A.	Cruise Narrative

A.1	Highlights

A.1.a	WOCE designation	P18S
				P18N


A.1.b	EXPOCODE		P18S: 31DSCG94/2
				P18N: 31DSCG94/3

A.1.c	P18S:

	Chief Scientist		Bruce Taft
				NOAA/PMEL
				NOAA Building 3
				Bin C15700
				7600 Sand Point Way NE
				Seattle  WA   98115-0070
				Phone: 206-526-4146
				Fax: 206-526-6744
				Internet: taft@noaapmel.gov

	Co-Chief Scientist	John Bullister
				NOAA/PMEL
				NOAA Building 3
				Bin C15700
				7600 Sand Point Way NE
				Seattle  WA   98115-0070
				Phone: 206-526-6741
				Fax: 206-526-6744
				Internet:  bullister@noaapmel.gov

	P18N

	Chief Scientist		Gregory Johnson
				NOAA/PMEL
				NOAA Building 3
				7600 Sand Point Way NE
				Seattle  WA   98115-0070
				Phone: 206-526-6806
				Fax: 206-526-6744
				Internet:gjohnson@noaapmel.gov

	Co-Chief Scientist	Richard Feely
				NOAA/PMEL
				NOAA Building 3
				7600 Sand Point Way NE
				Seattle  WA   98115-0070

A.1.d	Ship			R/V Discoverer

A.1.e	Ports of Call		P18S: Punta Arenas to Easter Island
				P18N: Easter Island to San Diego

A.1.f	Cruise dates		P18S: Feb 22 - March 2 1994
				P18N: March 27 - April 3 1994

A.2	Cruise Summary Information

A.2.a	Geographic boundaries

             23 N
      110 W        103 W
             67 S

A.2.b	Stations Occupied

A total of 185 full water column CTD/water sample stations were made along the
section from 67 S 103 W to 23 N 110 W.  Of these, 158 stations were
made using a 36-position, 10-liter bottle frame with a lowered Acoustic
Doppler Current Profiler (ADCP) and a transmissometer.  The other 27
stations were made using a 24-position, four-liter bottle frame
deployed primarily during heavy weather.  A Sea-Bird Electronics 911plus CTD
was mounted in each frame. In addition to a set of temperature and
conductivity sensors resident on each CTD, a single set of mobile temperature,
conductivity, and dissolved oxygen sensors was used at every station for
quality control.

	Water samples were collected at every station for analyses of salt,
dissolved oxygen and dissolved nutrients (i.e., silicate, nitrate, nitrite
and phosphate). Samples were drawn at selected locations for analysis of
CFC-11, CFC-12, dissolved inorganic carbon (DIC), total alkalinity, pH, pCO2,
3He, tritium, dissolved organic carbon, carbon isotopes, oxygen isotopes,
and other variables. Daily shallow casts were made for assessment of various biological
parameters, including productivity. A total of 25 ALACE (Autonomous Lagrangian
Circulation Explorer) floats were deployed during the cruise. Nineteen
XCTDs were successfully launched between CTD/O2 stations from 1 - 9.5 N.
Underway measurements included ADCP data, meteorological variables, bottom
depth, pH, pCO2, atmospheric CFCs, nitrate, and chlorophyll.

A.2.c	Floats and drifters deployed

ALACE Floats were launched at 25 locations listed in Table 1. Twelve
ALACE floats were released on Leg 2 and thirteen on Leg 3.

Table 1: Time and location of ALACE float deployments

Date		Time		Latitude	Longitude
-----------------------------------------------------------------
022494 		0756    	55 50.17 S 	 80 22.34 W
022494 		1636    	56 39.64 S  	 81 46.87 W
022494 		2130    	57 30.02 S  	 83 17.12 W
022594 		0228    	58 19.87 S  	 84 45.79 W
022594 		0725    	59 09.26 S  	 86 18.96 W
022594 		1210    	59 59.90 S  	 87 51.50 W
030894 		1025    	55 10.40 S 	103 01.09 W
031094 		2028    	49 49.28 S 	103 00.10 W
031394 		0637    	44 58.99 S 	103 00.25 W
031594 		0117    	40 00.99 S 	103 00.55 W
031894 		1200    	35 00.40 S 	103 00.74 W
032094 		0739    	30 00.15 S 	103 01.53 W
032994 		1341    	25 00.24 S	103 00.05 W
033194 		2011    	20 29.51 S 	102 59.98 W
040494 		0005    	14 59.70 S 	103 00.01 W
040694 		1917     	9 59.76 S 	103 00.70 W
040994 		1441     	6 09.09 S 	108 38.61 W
041094 		2307     	3 59.28 S 	110 19.78 W
041294 		1838     	1 20.27 S 	110 19.94 W
041494 		1443     	1 00.38 N 	110 19.96 W
041694 		1431     	3 59.69 N 	110 19.93 W
041794 		1731     	5 59.90 N 	110 20.30 W
041994 		1956    	10 00.78 S 	110 00.19 W
042194 		1819    	14 29.77 S 	110 00.03 W
042394 		2246    	18 59.93 S 	109 59.80 W
------------------------------------------------------------------


A.2.d	Moorings deployed or recovered

A.3	Principal Investigators

Table 2: List of Principal Investigators

Measurement		   Principal Investigator	Institution
---------------------------------------------------------------------
CTD/O2			      B. Taft, G. Johnson	PMEL
Chlorofluorocarbons (CFCs)    J. Bullister		PMEL
C-14 (AMS radiocarbon), C-13  P. Quay			UW
Nutrients		      K. Krogsland  		UW
Dissolved Oxygen              J. Bullister		PMEL
Helium/tritium 		      W. Jenkins		WHOI
CO2 (alkalinity)	      F. Millero		UM
Total CO2 (coulometry), pCO2  R. Feely			PMEL
pH			      R. Byrne			USF
ADCP			      P. Hacker			UH
ALACE floats		      R. Davis			SIO
Underway stmospheric/surface
  halocarbons, nitrous oxide  J. Butler			CMDL
Productivity		      F. Chavez			MBARI
---------------------------------------------------------------------
NOAA/PMEL		National Oceanic and Atmospheric Adminstration
			Pacific Marine Environmental Laboratory
USF			University of South Florida
MBARI			Monterey Bay Aquarium Research Institute
SIO			Scripps Institution of Oceanography
UM			University of Miami
UW			University of Washington
UH			University of Hawaii
WHOI			Woods Hole Oceanographic Institution
CMDL			NOAA Climate Modelling and Diagnostics Laboratory
---------------------------------------------------------------------

A.4 	Scientific Programme and Methods


     The long term objective of the Climate and Global Change Program is to
provide reliable predictions of climate change and associated regional
implications on time scales ranging from seasons to a century or more.  In
support of NOAA's Climate Program, PMEL scientists have been measuring the
growing burden of greenhouse gases in the Pacific Ocean and the overlying
atmosphere since 1980.  The NOAA Office of Global Programs (OGP) sponsored
Ocean Tracers and Hydrography Program and Ocean-Atmosphere Carbon Exchange
Study (OACES) studies ocean circulation, mixing processes, and the rate at
which CO2 and chlorofluorocarbons (CFCs) are taken up and released by the
oceans.  Work on this cruise was cooperative with the World Ocean Circulation
Experiment (WOCE) and the U.S. Joint Global Ocean Flux Study (JGOFS).  The
research was designed to (1) describe water properties and relate them to
circulation processes throughout the water column in the eastern Pacific Ocean;
(2) determine the sources and sinks of carbon dioxide along 103-110W; (3) study
the invasion of CFCs in the ocean; and (4) provide a high quality set of
baseline measurements for the continuing evaluation of changes in ocean content
of dissolved gasses, water properties, and circulation.  This section fills a
gap in the eastern Pacific between WOCE Hydrographic Programme (WHP) meridional
sections P19 (along 90W) and P17 (along 135W).  The southern end of this
section intersects WHP S4, an E-W section along 67S occupied in 1992.

     During the transit (leg 1) from Seattle, Washington to Punta Arenas, Chile,
a test station was occupied in the Puget Sound to evaluate the CTD/rosette
system.  This profile was not processed and is not included in this data
report.  In response to significant volcanic activity detected by the VENTS
monitoring system at the East Blanco Depression (44 12N, 129 42W), 6 stations
were occupied in this area during leg 1.  The NOAA/PMEL VENTS program focuses
research on determining the oceanic impacts and consequences of submarine
hydrothermal venting.  This event was particularly interesting as the area is
a pull-apart basin in a transform zone, possibly the site of early ridge
formation.

     Occupation of WOCE section P18 began with station 10 of leg 2, after two
test casts were completed enroute to 67S, 103W from Punta Arenas, Chile.
Seventy-eight full water column hydrographic stations were occupied east of the
Pacific Rise along 103W from 67S to 27S.  Stations were spaced at 30 nm
intervals except from 58 30S to 48S where spacing was increased to 40 nm
intervals to make up time lost from bad weather and winch level wind problems.
Features sampled during leg 2 included the Polar and Subantarctic Fronts of the
Antarctic Circumpolar Current, the Subtropical Front, the Subantarctic Mode
Water, the Antarctic Intermediate Water, the Circumpolar Deep Water spreading
to the northern reaches of the Southeast Pacific Basin, and currents along the
Sala y Gomez Fracture Zone.

     During leg 3 stations continued northward along 103W to 10S at 30 nm
intervals.  The section turned northwestward from 10S to 5S with 40 nm station
spacing to cross the East Pacific Rise in a perpendicular fashion.  The 30 nm
spacing was resumed from 5S to 3S northward along 110 20W.  From 3S to 3N
stations were occupied every 20 nm along the same longitude.  From 3N to 22 30N
stations were occupied at 30 nm intervals, except from 12N to 16N, where the
spacing was again increased to 40 nm to make up for time lost to winch level
wind problems.  A gradual shift in the longitude from 110 20W to 110W was made
between 8N and 10N.  North of 22 30N station spacing was reduced to as little
as 3 nm over the rapidly shoaling bathymetry approaching Cabo San Lucas.  The
line was completed in 200 m of water at 22 51N, 110W.  During leg 3, 107 full
water column hydrographic stations were occupied sampling the deep waters of
the Bauer Basin, currents associated with the flanks of the East Pacific Rise,
tropical water masses and currents over the full water column, the northern
mid-depth helium-3 plume, and the oxygen depleted layer of the tropical Eastern
Pacific.

     Full water column CTD/O2 profiles were collected at all stations.  Lowered
Acoustic Doppler Current Profiler (ADCP) measurements were also collected on
most casts.  In addition, underway salinity, temperature, and CO2 measurements
were taken along the cruise track.  Shallow productivity casts were made daily,
ALACE floats were launched at predetermined locations, and XCTDs were
successfully dropped in a high-resolution survey from 1N to 9.5N.  Water samples
were analyzed for a suite of anthropogenic and natural tracers including
salinity, dissolved oxygen, inorganic nutrients, CFCs, pCO2, total CO2, pH,
total alkalinity, helium, tritium, C-13, C-14, O-18, dissolved organic carbon,
and dissolved organic nitrogen.  Samples were collected from productivity casts
for chlorophyll and primary productivity.

Leg 1 (Seattle, Washington to Punta Arenas, Chile)

This leg was a transit leg with a test station occupied in the Puget Sound to evaluate the CTD/rosette
system.  This profile was not processed and is not included in this data
report.  In response to significant volcanic activity detected by the VENTS
monitoring system at the East Blanco Depression (44 12N, 129 42W), 6 stations
were occupied in this area during leg 1.

Leg 2 (Punta Arenas - Easter Island).

This leg consisted of 78 stations along 103 W; the first station on the
WOCE Line P18 (#10) was occupied at 67 00 S 103 00 W on 26 February
1994 and the final station at 26 00 S 103 00 W on 23 March 1994.
Except for  10 degrees of latitude span (58 30 S - 48 30 S), the
station spacing was 30 miles.  The station spacing was increased to 40
miles in the above mentioned latitudinal band because of time lost to
heavy weather and slower than normal retreival rates of the CTD
package due to problems with the winch level wind.  All CTD stations
were full depth (nominally 10 m above the bottom).  Two CTD/rosette
packages were used: a 24 position 4 l bottle rosette (21 stations) and
a 36 position 10 l bottle rosette (57 stations).  The choice between
the two systems was usually dictated by the severity of the weather.
On stations where the large rosette was used, a LADCP was attached to
the rosette frame which reduced the number of bottle positions from 36
to 33.  Shallow (200 m) productivity bottle casts with light
transmission profiles were made at 23 stations.  Twelve ALACE floats
were released at predetermined locations along the section and on the
transit to the first station.

Leg 3 (Easter Island - San Diego).

A similar observational program was carried out on this leg (107
stations) with the following changes from the nominal 30-mile station
spacing.  Stations were occupied at 40 mile intervals along a dog-leg
section across the East Pacific Rise from 10 S 103 W to 5 S 110 20 W.
Thirty-mile spacing was resumed between 5 S and 3 S and then reduced
to 20 miles between 3 S and 3 N.  From 3 N to 22 30 N stations were
occupied at 30 mile intervals except between 12 N and 16 N, where
spacing was again relaxed to 40 miles. Between 8 N and 10 N a gradual
shift in longitude from 110 20 W to 110 00 W was made.  As the ship
approached Cabo San Lucas, at the end of the section, spacing was
reduced to as little as 3 miles over the steeply shoaling bathymetry.
Only on six stations, during reterminations of the CTD cable,  was the
24 bottle rosette used.

Discussion:

The basic goals of the cruise were accomplished.  All casts were made
to the bottom.  Station spacing only occasionally was increased to 40
miles from the nominal WOCE interval of 30 miles.  There were no
significant gaps in sampling any of the variables.  Preliminary
analysis of the Seabird CTD measurements and bottle data indicate that
they will meet the WOCE standards.


A.5	Major Problems and Goals not Achieved

A.6	Other Incidents of Note

A.7	List of Cruise Participants

A list of cruise participants is found in Table 3.

TABLE 3:  Cruise Participants
---------------------------------------------------------------------
Institutions:
     NOAA Pacific Marine Environmental Laboratory (PMEL)
     NOAA Atlantic Oceanographic and Meterological Laboratory (AOML)
     NOAA Climate Modelling and Diagnostics Laboratory (CMDL)
     Monterey Bay Aquarium Research Institute (MBARI)
     Scripps Institution of Oceanography (SIO)
     University of Hawaii (UH)
     University of Washington (UW)
     University of Miami (UM)
     University of South Florida (USF)
     Woods Hole Oceanographic Institution (WHOI)

---------------------------------------------------------------------

     Name		    Responsibility	Leg 1	Leg 2	Leg 3

     Andrew Dickson, SIO     Chief Scientist      x
     Bruce Taft, PMEL        Chief Scientist		  x
     John Bullister, PMEL    Co-Chief Scientist           x
     Gregory Johnson, PMEL   Chief Scientist      x               x
     Richard Feely, PMEL     Co-Chief Scientist                   x
     Kristene McTaggart, PMEL   CTD               x       x       x
     Nordeen Larson, Sea-Bird   CTD               x       x
     Gregg Thomas, AOML         salinity                  x       x
     David Wisegarver, PMEL	CFC		  	  x	  x
     C.J. Beegle, UW            CFC                       x
     Kirk Hargreaves, PMEL	oxygen/CFC                x	  x
     David Jones, PMEL          oxygen  			  x
     Katherine Krogslund, UW    nutrients    		  x       x
     Calvin Mordy, PMEL         nutrients                 x       x
     Kerry Jones, PMEL          TCO2              x       x       x
     Thomas Lantry, AOML        TCO2                      x       x
     Marilyn Roberts, PMEL      TCO2                              x
     Dana Greeley, PMEL         pCO2                      x       x
     Catherine Cosca, PMEL      pCO2                      x
     Matthew Steckley, AOML     pCO2                              x
     Sonya Olivella, UM		alkalinity                x
     J. Zhang, UM               alkalinity                x
     Bernardo Vargas, UM	alkalinity                x
     Essa Peltola, UM	 	alkalinity			  x
     Michael De Alessi, UM	alkalinity			  x
     Mary Roche, UM		alkalinity			  x
     Robert Byrne, USF          pH                        x
     Renate Bernstein, USF      pH 			  x
     Huining Zhang, USF         pH			  x       x
     Sean McElligott, USF	pH				  x
     Frederick Stengard, USF    pH				  x
     Craig Huhta, UH		ADCP			  x
     Claude Lumpkin, UH         ADCP                              x
     Joshua Curtice, WHOI       helium, tritium           x
     Scott Birdwhistell, WHOI   helium, tritium			  x
     Dennis Hansell, BBSR	DOC			  x
     Rhonda Kelly, BBSR         DOC                               x
     James Green, UW            C-13, C-14                x
     Elizabeth Houzel, UW       C-13, C-14                        x
     Kurt Buck, MBARI           productivity              x       x
     Thomas Hayden, USC         productivity              x
     Gregory Morris, USC        productivity              x
     Raphael Kudela, MBARI      productivity			  x
     Dante Gutierrez-Besa, SHOA Chilean Observer          x
     Diego Lopez-Veneroni, Texas A&M
				Mexican Observer                  x
     Humberto Perez-Ortiz, Direccion General de Oceanografia Naval,
       Secretaria de Marina     Mexican Observer		  x
---------------------------------------------------------------------


B.1	Navigation and bathymetry

SeaBeam multibeam sonar was used continuously for bathymetry during
both legs. Navigation was by means of the Global Positioning System
(GPS).

B.2	Acoustic Doppler Current Profiler (ADCP)

Shipboard ADCP measurements, along with global position system (GPS)
data, were collected continuously along the track to measure the
velocity profile in the upper 500 m.

B.3	Thermosalinograph and underway dissolved oxygen, etc

A thermosalinograph was operated continuously on both legs.

pCO2 and pH were measured while underway together with
photosynthetically active radiation, nitrate and chlorophyll
concentrations.


B.4	XBT and XCTD

Nineteen XCTDs were dropped along 110 20 W between 1 10 N  and 9 45 N at
locations halfway between successive CTD stations on Leg 3. Times and
positions of each deployment are shown in Table 4.

TABLE 4:  Deployment times and locations for XCTD casts

Date		Time	Latitude	Longitude
--------------------------------------------------------
012994 		0355	44 12.97 N 	129 37.08 W
030294 		1916	62 27.85 S 	102 58.45 W
030394 		0941	61 25.90 S 	102 58.90 W
031094 		0556	51 09.50 S 	103 00.60 W
041494 		1540	 1 10.01 N 	110 19.87 W
041494 		2208	 1 30.10 N 	110 19.60 W
041594 		0340	 1 50.30 N 	110 19.70 W
041594 		0933	 2 10.10 N 	110 20.00 W
041594 		1455	 2 30.00 N 	110 19.80 W
041594		2116	 2 50.00 N 	110 19.90 W
041694 		0250	 3 15.00 N  	110 19.90 W
041694 		0942	 3 45.00 N 	110 19.40 W
041694 		1546	 4 15.00 N 	110 19.80 W
041694 		2313	 4 45.00 N 	110 20.00 W
041794 		0536	 5 16.28 N 	110 19.77 W
041794 		1227	 5 45.00 N 	110 20.00 W
041794 		1845	 6 15.03 N 	110 20.46 W
041894 		0038	 6 45.00 N 	110 20.60 W
041894 		0659	 7 15.00 N 	110 20.61 W
041894 		1307	 7 45.00 N 	110 19.90 W
041894 		2011	 8 15.00 N 	110 17.74 W
041894 		0159	 8 45.10 N 	110 12.50 W
041994 		0822	 9 15.00 N 	110 07.60 W
--------------------------------------------------------


B.5	Meteorological observations


B.6	Atmospheric chemistry

3/8" O.D. Dekaron air sampling lines (reinforced plastic tubing) was
run from the CFC van to the bow and stern and air was analyzed
continuously for: CFC-11 CFC-12 CFC-113 Carbon tetrachloride Methyl
chloroform

C.	Hydrographic Measurements

C.1. CTD/O2 Measurements and Calibrations
		(K.E. McTaggart, G.C. Johnson, and B.A. Taft)

C.1.1.  STANDARDS AND PRE-CRUISE CALIBRATIONS

     The CTD system is a real time data system with the CTD data from a
Sea-Bird Electronics, Inc. (SBE) 9plus underwater unit transmitted via a
conducting cable to the SBE 11plus deck unit.  The serial data from the
underwater unit is sent to the deck unit in RS-232 NRZ format using a 34560 Hz
carrier-modulated differential-phase-shift-keying (DPSK) telemetry link.  The
deck unit decodes the serial data and sends it to a personal computer for
display and storage in a disk file using Sea-Bird SEASOFT software.

     The SBE 911plus system transmits data from primary and auxiliary sensors
in the form of binary number equivalents of the frequency or voltage outputs
from those sensors.  The calculations required to convert from raw data to
engineering units of the parameters being measured are performed by software,
either in real-time, or after the data has been stored in a disk file.

     The SBE 911plus system is electrically and mechanically compatible with
standard, unmodified rosette water samplers made by General Oceanics (GO),
including the 1016 36-position sampler.  An optional modem and rosette
interface allows the 911plus system to control the operation of the rosette
directly, and without interrupting the data from the CTD, eliminating the need
for a rosette deck unit.

     The SBE 9plus underwater unit uses Sea-Bird's standard modular temperature
(SBE 3) and conductivity (SBE 4) sensors which are mounted with a single clamp
and "L" bracket to the lower end cap.  The conductivity cell entrance is
co-planar with the tip of the temperature sensor's protective steel sheath.
The pressure sensor is mounted inside the underwater unit main housing and is
ported to outside pressure through the oil-filled plastic capillary tube seen
protruding from the main housing bottom end cap.  A compact, modular unit
consisting of a centrifugal pump head and a brushless DC ball bearing motor
contained in an aluminum underwater housing pump flushes water through sensor
tubing at a constant rate independent of the CTD's motion.  This improves
dynamic performance.  Motor speed and pumping rate (3000 rpm) remain nearly
constant over the entire input voltage range of 12-18 volts DC.

     The SBE 11plus deck unit is a rack-mountable interface which supplies DC
power to the underwater unit, decodes the serial data stream, formats the data
under microprocessor control, and passes the data to a companion computer.  It
provides access to the modem channel and control of the rosette interface.
Output data is in RS-232 (serial) format.

C.1.1.a.  Conductivity

     The flow-through conductivity sensing element is a glass tube (cell) with
three platinum electrodes.  The resistance measured between the center
electrode and end electrode pair is determined by the cell geometry and the
specific conductance of the fluid within the cell, and controls the output
frequency of a Wien Bridge circuit.  The sensor has a frequency output of
approximately 3 to 12 kHz corresponding to conductivity from 0 to 7 S/m (0 to
70 mmho/cm).  The SBE 4 has a typical accuracy/stability of +/- 0.0003
S/m/month; resolution of 0.00004 S/m at 24 samples per second; and 6800 meter
anodized aluminum housing depth rating.

     Pre-cruise sensor calibrations were performed at Sea-Bird Electronics,
Inc. in Bellevue, Washington.  The following coefficients were entered into
SEASOFT using software module SEASON:

	S/N 1177  September 22, 1993	   S/N 1247  January 21, 1994

	    a =  2.28847772e-05                a =  1.76162580e-05
	    b =  5.58250114e-01		       b =  5.50791410e-01
	    c = -4.14341657e+00                c = -4.07804361e+00
	    d = -9.59251789e-05                d = -9.32262258e-06
	    m =  4.1                           m =  4.2

Conductivity calibration certificates show an equation containing the
appropriate pressure-dependent correction term to account for the effect of
hydrostatic loading (pressure) on the conductivity cell:

	C (S/m) = (af^m + bf^2 + c + dt) / [10 (1 - 9.57e-8 p)]

where a, b, c, d, and m are the calibration coefficients above, f is the
instrument frequency (kHz), t is the water temperature (C), and p is the water
pressure (decibars).  SEASOFT automatically implements this equation.

C.1.1.b.  Temperature

     The temperature sensing element is a glass-coated thermistor bead,
pressure-protected by a stainless steel tube.  The sensor output frequency
ranges from approximately 5 to 13 kHz corresponding to temperature from -5 to
35 degrees Celsius.  The output frequency is inversly proportional to the
square root of the thermistor resistance which controls the output of a
patented Wien Bridge circuit.  The thermistor resistance is exponentially
related to temperature.  The SBE 3 thermometer has a typical accuracy/stability
of +/- 0.004 C per year; and resolution of 0.0003 C at 24 samples per second.
The SBE 3 thermometer has a fast response time of 70 milliseconds.  It's
anodized aluminum housing provides a depth rating of 6800 meters.

     Pre-cruise sensor calibrations were performed at Sea-Bird Electronics,
Inc. in Bellevue, Washington.  The following coefficients were entered into
SEASOFT using software module SEASON:

	S/N 1455  January 13, 1994	   S/N 1461  February 11, 1994

	   a  = 3.68103063e-03                a  = 3.68110418e-03
	   b  = 6.03073078e-04		      b  = 6.00486851e-04
	   c  = 1.51707342e-05                c  = 1.48701147e-05
	   d  = 2.20648879e-06                d  = 1.99797919e-06
	   f0 = 6228.23                       f0 = 6212.56

Temperature (IPTS-68) is computed according to

        T (deg C) = 1/{a+b[ln(f0/f)]+c[ln^2(f0/f)]+d[ln^3(f0/f)]}-273.15

where a, b, c, d, and f0 are the calibration coefficients above and f is the
instrument frequency (kHz).  SEASOFT automatically implements this equation.

C.1.1.c.  Pressure

     The Paroscientific series 4000 Digiquartz high pressure transducer uses a
quartz crystal resonator whose frequency of oscillation varies with pressure
induced stress measuring changes in pressure as small as 0.01 parts per million
with an absolute range of 0 to 10,000 psia (0 to 6885 decibars).  Also, a
quartz crystal temperature signal is used to compensate for a wide range of
temperature changes.  Repeatability, hysteresis, and pressure conformance are
0.005% FS.  The nominal pressure frequency (0 to full scale) is 34 to 38 kHz.
The nominal temperature frequency is 172 kHz + 50 ppm/degree Celsius.

     Pre-cruise sensor calibrations were performed at Sea-Bird Electronics,
Inc. in Bellevue, Washington.  The following coefficients were entered into
SEASOFT using software module SEASON:

	S/N 53960  August 4, 1993	   S/N 53586  October 29, 1993

	    c1 = -43150.48                     c1 = -39204.51
	    c2 =  4.54280e-01                  c2 =  6.23456e-01
	    c3 =  1.34438e-02                  c3 =  1.35057e-02
	    d1 =  0.037952                     d1 =  0.038943
	    d2 =  0.0                          d2 =  0.0
	    t1 =  30.34230                     t1 =  30.46303
	    t2 = -1.80938e-04                  t2 = -9.018862e-05
	    t3 =  4.61615e-06                  t3 =  4.52889e-06
	    t4 =  2.08422e-09                  t4 =  3.30959e-09
	    t5 =  0.0                          t5 =  0.0

Pressure coefficients are first formulated into

		c  = c1 + c2*U + c3*U^2
		d  = d1 + d2*U
		t0 = t1 + t2*U + t3*U^2 + t4*U^3 + t5*U^4

where U is temperature in degrees Celsius.  Then pressure is computed according
to

	P (psia) = c * [1 - (t0^2/t^2)] * {1 - d[1 - (t0^2/t^2)]}

where t is pressure period (microsec).  SEASOFT automatically implements this
equation.

C.1.1.d.  Oxygen

     The SBE 13 dissolved oxygen sensor uses a Beckman polarographic element to
provide in-situ measurements at depths up to 6800 meters.  This auxiliary
sensor is also included in the path of pumped sea water.  Oxygen sensors
determine the dissolved oxygen concentration by counting the number of oxygen
molecules per second (flux) that diffuse through a membrane.  By knowing the
flux of oxygen and the geometry of the diffusion path the concentration of
oxygen can be computed.  The permeability of the membrane to oxygen is a
function of temperature and ambient pressure.  The interface electronics
outputs voltages proportional to membrane current (oxygen current) and membrane
temperature (oxygen temperature).  Oxygen temperature is used for internal
temperature compensation.  Computation of dissolved oxygen in engineering units
is done in the software.  The range for dissolved oxygen is 0 to 15 ml/l;
accuracy is 0.1 ml/l; resolution is 0.01 ml/l.  Response times are 2 seconds at
25 degrees Celsius and 5 seconds at 0 degrees Celsius.

The following oxygen calibrations were entered into SEASOFT using SEACON:

	S/N 130309  September 7, 1993

	      m =  2.4544 e-7
	      b = -4.6633 e-10
	      k =  8.9224
	      c = -6.9788

The use of these constants in linear equations of the form I = mV + b and
T = kV + c will yield sensor membrane current and temperature (with a maximum
error of about 0.5 degrees Celsius) as a function of sensor output voltage.
These scaled values of oxygen current and oxygen temperature were carried
through the SEASOFT processing stream unaltered.


C.1.2.  DATA ACQUISITION

     CTD measurements were made using one of two Seabird 9plus CTDs each
equipped with a fixed pumped temperature-conductivity (TC) sensor pair.  A
mobile pumped TC pair with dissolved oxygen sensor was mounted on whichever CTD
was in use so that dual TC measurements and dissolved oxygen measurements were
always collected.  The TC pairs were monitored for calibration drift and shifts
by examining the differences between the two pairs on each CTD and comparing
CTD salinities with bottle salinity measurements.

     PMEL's Sea-Bird 9plus CTD/O2 S/N 09P8431-0315 (sampling rate 24 Hz) was
mounted in a 36-position frame and employed as the primary package.  Auxiliary
sensors included a lowered ADCP, Metrox load cell, Benthos altimeter, and
SeaTech transmissometer.  Water samples were collected using a General Oceanics
36-bottle rosette and 10-liter Nisken bottles.  The primary package was used
for the majority of 194 casts.

     PMEL's Sea-Bird 9plus CTD/O2 S/N 329053-0209 (sampling rate 24 Hz) was
mounted in a 24-position frame and employed as the backup package.  Auxiliary
sensors included a Metrox load cell and Benthos altimeter.  Water samples were
collected using a Sea-Bird 24-bottle rosette, and 4-liter Niskin bottles.
There were 29 bad weather stations made using the smaller backup package.

     The package entered the water from the stern of the ship and was held
5-20 m beneath the surface for one minute in order to activate the pump and
attach tag lines for package recovery.  Under ideal conditions the package was
lowered at a rate of 30 m/min to 50 m, 45 m/min to 200 m, and 60 m/min to depth.
Ship roll often caused substantial variation about these mean lowering rates,
especially at southern ocean stations.  Load cell values were monitored in
real-time during each cast.  The position of the package relative to the bottom
was monitored on the ship's Precision Depth Recorder (PDR).  A bottom depth was
estimated from bathymetric charts and the PDR ran during the bottom 1000 m of
the cast.  Fig. 2 shows the depths of bottle closures during the upcast.

     Upon completion of the cast, sensors were flushed with deionized water and
stored with a dilute Triton-X solution in the plumbing.  Niskin bottles were
sampled for salinity, dissolved oxygen, inorganic nutrients, CFCs, total CO2,
pCO2, pH, C-13, C-14, O-18, helium, tritium, total alkalinity, dissolved
organic carbon, and dissolved organic nitrogen.  Sample protocols conformed to
those specified by the WOCE Hydrographic Programme.

     A Sea-Bird 11plus deck unit received the data signal from the CTD.  The
analog data stream was recorded onto video cassette tape as a backup.
Digitized data were forwarded to a 286-AT personal computer equipped with
SEASOFT acquisition and processing software version 4.201.  Temperature,
salinity, and oxygen profiles were displayed in real-time.  Raw data files were
transferred to a 486 personal computer using Laplink version 3 and backed up
onto 1/4" cartridge tapes using a Microsolutions Backpack QIC-80 external tape
drive.


C.1.2.a. Data Acquisition Problems

     During leg 2, station spacing increased to 40 nm between 58.5S and 48S
owing to a delay in departure from Punta Arenas, delays owing to winch problems
for some casts, and bad weather.  About 36 hours were lost waiting for the
weather to moderate at 58S.  Other problems included poor level winding of the
winch resulting in non-uniform lays on the drum and high tension crossing and
snapping of the cable, compromised chemistry samples owing to contamination
from the ship's stack output, and difficulties associated with doing CTDs from
the stern of the ship in heavy to moderate seas at high latitudes.

     Stations 8 and 9 test casts were very noisy.  Modulo errors persisted
through cast 14.   Station 11 cast 1 did not sample the upper 800 meters and so
a second cast was performed at this station for these bottles.  Station 11 cast
2 CTD data was not processed.  Station 111 stopcocks and vents were left open
therefore no samples were collected.  At station 120, upcast water sampling was
skipped from 800 to 400 db while a fishing vessel cleared it's net out of the
water.  Prior to station 123, the cable was reterminated after cutting off 2500
m of cable to get below bad wraps.  At station 131 the package sat on the bottom
for several minutes.  The upcast CTD data were bad.  Uptrace pressures were
matched to downtrace pressures for bottle sample CTD data.  Station 160 had
increasing modulo errors during the downcast and was aborted.  Water was found
in the ground wire at the termination.  No samples collected at station 160.
There was no sample from station 190 bottle 11 owing to a stuck lanyard.

C.1.2.b.  Salinity Analyses

     Bottle salinity analyses were performed in a temperature-controlled van
using two Guildline Model 8400A inductive autosalinometers standardized with
IAPSO Standard Seawater batch P114.  The autosalinometer in use was
standardized before each run and either at the end of each run or after no more
than 48 samples.  The drift between standardizations was monitored and the
individual samples were corrected for that drift by linear interpolation.
Duplicate samples taken from the deepest bottle on each cast were analyzed on
a subsequent day.  Bottle salinities were compared with preliminary CTD
salinities to aid in identification of leaking bottles as well as to monitor
the CTD conductivity cells' performance and drift.

     The expected precision of the autosalinometer with an accomplished operator
is 0.001 pss, with an accuracy of 0.003.  To assess the precision of discrete
salinity measurements on this cruise, a comparison was made for data from the
instances in which two bottles were tripped within 10 dbar of each other at the
same station below a depth of 2000 dbar.  For the 138 instances in which both
bottles of the pair have acceptable salinity measurements, the standard
deviation of the differences is 0.0012 pss.  This value is very close to the
expected precision.

    Calibrated CTD salinities replace missing bottle salinities in the
hydrographic data listing and are indicated by an asterisk.


C.1.3.  POST-CRUISE CALIBRATIONS

     Post-cruise sensor calibrations were done at Sea-Bird Electronics, Inc.
during May 1994.  For stations 2-8, temperature sensor T1455 (with pre-cruise
calibration coefficients dated January 1994) and conductivity sensor C1177
(with pre-cruise calibration coefficients dated September 1993) were selected
as the best source of data.  Post-cruise calibrations showed T1455 had drifted
(offset only) by approximately -0.0015; C1177 displayed a change in slope.
For stations 9-194, sensor T1461 (with pre-cruise calibration coefficients
dated January 1994) and C1247 (with pre-cruise calibration coefficients dated
January 1994) were selected for final data reduction since they were used on
both packages.  Post-cruise calibrations showed T1461 to be drifting (offset
only) by approximately -0.006 C.  C1247 had drifted (slope and offset) by
approximately -0.0009 S/m.

     At sea monitoring and post-cruise calibration of redundant TC pair
T1460/C1180 showed T1460 had jumped by 0.002 C, warranting repair.  Redundant
TC pair T1072/C748 post-cruise calibration showed T1072 had drifted to an
offset of -0.004 C.  These TC pairs were not included in the final processing.

C.1.3.a.  Conductivity

     SEASOFT module ALIGNCTD was used to align conductivity measurements in
time relative to pressure.  Measurements can be misaligned due to the inherent
time delay of the sensor response, the water water transit time delay in the
pumped plumbing line, and the sensors being physically misaligned in depth.
Because SBE 3 temperature response is fast (0.06 seconds), it is not necessary
to advance temperature relative to pressure.  When measurements are properly
aligned, salinity spiking and density errors are minimized.

     For a SBE 9 CTD with ducted TC sensors and a 3000 rpm pump the typical net
advance of conductivity relative to temperature is 0.073 seconds.  The SBE 11
deck units advanced primary conductivity 0.073 seconds but do not advance
secondary conductivity.  Therefore when C1177 or C1247 conductivity data came
from a secondary sensor channel the alignment was much larger, typically 0.06
seconds versus coming from a primary sensor channel, typically 0.02 seconds.

     Conductivity slope and bias, along with a pressure fudge term (beta) were
computed by a least-squares minimization of CTD and bottle conductivity
differences.  The function minimized was

			BC - m * CC - b - beta * CP

where BC is bottle conductivity (S/m), CC is pre-cruise calibrated CTD
conductivity (S/m), CP is the CTD pressure (dbar), m is the conductivity slope,
b is the bias (S/m), and beta is the pressure fudge term (S/m/dbar).  The final
CTD conductivity (S/m) is

			m * CC + b + beta * CP

The slope term m is a fourth-order polynomial function of station number to
allow the entire cruise to be fit at once with a smoothly-varying station-
dependent slope correction.  For each sensor a series of fits were made, each
fit throwing out bottle values for locations having a residual between CTD and
bottle conductivities of greater than three standard deviations.  This
procedure was repeated with the remaining bottle values until no more bottle
values were thrown out.

     For C1177, the slope correction ranged from 1.00014254 to 1.00014262, the
bias applied was -3.8e-4, and the beta term was -5.69e-9.  Of 5040 bottles, the
percentage of bottles retained in the fit was 84.9 with a standard deviation of
CTD versus bottle conductivity differences of 1.19e-4 S/m.  For C1247, the
slope correction ranged from 1.00021478 to 1.00044972, the bias applied was
-7.2e-4, and the beta term was -1.29e-8.  Of 5797 bottles, the percentage of
bottles retained in the fit was 83.4 with a standard deviation of 0.87e-4 S/m.
The slope and bias were applied in SEACON.  The beta-fudge term was applied
after SEASOFT post-processing in PMEL program POSTCAL.

     CTD-bottle conductivity differences used for the final fits are
plotted against cast number to show the stability of the calibrated CTD
conductivities relative to the bottle conductivities.  The entire set of
CTD-bottle conductivity differences are plotted against pressure to show
the tight fit below 1000 m and the increasing scatter above 1000 m.

C.1.3.b.  Temperature

     In SEACON, adjustments were made to the bias of the thermistors as
deviations from the pre-cruise calibrations on a station by station basis.
These deviations were obtained from a linear fit of the pre-cruise and post-
cruise temperature residuals from the pre-cruise calibration versus time.
Deep temperature differences between primary and secondary sensors were less
than 0.001 C.

     Also, a uniform correction for heating of the thermistor owing to viscous
effects was applied to the bias in SEACON.  This correction was obtained using
the formula:

			error[C] = B * sqrt(nu)*U*U

where B=0.692, U=1.02 m/s, and nu=1.7279e-6 m2/s.  The value for viscosity
nu is that for the peak in the distribution of the temperature and salinity
bottle values (te=1.8 C, sa=34.67 pss).  Error[C] = 0.9464e-3 C.  All the
thermistors read high by this amount and were adjusted down accordingly.  The
adjustment is near the maximum viscous heating for the encountered temperature
and salinity range.  Thermistors will read about 0.66e-3 C high near the
surface in the tropics (te=30 C, sa=34.5 pss) causing an overadjustment of
0.29e-3 C.  For deep values (te=0 C, sa=37 pss) where gradients are small,
thermistors will read about 0.97e-3 C high and so will be underadjusted by
0.2e-3 C.

C.1.3.c.  Oxygen

     In situ oxygen samples collected during CTD profiles are used for
post-measurement calibration.  SEASOFT bottle files were merged and bottle
oxygen values flagged as 'good' were appended to the data records.  Because the
dissolved oxygen sensor has an obvious hysteresis, PMEL program OXDWNP replaced
up-profile water sample data with corresponding down-profile CTD/O2 data at
common pressure levels.  Oxygen saturation values were computed according to
Benson and Krause (1984) in units of umol/kg.

     The algorithm used for converting oxygen sensor current and probe
temperature measurements to oxygen as described by Owens and Millard (1985)
requires a non-linear least squares regression technique in order to determine
the best fit coefficients of the model for oxygen sensor behavior to the water
sample observations.  WHOI program OXFITMR uses Numerical REcipes (Press et
al., 1986) Fortran routines MRQMIN, MRQCOF, GAUSSJ, and COVSRT to perform
non-linear least squares regression using Levenberg-Marquardt method.  A
Fortran subroutine FOXY describes the oxygen model with the derivatives of the
model with respect to six coefficients in the following order:  oxygen current
slope, temperature correction, pressure correction, weight, oxygen current
bias, and oxygen current lag.

     Program OXFITMR reads the data for a group of stations.  The time rate of
change of oxygen current is computed using a least squares estimate over 15
second intervals.  The data are editted to remove spurious points where values
are less than zero or greater than 1.2 times the saturation value.  The routine
varies the six (or fewer) parameters of the model in such a way as to produce
the minimum sum of squares in the difference between the calibration oxygens
and the computed values.  Individual differences between the calibration oxygens
and the computed oxygen values (residuals) are then compared with the standard
deviation of the residuals.  Any residual exceeding an edit factor of 2.8
standard deviations is rejected.  A factor of 2.8 will have a 0.5% chance of
rejecting a valid oxygen value for a normally distributed set of residuals.
The iterative fitting process is continued until none of the data fail the edit
criteria.  The best fit to the oxygen probe model coefficients is then
determined.  Coefficents were applied by PMEL program CALOX2W and CTD oxygen was
computed using subroutine OXY6W.

     By plotting the oxygen residuals versus station, appropriate station
groupings for further refinements of fitting were obtained by looking for abrupt
station to station changes in the residuals.  Sometimes it was necessary to fix
values of some oxygen algorithm parameters to keep those parameters within a
reasonable range.  Final coefficients were applied by PMEL program EPSBE94.


C.1.4.  POST-CRUISE PROCESSING

     SEASOFT consists of modular menu driven routines for acquisition, display,
processing, and archiving of oceanographic data acquired with Sea-Bird
equipment and is designed to work with an IBM or compatible personal computer.
Raw data is acquired from the instruments and is stored as unmodified data.
The conversion module DATCNV uses the instrument configuration and calibration
coefficients to create a converted engineering unit data file that is operated
on by all SEASOFT post processing modules.  Each SEASOFT module that modifies
the converted data file adds information to the header of the converted file
permitting tracking of how the various oceanographic parameters were obtained.
The converted data is stored in either rows and columns of ascii numbers or as
a binary data stream with each value stored as a 4 byte binary floating point
number.  The last data column is a flag field used to mark scans as good or bad.

     The following are the SEASOFT processing module sequence and specifications
used in the reduction of P18 CTD/O2 data.

     DATCNV converted the raw data to pressure, temperature, conductivity,
oxygen current, oxygen temperature, and transmissometer voltage.  DATCNV also
extracted bottle information where scans were marked with the bottle confirm
bit during acquisition.

     ROSSUM created a summary of the bottle data.  Bottle position, date, and
time were output as the first two columns.  Pressure, temperature, conductivity,
oxygen current, oxygen temperature, and transmissometer voltage were averaged
over a two-second interval (48 scans).  For the primary package, the time
interval was from five to three seconds prior to the confirm bit in order to
avoid spikes in conductivity and oxygen current owing to minor incompatibilities
between the Sea-Bird 911plus CTD system and General Oceanics 1016 rosette.
Bottle data from the backup package were averaged from one second prior to the
confirm bit to 1 second after the confirm bit in the data stream.

     WILDEDIT marked extreme outliers in the data files.  The first pass of
WILDEDIT obtained an accurate estimate of the true standard deviation of the
data.  The data were read in blocks of 200 scans.  Data greater than two
standard deviations were flagged.  The second pass computed a standard
deviation over the same 200 scans excluding the flagged values.  Values greater
than 16 standard deviations were marked bad.

     SPLIT removed decreasing pressure records from the data files leaving
only the downcast.

     FILTER performed a low pass filter on pressure with a time constant of
0.15 seconds.  In order to produce zero phase (no time shift) the filter first
runs forward through the file and then runs backwards through the file.

     ALIGNCTD aligned conductivity in time relative to pressure to ensure that
all calculations were made using measurements from the same parcel of water.
Alignment between stations was checked every time the CTD configuration changed
between primary and secondary underwater packages or every ten stations,
whichever was less.

     CELLTM used a recursive filter to remove conductivity cell thermal mass
effects from the measured conductivity.  Typical values were used for thermal
anomaly amplitude (alpha=0.03) and the time constant (1/beta=9.0).

     DERIVE was used to compute fall rate (m/s) with a time window size for
fall rate and acceleration of 2.0 seonds.

     LOOPEDIT marked scans where the CTD was moving less than the minimum
velocity of 0.2 m/s or travelling backwards due to ship roll.

     BINAVG averaged the data into 1 db pressure bins starting at 1 db with no
surface bin.  The center value of the first bin was set equal to the bin size.
The bin minimum and maximum values are the center value +/- half the bin size.
Scans with pressures greater than the minimum and less than or equal to the
maximum were averaged.  Scans were interpolated so that a data record exists
every decibar.

     STRIP removed scan number and fall rate from the data files.

     TRANS converted the data file format from binary to ascii.

     Following the SEASOFT processing modules, PMEL program POSTCAL corrected
conductivity with respect to pressure using an additional beta term,

          beta  = -1.29e-8  for C1247
          beta  = -5.69e-8  for C1177
          c2(i) = (c1(i)*10) + beta * p(i)

computed salinity,

          s(i) = SAL78(c2(i)/42.914,t1(i),p(i),0)

corrected temperature due to instrument calibration error,

          t2(i) = 1.00008961734348 * t1(i) - 9.924374518041036e-4

and backed out final conductivity values.

          c3(i) = SAL78(s(i),t2(i),p(i),1)
          c3(i) = c3(i) * 42.914

Also, POSTCAL interpolated temperature, conductivity, oxygen current, oxygen
temperature, and transmissometer voltage where values were bad as flagged by
SEASOFT before the above corrections and repeated to the surface the first good
record input interactively by the user.

     PMEL program EPSBE94 followed POSTCAL and computed doxc/dt, calibrated
CTD oxygens, and computed ITS-90 temperature, potential temperature, sigma-t,
sigma-theta, and dynamic height.  EPSBE94 also introduced the WOCE quality
flag associated with pressure, temperature, salinity, and CTD oxygen.  Quality
flag definitions can be found in the WOCE Operations Manual (1994).  1 db data
were output in EPIC format (Soreide, 1995).  Processed data were despiked and
values linearly interpolated.  WOCE flags were ammended to reflect these
changes.



D. 	Acknowledgments

    The assistance of the officers, crew, and survey department of the NOAA
ship DISCOVERER is gratefully acknowledged.  Funds for the CTD/O2 program were
provided to PMEL by the Climate and Global Change program under NOAA's Office
of Global Programs.


E.	References

Benson, B.B. and D. Krausse Jr., 1984 : The concentration and isotopic
	fractionation of oxygen dissolved in freshwater and seawater in
	equilibrium with the atmosphere.  Limnology and Oceanography, 29,
	620-632.

Denbo, D.W., 1992 : PPLUS Graphics, P.O. Box 4, Sequim, WA, 98382.

Owens, W.B. and R.C. Millard Jr., 1985 : A new algorithm for CTD oxygen
	calibration.  J. Physical Oceanography, 15, 621-631.

Seasoft CTD Aquisition Software Manual, 1994 : Sea-Bird Electronics, Inc.,
	1808 136th Place NE, Bellevue, Washington, 98005.

Soreide, N.N., M.L. Schall, W.H. Zhu, D.W. Denbo and D.C. McClurg, 1995 :
	EPIC:  An oceanographic data management, display and analysis system.
	Proceedings, 11th International Conference on Interactive Information
	and Processing Systems for Meteorology, Oceanography, and Hydrology,
	January 15-20, 1995, Dallas, TX, 316-321.

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.

WOCE Operations Manual, 1994 :  Volume 3: The Observational Programme,
	Section 3.1: WOCE Hydrographic Programme, Part 3.1.2: Requirements
	for WHP Data Reporting.  WHP Office Report 90-1, WOCE Report No.
	67/91, Woods Hole, MA, 02543.

F.	WHPO Summary

 Several data files are associated with this report.  They are the
31DSCG94_2.sum and 31DSCG94_3.sum, 31DSCG94_2.hyd and 31DSCG94_3.hyd,
31DSCG94_2.csl and 31DSCG94_3.csl and *.wct files.  The *.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.  When submitted to the SAC, the *.wct files
are zipped into one file called *wct.zip. The *.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 coriolius 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.