US JGOFS Antarctic Environments Southern Ocean Process Study (AESOPS)
 
Palmer Leg 97-01; Jan. - Feb. 1997; Process 2


John M. Morrison
2 February 1998

This "readme" file pertains to the CTD data taken
during RV N. B. Palmer cruise NBP9701 in January - February 1997.
Dr. John Marra of the Lamont Doherty Earth Observatory of Columbia 
University (marra@lamont.ldeo.columbia.edu) was the
chief scientist during this leg.

This cruise was the second process study leg
of the U.S. JGOFS program in the Southern Ocean (AESOPS).

CTD Calibration:

On this cruise, one CTD configuration was used.  The processing
and calibration information for this configuration is given below:
 
The casts made with the Trace Metal Clean Rosette makde on this leg are not
reported here because this system was not designed to produce CTD data of
"WOCE" quality.  The CTD system on this rosette was not capable of the
precision obtained from the system on the hydrographic rosette. It was 
determined that the CTD dissolved oxygen sensor did not produce reliable
data on this cruise.  The CTD transmissometer, fluorometer, light scattering
and PAR measurements are currently being calibrated by other investigators.

There were spikes in the data at a number of stations on this cruise that
appeared to be due to problems with the CTD cable or o-rings.  These
spikes have been hand-edited out of the final data set.

In addition, there appeared to be some flushing problems with the 
nisken bottles in the high gradient region near the surface.  Therefore,
the data collected below the high gradient region were used in the
calibration of the CTD sensor.
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SEA-BIRD Processing Information:  Example 97120101.CNV
 
* Sea-Bird SBE 9 Raw Data File:
* FileName = G:\97120101.DAT
* Software Version 4.218
* Temperature SN = 1649
* Conductivity SN = 1143
* Number of Bytes Per Scan = 30
* Number of Voltage Words = 4
* System UpLoad Time = Jan 13 1997 05:17:41
* NMEA Latitude = 76 29.96 S
* NMEA Longitude = 169  0.14 E
* NMEA UpLoad Time = not available
* Store Lat/Lon Data = Add to Header Only
** Ship: R/V Nathaniel B. Palmer 
** Cruise: JGOFS Southern Ocean 
# nquan = 19
# nvalues = 723                         
# units = metric
# name 0 = scan: scan number
# name 1 = t068: temperature, pri, IPTS-68 [deg C]
# name 2 = t168: temperature, sec, IPTS-68 [deg C]
# name 3 = pr: pressure [db]
# name 4 = c0mS/cm: conductivity, primary [mS/cm]
# name 5 = c1mS/cm: conductivity, secondary [mS/cm]
# name 6 = xmiss: transmissometer
# name 7 = stLs6000: sea tech ls6000 [mg/l]
# name 8 = par: irradiance (PAR)
# name 9 = oxML/L: oxygen [ml/l]
# name 10 = flC: fluorometer, chelsea
# name 11 = depS: depth, salt water [m]
# name 12 = potemp068: potential temperature, pri, IPTS-68 [deg C]
# name 13 = sal00: salinity, PSS-78 [PSU], T0, C0
# name 14 = gpa: geopotential anomaly
# name 15 = dm: dynamic meters
# name 16 = sigma-00: density, sigma-theta [kg/m^3], T0, C0
# name 17 = sigma-t00: density, sigma-t [kg/m^3], T0, C0
# name 18 = flag:  0.000e+00
# span 0 = 581, 20118                   
# span 1 = -1.8977, 0.5751              
# span 2 = -1.8957, 0.5765  
# span 3 = 3.000, 725.000               
# span 4 = 27.257195, 29.029066         
# span 5 = 27.257914, 29.031448         
# span 6 = 65.59, 91.29                 
# span 7 = 0.52801, 7.38413             
# span 8 = 6.494e-02, 1.002e+01         
# span 9 = 6.28337, 9.87789             
# span 10 = 4.180e-03, 9.866e+00        
# span 11 = 2.969, 716.169              
# span 12 = -1.9100, 0.5744             
# span 13 = 34.2289, 34.8044            
# span 14 = 0.000, 0.971                
# span 15 = 0.0000, 0.0971              
# span 16 = 27.4532, 28.0251            
# span 17 = 27.4531, 28.0246            
# span 18 = 0.000e+00, 0.000e+00        
# interval = decibars: 1                                
# start_time = Jan 13 1997 05:17:41
# bad_flag = -9.990e-29
# sensor 0 = Frequency  0  temperature, primary, 1649, 22-Feb-96 
# sensor 1 = Frequency  1  conductivity, primary, 1143, 01-nov-96, cpcor = -9.5700e-08
# sensor 2 = Frequency  2  pressure, 43528, 27-Jan-95
# sensor 3 = Frequency  3  temperature, secondary, 1541, 11 Feb 95
# sensor 4 = Frequency  4  conductivity, secondary, 0924, 01-Nov-96, cpcor = -9.5700e-08
# sensor 5 = Extrnl Volt  0  oxygen, current, 4-09-07, 31 January 1996
# sensor 6 = Extrnl Volt  1  oxygen, temperature, 4-09-07, 31 January 1996
# sensor 7 = Extrnl Volt  2  transmissometer, 207d, 23 Feb 1996
# sensor 8 = Extrnl Volt  3  fluorometer, chelsea, 88/2050-93, 23-Feb-96
# sensor 9 = Extrnl Volt  4  sea tech ls6000, 326, 05-17-96
# sensor 10 = Extrnl Volt  5  irradiance (PAR), 4361, 27-Jan-95
# datcnv_date = Jan 16 1997 20:19:20, 4.218
# datcnv_in = 97120101.DAT CTD_24.CON
# datcnv_skipover = 0
# wildedit_date = Jan 16 1997 20:21:38, 4.218
# wildedit_in = 97120101.CNV
# wildedit_pass1_nstd = 2.0
# wildedit_pass2_nstd = 20.0
# wildedit_npoint = 100
# wildedit_vars = scan t068 t168 pr c0mS/cm c1mS/cm xmiss stLs6000 par oxML/L flC
# wildedit_excl_bad_scans = yes
# celltm_date = Jan 16 1997 20:23:48, 4.218
# celltm_in = 97120101.CNV
# celltm_alpha = 0.0300, 0.0000
# celltm_tau = 7.0000, 0.0000
# filter_date = Jan 16 1997 20:25:58, 4.218
# filter_in = 97120101.CNV
# filter_low_pass_tc_A = 0.030
# filter_low_pass_tc_B = 0.150
# filter_low_pass_A_vars = c0mS/cm c1mS/cm
# filter_low_pass_B_vars = pr
# loopedit_date = Jan 16 1997 20:29:22, 4.218
# loopedit_in = 97120101.CNV
# loopedit_minVelocity = 0.250          
# loopedit_excl_bad_scans = yes
# binavg_date = Jan 16 1997 20:30:47, 4.218
# binavg_in = 97120101.CNV
# binavg_bintype = Pressure Bins
# binavg_binsize = 1.00
# binavg_excl_bad_scans = yes
# binavg_downcast_only = yes
# binavg_skipover = 0
# binavg_surface_bin = yes, min = 0.300, max = 0.500, value = 0.000
# derive_date = Jan 16 1997 20:31:19, 4.218
# derive_in = 97120101.CNV CTD_24.CON
# file_type = ascii
*END*
 
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Calibration:
 
Calibration for Conductivity and Salinity:
 
The CTD Conductivity sensor was calibrated by correlating the CTD
downcast conductivities with the conductivities of the water samples
taken with the SEA-BIRD carousel on the upcast. The mean and 
standard deviations of these differences using all of the available
bottle data are given below. Only the salinities collected below 
100 meters depth were used in this correlation. If full range was used 
the mean remains the same, the the STDEV increases as would be
expected for the high-gradient, variable surface layers.  Subsets of 
these data were also used to see if there was any significant
drift of the CTD sensors during the cruise. In this case there was
a signigicant drift in the sensors during the cruise.  As a result, 
the stations were divided into 2 sub-sets and different calibrations
were applied to each subset.
 
SUBSET 1:  97120101.cnf - 97121202.cnf
 
MINIMUM DEPTH USED =    100.0
 
Conductivity   STDEV=   0.002     MEAN=  -0.002
Salinity       STDEV=   0.002     MEAN=  -0.003
 
Therefore, a correction of .006 was applied to the CTD conductivities.
 
The reported Conductivities and Salinities are good to +/- .002.
 
SUBSET 2:  97121301.cnf - 97122807.cnf
 
MINIMUM DEPTH USED =    100.0
 
Conductivity   STDEV=   0.002     MEAN=  -0.003
Salinity       STDEV=   0.002     MEAN=  -0.005
 
Therefore, a correction of .006 was applied to the CTD conductivities.
 
The reported Conductivities and Salinities are good to +/- .002.

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The Digital dissolved oxygen sensor did not provide reliable data 
during this cruise.   The CTD transmissometer, fluorometer, light 
scattering and PAR measurements are currently being calibrated by 
other investigators.

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The raw data files may be requested from:

        DR.JOHN M. MORRISON
        NORTH CAROLINA STATE UNIVERSITY
        DEPARTMENT OF MARINE, EARTH AND ATMOSPHERIC SCIENCES
        JORDAN HALL RM. 1125
        BOX 8208
        RALEIGH, NC 27695-8208

        EMAIL:  John_Morrison@NCSU.EDU
        PHONE:  919-515-7449
        FAX:    919-515-7802