John M. Morrison -- 23 April 1996

TN049:  JGOFS Arabian Sea Process Study -- Process Cruise #4:

This "readme" file pertains to the CTD data taken
during RV T.G.  Thompson cruise TN049.  This cruise was the
fourth JGOFS Arabian Sea Process Leg and took place during July - August
1995.  Dr. Richard Barber of Duke University Marine Laboratory
(rbarber@mail.duke.edu) was the chief scientist.

CTD Calibration:

On this cruise, one CTD configurations was used.  The processing
and calibration information for this configuration is given
in  as follows:

Processing and calibation information for the initial setup of the CTD for 
cruise TN049.  See special section for station 04903101.

Sea-Bird Processing Information:  Example from 04900101.cnv

* Sea-Bird SBE 9 Raw Data File:
* FileName = G:\04900101.DAT
* Software Version 4.205
* Temperature SN = 1316
* Conductivity SN = 1371
* Number of Bytes Per Scan = 37
* Number of Voltage Words = 4
* System UpLoad Time = Jul 18 1995 02:48:39
* NMEA Latitude = 22 23.11 N
* NMEA Longitude = 059 52.95 E
* NMEA UpLoad Time = not available
* Store Lat/Lon Data = Add to Header and Append to Every Scan
* Ship: R/V Thomas G. Thompson
* Cruise: JGOFS Process 4
*         TNO49
# nquan = 16
# nvalues = 507
# units = metric
# name 0 = t068: temperature, pri, IPTS-68 [deg C]
# name 1 = c0mS/cm: conductivity, primary [mS/cm]
# name 2 = pr: pressure [db]
# name 3 = t168: temperature, sec, IPTS-68 [deg C]
# name 4 = c1mS/cm: conductivity, secondary [mS/cm]
# name 5 = oxML/L: oxygen [ml/l]
# name 6 = xmiss: transmissometer
# name 7 = flS: fluorometer, sea tech
# name 8 = par: irradiance (PAR)
# name 9 = depS: depth, salt water [m]
# name 10 = potemp068: potential temperature, pri, IPTS-68 [deg C]
# name 11 = sigma-t00: density, sigma-t [kg/m^3], T0, C0
# name 12 = sigma-é00: density, sigma-theta [kg/m^3], T0, C0
# name 13 = sal00: salinity, PSS-78 [PSU], T0, C0
# name 14 = sal11: salinity, PSS-78 [PSU], T1, C1
# name 15 = flag:  0.000e+00
# span 0 = 16.2454, 23.9580
# span 1 = 45.589108, 53.494190
# span 2 = 2.000, 255.000
# span 3 = 16.2180, 23.9365
# span 4 = 45.564072, 53.468842
# span 5 = -0.01548, 2.96546
# span 6 = 79.31, 90.00
# span 7 = 1.933e-01, 3.710e+00
# span 8 = 4.284e+01, 6.596e+02
# span 9 = 1.987, 253.249
# span 10 = 16.2042, 23.9575
# span 11 = 24.5259, 26.6059
# span 12 = 24.5261, 26.6154
# span 13 = 35.7929, 36.4421
# span 14 = 35.7890, 36.4424
# span 15 = 0.000e+00, 0.000e+00
# interval = decibars: 1
# start_time = Jul 18 1995 02:48:39
# bad_flag = -9.990e-29
# serial_numbers = t0:1316, c0:1371, pr:57657, t1:1605, c1:1084, ox:130229, flS:
84, xmiss:148D, obs:241, par:7176
# datcnv_date = Jul 19 1995 12:04:13, 4.205
# datcnv_in = 04900101.DAT CTD_24.CON 1316 1371 57657
# datcnv_skipover = 0
# wildedit_date = Jul 19 1995 12:06:39, 4.205
# wildedit_in = 04900101.CNV
# wildedit_pass1_nstd = 2.0
# wildedit_pass2_nstd = 20.0
# wildedit_npoint = 100
# wildedit_vars = t068 c0mS/cm pr t168 c1mS/cm oxML/L xmiss flS par
# wildedit_excl_bad_scans = yes
# celltm_date = Jul 19 1995 12:07:36, 4.205
# celltm_in = TEMP.CNV
# celltm_alpha = 0.0300, 0.0000
# celltm_tau = 9.0000, 0.0000
# filter_date = Jul 19 1995 12:08:23, 4.205
# filter_in = 04900101.CNV
# filter_low_pass_tc_A = 0.150
# filter_low_pass_tc_B = 0.100
# filter_low_pass_A_vars = pr
# filter_low_pass_B_vars =
# loopedit_date = Jul 19 1995 12:10:02, 4.205
# loopedit_in = TEMP.CNV
# loopedit_minVelocity = 0.000
# loopedit_excl_bad_scans = yes
# binavg_date = Jul 19 1995 12:11:09, 4.205
# binavg_in = 04900101.CNV
# binavg_bintype = Pressure Bins
# binavg_binsize = 1.00
# binavg_excl_bad_scans = yes
# binavg_downcast_only = no
# binavg_skipover = 0
# binavg_surface_bin = yes, min = 0.500, max = 0.500, value = 0.000
# derive_date = Jul 19 1995 12:11:59, 4.205
# derive_in = TEMP.CNV CTD_24.CON
# file_type = ascii
*END*

The same salinity correction has been applied for all of the stations on Cruise
TN049. From the analysis of the data, we decided to apply different corrections
to the data in the high salinity gradient region (0 - 499 meters in depth) and
the deep water column ( 500 - bottom).

Corrected CTD Salinity = Observed CTD Salinity - Sal Correction (Defined Below)

Shallow Correction:

   MINIMUM DEPTH USED =       0.00000
   MAXIMUM DEPTH USED =       499.000

   Sal Correction = 0.0049286497 - 3.4764706e-05 * PR + 5.6925728e-08 * PR * PR

   Standard Deviation of Fit =     0.0122

Deep Correction:

   MINIMUM DEPTH USED =       500.000
   MAXIMUM DEPTH USED =       4470.70

   Sal Correction = 0.00014260912 - 2.2297606e-06 * PR + 6.3299571e-10 * PR * PR

   Standard Deviation of Fit =     0.0017

Therefore in the upper 500 meters, the corrected CTD salinities are good to at 
least +/- .012, while in the deep water the calibrated CTD salinities are
good to +/- .0017.  

We expect that the upper layer salinities are better than +/- .012, 
but because of the natural variability between in this region, this is
the best that we are able to determine from calibration.


Special processing for station 04903101.............
John M. Morrison 24 May 1996

Apparently on Station 04903101 the primary salinity sensor malfunctioned for 
the first 90 meters or so (most likely due to something being in the sensor.  
Therefore, the secondary set of sensors was used for this station.  

Sea-Bird Processing Information: 04903101.cnv

* Sea-Bird SBE 9 Raw Data File:
* FileName = G:\04903101.DAT
* Software Version 4.205
* Temperature SN = 1316
* Conductivity SN = 1371
* Number of Bytes Per Scan = 37
* Number of Voltage Words = 4
* System UpLoad Time = Aug 12 1995 17:04:15
* NMEA Latitude = 18 39.00 N
* NMEA Longitude = 057 45.10 E
* NMEA UpLoad Time = not available
* Store Lat/Lon Data = Add to Header and Append to Every Scan
* Ship: R/V Thomas G. Thompson
* Cruise: JGOFS Process 4
*         TNO49
# nquan = 19
# nvalues = 498
# units = metric
# name 0 = t068: temperature, pri, IPTS-68 [deg C]
# name 1 = c0mS/cm: conductivity, primary [mS/cm]
# name 2 = pr: pressure [db]
# name 3 = t168: temperature, sec, IPTS-68 [deg C]
# name 4 = c1mS/cm: conductivity, secondary [mS/cm]
# name 5 = oxML/L: oxygen [ml/l]
# name 6 = xmiss: transmissometer
# name 7 = flS: fluorometer, sea tech
# name 8 = par: irradiance (PAR)
# name 9 = depS: depth, salt water [m]
# name 10 = potemp068: potential temperature, pri, IPTS-68 [deg C]
# name 11 = potemp168: potential temperature, sec, IPTS-68 [deg C]
# name 12 = sigma-é00: density, sigma-theta [kg/m^3], T0, C0
# name 13 = sigma-é11: density, sigma-theta [kg/m^3], T1, C1
# name 14 = sigma-t00: density, sigma-t [kg/m^3], T0, C0
# name 15 = sigma-t11: density, sigma-t [kg/m^3], T1, C1
# name 16 = sal00: salinity, PSS-78 [PSU], T0, C0
# name 17 = sal11: salinity, PSS-78 [PSU], T1, C1
# name 18 = flag:  0.000e+00
# span 0 = 15.2137, 23.1049
# span 1 = 44.157951, 52.008209
# span 2 = 3.000, 252.000
# span 3 = 15.2148, 23.1044
# span 4 = 44.156597, 52.005978
# span 5 = 0.03035, 4.03314
# span 6 = 80.07, 88.39
# span 7 = 1.678e-01, 5.833e+00
# span 8 = 4.287e+01, 4.287e+01
# span 9 = 2.982, 250.328
# span 10 = 15.1749, 23.1041
# span 11 = 15.1759, 23.1029
# span 12 = 23.5892, 26.5797
# span 13 = 24.4366, 26.5778
# span 14 = 23.5890, 26.5711
# span 15 = 24.4361, 26.5691
# span 16 = 34.4958, 37.1759
# span 17 = 35.5695, 35.8365
# span 18 = 0.000e+00, 0.000e+00
# interval = decibars: 1
# start_time = Aug 12 1995 17:04:15
# bad_flag = -9.990e-29
# serial_numbers = t0:1316, c0:1371, pr:57657, t1:1605, c1:1084, ox:130229, flS:
84, xmiss:148D, obs:241, par:7176
# datcnv_date = Aug 12 1995 18:31:55, 4.205
# datcnv_in = 04903101.DAT CTD_24.CON 1316 1371 57657
# datcnv_skipover = 0
# wildedit_date = Aug 12 1995 18:34:11, 4.205
# wildedit_in = 04903101.CNV
# wildedit_pass1_nstd = 2.0
# wildedit_pass2_nstd = 20.0
# wildedit_npoint = 100
# wildedit_vars = t068 c0mS/cm pr t168 c1mS/cm oxML/L xmiss flS par
# wildedit_excl_bad_scans = yes
# celltm_date = Aug 12 1995 18:35:03, 4.205
# celltm_in = TEMP.CNV
# celltm_alpha = 0.0300, 0.0000
# celltm_tau = 9.0000, 0.0000
# filter_date = Aug 12 1995 18:35:47, 4.205
# filter_in = 04903101.CNV
# filter_low_pass_tc_A = 0.150
# filter_low_pass_tc_B = 0.100
# filter_low_pass_A_vars = pr
# filter_low_pass_B_vars =
# loopedit_date = Aug 12 1995 18:37:17, 4.205
# loopedit_in = TEMP.CNV
# loopedit_minVelocity = 0.000
# loopedit_excl_bad_scans = yes
# binavg_date = Aug 12 1995 18:38:18, 4.205
# binavg_in = 04903101.CNV
# binavg_bintype = Pressure Bins
# binavg_binsize = 1.00
# binavg_excl_bad_scans = yes
# binavg_downcast_only = no
# binavg_skipover = 0
# binavg_surface_bin = yes, min = 0.500, max = 0.500, value = 0.000
# derive_date = Aug 12 1995 18:41:06, 4.205
# derive_in = TEMP.CNV CTD_24.CON
# file_type = ascii
*END*

This station was calibrated by computing the mean difference between the bottle 
salinities and the "observed" ctd salinities from the secondary sensor 
below the high salinity gradient region (ie: the data from 80 to 250 m was used).

Conductivity   STDEV=  0.001     MEAN=   0.001
Salinity       STDEV=  0.001     MEAN=   0.001

Therefore, a correction of -.001 was applied to the shipboard Conductivities
and Salinities.

The reported Conductivities and Salinities are good to +/- .001.

OTHER PARAMETERS

Digital dissolved oxygen, transmissometer and fluoruometer data
were also collected on the CTD, but are not reported here
as we have not calibrated this data.

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