WHP Ref. No.: PR24/PR25/PR22/PR26
Last updated: December 1995

A.	Cruise Narrative

A.1	Highlights

A.1.a	WOCE designation	PR24,PR25,PR22,PR26 
				
A.1.b	EXPOCODE		 76XB09/1

A.1.c	Chief Scientist		Pu Schuzhen
				The First Institute of Oceanography
				State Oceanographic Adminstration
				PO Box 98
				13 Hongao Road
				Qingdao, Shandong Providence
				PRC

A.1.d	Ship			R/V Xiang Yang Hong No. 5
	
A.1.e	Ports of call		 
				 
A.1.f	Cruise dates		16 November 1991 to 11 December 1991

A.2	Cruise Summary Information

A.2.a	Geographic boundaries

A.2.b	Stations occupied

 


A.2.c	Floats and drifters deployed

A.2.d	Moorings deploued or recovered

A.3	List of Principal Investigators
 
 
A.4	Scientific Programme and Methods

To support world Ocean Circulation Experiment (WOCE) program, 
scientists and technicians of State Oceanic Administration from South 
China Sea Branch of SOA (Guangzhou), First Institute of Oceanography 
(Qingdao ), Second Institute of Oceanography (Hangzhou), Third 
Institute of Oceanography (Xiamen), National Marine environment 
Forecasting Centre (Beijing), National Marine Data and Information 
Service (Tianjin), National Centre of Ocean Standard & metrology 
(Tianjin) conducted hydrographic observations aboard R/V Xiang Yang 
Hong No. 5 in the western tropical Pacific Ocean. The objective of 
this component of the WOCE program was to document the water mass 
property distributions of the western tropical Pacific Ocean and 
describe the oceanic velocity field. The cruise summarized here were 
conducted from 16th November 1991 to 11th December 1991. 
Conductivity-Temperature-Depth-Oxygen (CTD/02) data were collected at 
the hydrographic stations to the depths limited by either the CTD 
cable length or echo sounder problems. The cruise reoccupied 
some of the same stations as they were conducted during the 8 cruises 
of the PRC/US TOGA program in a period from December 1985 to July 1990 
in order to provide temporal information. Summarized listings of 
CTD/02 data together with selected physical properties of sea water 
for the cruise are provided here, as well as a description of the 
hardware used and an explanation of the data reduction techniques 
employed.

Introduction

	The WOCE committee of the People's Republic of China (PRC) 
were established in 1990. Director Yan Hongmo of State Oceanic 
Administration (SOA ) of PRC is the chairman of the committee. SOA 
called at some oceanographic scientists to select the area in the 
western tropical Pacific Ocean as the field of investigation for 
Chinese WOCE. It results in the first cruise of the Chinese WOCE, which 
might be considered a component of the international WOCE program.

	The first cruise of the Chinese WOCE took place on 16th 
November 1991 to llth December 1991; A major focus of the cruise has been 
the boundary area of the western tropical Pacific Ocean. In the area 
there are Mindanao Current, Papua New Guinea Coastal Undercurrent, 
Indonesia/Pacific throughflow and the other equatorial currents. The 
results from the cruise are summarized here. The objectives of the 
hydrographic program are to document the thermohaline and water mass 
property distributions in the western Pacific Ocean, to resolve the 
geostrophic transport field of the various currents of the region, and 
to characterize any interannual variations. The cruise track and the 
station positions for the cruise were chosen in an effort to resolve 
the major boundary currents and equatorial currents mentioned above, 
and to provide data for intercomparison with the previous PRC/US TOGA 
cruises. The reoccupation of some of the same stations as they were 
occupied during PRC/US TOGA cruises is important for studying time 
variability and also facilitate calibration of the sensors by 
exploiting the stability of the deep water property. The cruise were 
carried out aboard the R/V Xinag Yang Hong No. 5 operated by SOA. 
Scientific and technical personnel staffing the cruise were a 
combination of the SOA scientific units (Table ). 

Instrumentation

	Two EG&G/Neil Brown Instrument Systems (NBIS) MK IIIb CTDs 
were used as the primary profiling instruments aboard the cruise. The 
instruments (serial numbers 1104 (CTD 11), and 2233 (CTD 13)) sampled 
temperature, conductivity, pressure and dissolved oxygen. A detailed 
description of the instrument can be found in the report by 
Brown and Morrison (1978)- A 12-position General Oceanics rosette 
fitted with 1.7 liter Niskin bottles was used to collect water samples 
for subsequent analysis aboard the vessel. Digital CTD data were acquired 
with a NBIS 1150 deck unit. These raw data were achieved with a 
PC based system (using the EG&G Marine Instruments Oceansoft CTD 
acquisition software) for real time display 
and subsequent data processing.  Water samples from the rosette sampler were 
analyzed for salinity and dissolved oxygen content. Salinity samples 
were analyzed on a Chinese salinometer (serial number 0088091 (SYC2-1A 
type )) supplied by First Institute of Oceanography (Qingdao). 
Dissolved oxygen samples were analyzed using a modified Winkler 
method, all of the titration equipment was supplied by the South 
Branch of SOA (located at Guangzhou), and all of the samplers were 
processed on board.

Data Collection

	Totally sip sections, with stations positioned to optimize the 
resolution of tdransport in the strong current regions near the 
equator and the coasts, were occupied during the cruise. They are the 
18 20 N section from the Phillipine coast to 130 E, the 130 E section 
from 18 20 N to 8 N, the 8 N section from the Phillipine coast to 141.5 E, 
the 141.5 E section from 8 N to the Pupua New Guinea coast, the 
equatorial section from the 141.5 E to 128 E. and the 
Pacific/Indonesia throughflow section from the west end of Papua New 
Guinea to the southeast corner of the Mindanao Island. 
During the cruise, the station depth for CTD casts was limited by 
problems of the board echo sounder. The CTD casting depth was 
determined from the navigating charts if the bottom depth at the 
sta-tions was greater than 1000 m. The CTD was casted to as deep as
the bottom depth was if the station depth was less than 1000 m. Xiang 
yang Hong No. 5 is a vessel with a limited ability to maneuver on the 
wire, thus, strong wind or currents often results in large wire angles 
, limiting casting depths.

The data return for the cruise was excellent, except few 
stations were not completed due to adverse weather conditions effected 
by typhoon.

Data Calibration and Reduction

	Conductivity, temperature and pressure sensors of the CTD 
instruments were calibrated at National Centre of Ocean Standard & 
Metrology (Tianjin) prior to and following the cruise. The detailed 
calibration ability can be found in Millard et al. (1990).

	CTD sensor calibrations applied at sea for data workup and 
instrument quality control were typically the pre-cruise laboratory 
calibrations for conductivity, temperature and pressure. No electronic 
adjustments were made to the sensor interface boards during the 
laboratory calibrations. Instead, temperature, pressure and 
conductivity corrections, determined by polynomial least-square fits 
to the laboratory calibration data were applied to the data, thus the 
performance history of each sensor was maintained. Temperature 
calibrations consisted of a linear or quadratic fit to seven 
temperature points in reference to a platinum thermometer standard. 
Pressure calibrations were done using dead-weight tester at 1000 psi 
intervals for increasing and decreasing pressure. Temperature and 
pressure calibrations were used to scale the data profiles as well as 
the CTD components of rosette sample data files. Conductivity 
calibrations were done in reference to Chinese standard sea water, 
supplied by First Institute of Oceanography (Qingdao). The procedure 
and method of the CTD calibration and data processing are advised on 
with R. C. Millard, WHOI USA. Specific information on actual 
calibrations for each sensor for the cruise can be found in 
Yang(1993). CTD/O2oxygen sensor calibration coefficients were derived 
from comparison to in situ water sample oxygen data within various 
station groupings (Owens and Millard, i985). CTD conductivity sensor 
calibrations for the cruise were determined by considering the 
relationship of precruise laboratory calibrations to in situ rosette 
water sample data (Millard, 1982) and very stable water potential 
temperature/salinity profiles of the western tropical Pacific Ocean.

 A.5	Major Problems and Goals not Achieved


A.6	Other Incidents of Note

A.7	List of Cruise Participants

