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Please cite this data set as:

Lui, C-.T., and S-.C Pai. 2013. Hydrographic and Chemical Data Obtained 
During the R/V Ocean Researcher I Cruise 21OR19910626 in the Pacific Ocean (06/26/1991-07/04/1991). Carbon Dioxide Information
Analysis Center, Oak Ridge National Laboratory, US Department of Energy, Oak Ridge,
Tennessee. doi: 10.3334/CDIAC/OTG.PACIFICA_21OR19910626

Preliminary report
may 15, 1995
A.	Cruise Narrative
A.1	Highlights *Note: This report has information geared to
	Leg 1. 

A.1.a	WOCE Designation	Leg1=PR20/Leg2=PR21
A.1.b	EXPOCODE designation	Leg1=21OR287/1, Leg2=21OR287/2
A.1.c	Chief Scientist		Cho-Teng Liu
				Institute of Oceanography
				National Taiwan University
				Taipei POB 23-13, Taiwan, ROC 10764

A.1.d 	Ship	R/V Ocean Researcher I

A.1.e	Ports of Call	Leg 1: Kaohsiung to San Fernando
                	Leg 2: San Fernando to Kaohsiung

A.1.f	Cruise Dates	Leg 1: June 26-July 4, 1991, southbound
                	Leg 2: July 8-July 12, 1991, northbound

A.2 	Cruise Summary
A.2.a	Geographic boundaries
A.2.b	Total number of stations Occuppied

PR20: 29 CTD stations, including 21 water sample stations
PR21: 13 CTD stations, including 12 water sample stations

A.2.c	Floats and drifters deployed
A.2.d	Moorings deployed or recovered

A.3	 List of Principal Investigators
	Table 1: List of Principal Investigators
Name			Responsibility				Institution*
LIU, Cho-Teng 		calibration, processing and		NTU 
			interpretation of CTD data

PAI, Su-Cheng 		collection, analysis and 		NTU
			interpretation of water
                	sample data

Israel Bentillo 	interpretation of CTD data 		UP
			along with C-T Liu

CHEN, Cheng-Tung Arthur developing method for 			NSYSU
			collecting C-14 samples
*See Table 2 for list of Institution

	Table 2: List of Institutions
Abbreviation			Institution
NTU				National Taiwan University 
				Taipei, Taiwan, ROC 10764

UP				University of the Philippines 
				Quezon City, RP

NSYSU			 	National Sun Yat-sen University 
				Kaohsiung, Taiwan, ROC

A.4. 	Scientific Programme and Methods
This cruise was carried out jointly by oceanographers from the Republic  
of China in Taiwan and from the Republic of the Philippines.  R/V Ocean  
Researcher 1 left Kaohsiung Harbor at 12:00 of June 23, 1991.  Because of the  
severe swell produced by approaching gale system, the ship was not able to  
reach the first CTD station near the southern tip of Taiwan, and she had to  
return Kaohsiung harbor and departured again on June 26.   

A.5.	 Major Problems 

Because the CTD cable has a bend at about 2100 m, many  
of the casts was not able to reach 2000 m depth as planned.

A.6 Other incidents of note 


A.7 List of Cruise Participants     
	Table 3: List of Cruise Participants
Name			Responsibility			Institution*
LIU, Cho-Teng 		chief scientist			NTU	
PAI, Su-Cheng 		chief chemist			NTU
CHIU, Tai-Sheng 	chief zoologist			NTU
CHENG, Shih-Pei 	CTD data processing		NTU
YANG, Chung-Cheng 	nitrate analysis		NTU
JENG, Kwung-Lung 	phosphate, silicate and		NTU 
			nitrite analysis, &          
                	chemical hydrography data
KUO, Ting-Yu 		salinity and dissolved 		NTU
			oxygen analysis
CHEN, Hung-Yu 		heavy metal analysis processing NTU
BENTILLO, Israel G. 	physical oceanographer           UP
WANG, Shu-lun 		pH analysis		      NSYSU
HUANG, Ming-Shung 	Alkalinity		      NSYSU
WANG, Chi-Hua 		pH analysis		      NSYSU
*See Table 2 for list of Institutions

B.	Underway Measurements

B.1	Navigation and bathymetry
B.2	Acoustic Doppler Current Profiler (ADCP)
B.3	Thermosalinograph and underway dissolved oxygen, fluorometer
B.4	XBT and XCTD
B.5	Meteorological observations
B.6	Atmospheric chemistry

C.	Hydrographic Measurements

The pressure, temperature  (T) and salinity (S) were derived from the
CTD data according to the methods described in the SBE-9 CTD manual.
The CTD Digiquartz pressure transducer was calibrated in 1987.  The CTD
temperature sensor was calibrated on 1990/12/05 and 1991/06/14 through
Sea Bird Electronics Inc..  Assuming that the rate of drift of
temperature sensor is constant in time (0.002 C in 6 months), then the
bias of temperature data was about 0.0002 C, which is within the
requirement for WOCE hydrography.  So, no correction is applied on the
temperature data.  The CTD conductivity sensor were calibrated on 23
Feb 1990 and 14 June 1991.  The conductivity and salinity data were
correcty by the following procedure:

1)	Use the Guildline Salinometer to measure the salinity of collected
	water samples.

2)	Use the CTD temperature data (IPTS68) and the measured salinity
	from step (1) to derive the in situ conductivity of each sample.

3)	Use ploynomial fit to derive the bias of CTD's conductivity;
	the bias was found to be negligible.

4)	No correction is applied on either CTD conductivity of salinity

Comparing the T-S data of St 112(20 04 N, 120 42.9 E) along WHP PR21 to
those of St. 36 (19 59.7 N, 123 13.2 E) and St. 37 (22 22.0 N, 121 36.9
E) of INDOPAC Expedition, we found that the T-S curve of St. 112 is
smoother than those of St. 36 and 37 of INDOPAC Expedition.  This
observation agreees with the general case that both the salinity
maximum of NPTW (North Pacific Tropical Water) and the salinity minimum
of NPIW ( North Pacific Intermediate Water) are less apparent for water
on the shelf side of Kuroshio (e.g. at St. 112) than on the deep Ocean side
(e.g. at St. 36 and 37).

The raw CTD data still need further corrections by running parallel
determination of salinity using an inductive bench-type salinometer
(e.g. AUTOSAL).  The accuracy of the AUTOSAL was maintained by
bathc-wise calibration using a certified I.A.P.S.O. standard seawater.
With careful storage of the samples and with extreme precaution sin the
salinity determination, an accuracy of better then 0.001 psu has been
achieved (Fang et al., 1990; Pai et al., 1990).

Dissolved oxygen was determined on board the research vessel using a
modified Winkler titration method (Strickland and Parsons, 1972).  An
ABU80 autotitrator was used to deliver the titrant which provided a
resolution of 0.001 ml and a precision of better than 0.5% for samples
containing 4 ml/l oxygen.  The oxygen sensor installed on the CTD unit
also provided real-time oxygen profiles, but its reliability does not
justify reporting it.

Nitrite was determined manually on-board the ship within 3 hours after
collection of the water samples.  A modified pink azo dye method (Pai
et al., 1990) was used where in 40-ml aliquot of the sample was treated
with 1 ml of 2% s/v sulphanilamide prepared in 15% HCL, followed by 1
ml of 0.3% w/v of N-1- naphthylenediamine solution.  The solution was
then measured at 543 nm using 5 cm long cuvettes.  The accuracy was
monitored by running known reference standards to obtain a molar
extinction coefficient of 52000 +/- 500/cm/M.  A precision of ca. 2%
was obtained for samples containing 1 uM nitrite.

Reactive phosphate was also determined immediately after sample
collection as significant variations of the concentrations could
otherwise occur (Reily, 1975).  The reagents for phosphate were
prepared according to the method suggested by Murphy and Riley (1962).
The molar extinction coefficient for the phospho-antimonyl-molybedenum
blue complex formed was found to be 22400 +/- 200/cm/M (Pai et al.,
1990) and running standards with each batch of samples analyzed ensured
that both the accuracy and precision of the determination were
maintained at ca. 1%.

Nitrate was determined on-board with a home-makde flow injection
analyzer.  The system consisted of a reduction coil threaded with a 1-m
long copper-coated cadmium wire.  The sample was loaded through a
six-way injection valve, and nitrate in the sample was reduced on-line
to nitrite.  The appropriate reagents were then added and the resulting
colored solution measured with as pectrophotometer. Details of the
automated system has been presented elsewhere (Pai et al., 1990).  A
precision of ca. 1% was archived for samples containing 10 uM nitrate.
Calibration curves were constructed by spiking known amouts of the
certified Merck standard to a freshly filtered surface seawater.

The determination of silicate was carreid out within several hours of
sample collection using a home-made flow injection analyzer.  The
reagents used were similar to that suggested by Strickland and Parsons
(1972) except for ascorbic acid which was used as a reductant to
replace the metol-sulphite solution.  The determination was carried
manually and calibration curves were constructed by using appropriate
concentrations of Si standard (Titrosol, Merck).

D.	Acknowledgments

E.	References

Unesco, 1983. International Oceanographic tables. Unesco Technical Papers in 
Marine Science, No. 44.

Unesco, 1991. Processing of Oceanographic Station Data, 1991. By JPOTS
editorial panel.

F.	WHPO Summary

Several data files are associated with this report.  They are the OR287l1.sum, 
OR287l1.hyd, OR287l1.csl and *.wct files.  The OR287l1.sum file contains a 
summary of the location, time, type of parameters sampled, and other pertient
information regarding each hydrographic station.  The OR287l1.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 The OR287l1.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 OR287l1.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 coriolius parameter, N is the bouyancy
frequency (data expressed as radius/sec), and g is the local
acceleration of gravity. 

Bouyancy 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, Processing of 
Oceanographic station data.

Neutral Density (GAMMA-N: KG/M3) is calculated with the program GAMMA-N
(Jackett and McDougall) version 1.3 Nov. 94.