450.0 9.964 9.912 34.801 450.0 9.573 9.522 34.758 500.0 8.367 8.315 34.633 500.0 8.912 8.857 34.676 600.0 6.375 6.320 34.455 600.0 7.260 7.201 34.544 700.0 5.312 5.254 34.391 700.0 5.364 5.306 34.392 800.0 4.365 4.304 34.380 800.0 4.445 4.383 34.373 900.0 3.894 3.827 34.420 900.0 4.127 4.058 34.427 1000.0 3.701 3.628 34.483 1000.0 3.786 3.712 34.474 1500.0 3.332 3.220 34.755 1500.0 3.470 3.356 34.765 2000.0 2.750 2.601 34.848 2000.0 2.737 2.589 34.835 2500.0 2.541 2.350 34.873 2500.0 2.510 2.319 34.873 3000.0 2.429 2.191 34.880 3000.0 2.399 2.161 34.878 3500.0 2.384 2.094 34.880 3500.0 2.361 2.072 34.884 4000.0 2.395 2.050 34.885 4000.0 2.393 2.047 34.887 4374.0 2.428 2.038 34.886 4500.0 2.438 2.033 34.887 4522.0 2.441 2.033 34.887 Station 233 Profil 19 Station 234 Profil 20 08¡ 59.96 W 22¡ 23.96 S 09¡ 00.15 W 21¡ 12.10 S 03.05.1998 UTC 19:00 4192 m 04.05.1998 UTC 03:51 3941 m p dbar T ¡C _ ¡C S p dbar T ¡C _ ¡C S 2.0 24.105 24.105 36.497 4.0 24.325 24.324 36.693 10.0 24.031 24.029 36.552 10.0 24.328 24.326 36.693 20.0 24.018 24.013 36.580 20.0 24.333 24.328 36.693 50.0 24.002 23.992 36.612 50.0 24.336 24.326 36.691 75.0 23.018 23.003 36.397 75.0 21.873 21.858 36.273 100.0 20.287 20.268 36.003 100.0 20.422 20.403 36.141 150.0 17.878 17.853 35.818 150.0 17.202 17.177 35.765 200.0 15.852 15.820 35.536 200.0 15.492 15.461 35.504 250.0 14.185 14.148 35.302 250.0 14.056 14.020 35.286 300.0 12.934 12.893 35.140 300.0 13.295 13.253 35.187 350.0 11.835 11.790 35.018 350.0 11.710 11.665 34.996 400.0 10.389 10.341 34.830 400.0 10.229 10.182 34.829 450.0 9.211 9.161 34.721 450.0 9.126 9.076 34.716 500.0 8.096 8.044 34.603 500.0 8.037 7.986 34.611 600.0 6.102 6.048 34.446 600.0 6.378 6.323 34.501 700.0 4.872 4.816 34.395 700.0 5.088 5.030 34.424 800.0 4.184 4.124 34.414 800.0 4.329 4.268 34.434 900.0 3.867 3.801 34.450 900.0 3.947 3.880 34.468 1000.0 3.646 3.573 34.512 1000.0 3.736 3.663 34.519 1500.0 3.473 3.359 34.810 1500.0 3.439 3.326 34.816 2000.0 3.058 2.905 34.890 2000.0 3.036 2.883 34.898 2500.0 2.589 2.397 34.878 2500.0 2.654 2.461 34.894 3000.0 2.441 2.203 34.878 3000.0 2.441 2.203 34.882 3500.0 2.364 2.075 34.883 3500.0 2.368 2.079 34.881 4000.0 2.382 2.037 34.888 3876.0 2.381 2.050 34.882 4236.0 2.401 2.028 34.889 Station 235 Profil 21 Station 236 Profil 22 09¡ 00.09 W 20¡ 00.03 S 09¡ 46.23 W 18¡ 59.98 S 04.05.1998 UTC 13:03 3959 m 04.05.1998 UTC 21:48 3838 m p dbar T ¡C _ ¡C S p dbar T ¡C _ ¡C S 2.0 23.967 23.967 36.466 4.0 24.448 24.448 36.733 10.0 23.943 23.941 36.461 10.0 24.452 24.450 36.732 20.0 23.890 23.886 36.459 20.0 24.458 24.454 36.733 50.0 23.846 23.836 36.455 50.0 24.412 24.401 36.720 75.0 21.581 21.566 36.252 75.0 21.409 21.394 36.228 100.0 20.324 20.305 36.206 100.0 19.608 19.590 36.066 150.0 18.076 18.050 35.881 150.0 17.286 17.261 35.756 200.0 15.206 15.176 35.431 200.0 14.320 14.291 35.323 250.0 13.364 13.329 35.196 250.0 12.773 12.739 35.124 300.0 11.904 11.865 35.028 300.0 11.544 11.506 34.986 350.0 10.750 10.707 34.906 350.0 10.058 10.017 34.821 400.0 9.552 9.506 34.775 400.0 9.351 9.306 34.753 450.0 8.259 8.212 34.644 450.0 8.538 8.490 34.676 500.0 7.205 7.157 34.552 500.0 7.379 7.330 34.567 600.0 5.883 5.830 34.486 600.0 5.785 5.734 34.484 700.0 5.030 4.973 34.450 700.0 4.723 4.668 34.452 800.0 4.329 4.268 34.458 800.0 4.236 4.175 34.464 900.0 4.001 3.934 34.494 900.0 3.936 3.869 34.499 1000.0 3.840 3.765 34.541 1000.0 3.824 3.750 34.567 1500.0 3.642 3.527 34.824 1500.0 3.668 3.551 34.836 2000.0 3.092 2.938 34.903 2000.0 3.172 3.017 34.904 2500.0 2.643 2.450 34.891 2500.0 2.706 2.512 34.896 3000.0 2.454 2.216 34.884 3000.0 2.466 2.227 34.886 3500.0 2.388 2.099 34.883 3500.0 2.404 2.114 34.883 3962.0 2.396 2.055 34.889 3856.0 2.428 2.098 34.884 Station 236 Profil 23 Station 243 Profil 24 09¡ 46.20 W 18¡ 59.98 S 12¡ 42.67 W 19¡ 22.00 S 05.05.1998 UTC 00:57 3840 m 07.05.1998 UTC 22:22 4536 m p dbar T ¡C _ ¡C S p dbar T ¡C _ ¡C S 2.0 24.431 24.430 36.740 4.0 24.677 24.676 36.697 10.0 24.447 24.445 36.738 10.0 24.673 24.671 36.715 20.0 24.434 24.430 36.738 20.0 24.674 24.670 36.730 50.0 24.434 24.423 36.735 50.0 24.630 24.619 36.739 75.0 22.587 22.572 36.388 75.0 22.372 22.357 36.394 100.0 19.317 19.299 36.047 100.0 20.598 20.579 36.252 150.0 17.077 17.052 35.730 150.0 18.568 18.542 36.046 200.0 14.577 14.547 35.365 200.0 16.025 15.993 35.612 248.0 13.174 13.140 35.178 250.0 14.194 14.158 35.316 300.0 12.601 12.560 35.108 350.0 11.131 11.087 34.959 400.0 9.763 9.717 34.798 450.0 8.568 8.520 34.671 500.0 7.347 7.298 34.567 600.0 5.764 5.712 34.472 700.0 4.829 4.773 34.446 800.0 4.267 4.206 34.457 900.0 3.825 3.759 34.500 1000.0 3.700 3.626 34.548 1498.0 3.482 3.368 34.849 Station 248 Profil 25 17¡ 15.12 W 19¡ 05.75 S 09.05.1998 UTC 18:30 3453 m p dbar T ¡C _ ¡C S 2.0 25.829 25.829 36.947 10.0 25.567 25.564 36.971 20.0 25.541 25.536 36.993 50.0 25.523 25.512 37.005 75.0 23.108 23.093 36.537 100.0 21.152 21.132 36.413 150.0 19.127 19.100 36.152 200.0 16.246 16.214 35.637 250.0 14.339 14.302 35.352 300.0 12.869 12.828 35.167 350.0 11.445 11.401 35.000 400.0 10.030 9.983 34.841 450.0 8.928 8.879 34.728 500.0 7.941 7.890 34.636 600.0 6.127 6.073 34.497 700.0 4.823 4.767 34.431 800.0 4.213 4.153 34.437 900.0 3.847 3.781 34.467 1000.0 3.713 3.640 34.508 1500.0 3.651 3.535 34.847 26 M41 - Bericht, AG Zenk , IfM Kiel Status: 26.08.98