Morrison Notes on CTD

 
John M. Morrison -- 18 July 1996

TN053:  JGOFS Arabian Sea Process Study -- Process Cruise #6:

This "readme" file pertains to the CTD data taken
during RV T.G.  Thompson cruise TN053.  This cruise was the
sixth JGOFS Arabian Sea Process Leg and took place during October -
November 1995. Barney Balch of the Bigelow Laboratory for Ocean
Sciences (balch@phyto.bigelow.org) was the chief scientist.

Digital dissolved oxygen, transmissometer and fluorometer 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


CTD Calibration:

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

This the setup, processing and calibation information for the 
CTD for cruise TN053.

Sea-Bird Processing Information:  Example from 05300101.cnv

 Sea-Bird SBE 9 Raw Data File:
* FileName = G:\05300101.DAT
* Software Version 4.205
* Temperature SN = 748
* Conductivity SN = 399
* Number of Bytes Per Scan = 37
* Number of Voltage Words = 4
* System UpLoad Time = Oct 29 1995 10:04:40
* NMEA Latitude = 24 19.61 N
* NMEA Longitude = 058 10.47 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: Process 6
*         TNO53
# nquan = 19
# nvalues = 499
# 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 = 16.4068, 28.8880
# span 1 = 45.920315, 59.875965
# span 2 = 3.000, 252.000
# span 3 = 16.4190, 28.9069
# span 4 = 45.670555, 59.480927
# span 5 = -0.01998, 4.09781
# span 6 = 76.85, 90.73
# span 7 = 1.018e-01, 5.990e+00
# span 8 = 4.287e+01, 5.432e+02
# span 9 = 2.981, 250.238
# span 10 = 16.3659, 28.8873
# span 11 = 16.3781, 28.9059
# span 12 = 23.5087, 26.6903
# span 13 = 23.2857, 26.5095
# span 14 = 23.5084, 26.6806
# span 15 = 23.2854, 26.5001
# span 16 = 36.0416, 36.8791
# span 17 = 35.7979, 36.5893
# span 18 = 0.000e+00, 0.000e+00
# interval = decibars: 1
# start_time = Oct 29 1995 10:04:40
# bad_flag = -9.990e-29
# serial_numbers = t0:748, c0:399, pr:34901, t1:761, c1:478, ox:352,
stLs6000:24
1, xmiss:148D, flS:84D, par:7176
# datcnv_date = Oct 29 1995 11:19:52, 4.205
# datcnv_in = 05300101.DAT CTD_24.CON 748 399 34901
# datcnv_skipover = 0
# wildedit_date = Oct 29 1995 11:22:07, 4.205
# wildedit_in = 05300101.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 = Oct 29 1995 11:22:59, 4.205
# celltm_in = TEMP.CNV
# celltm_alpha = 0.0300, 0.0000
# celltm_tau = 9.0000, 0.0000
# filter_date = Oct 29 1995 11:23:43, 4.205
# filter_in = 05300101.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 = Oct 29 1995 11:25:16, 4.205
# loopedit_in = TEMP.CNV
# loopedit_minVelocity = 0.000
# loopedit_excl_bad_scans = yes
# binavg_date = Oct 29 1995 11:26:19, 4.205
# binavg_in = 05300101.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 = Oct 29 1995 11:27:05, 4.205
# derive_in = TEMP.CNV CTD_24.CON
# file_type = ascii
*END*

--------------------------------------------------------------------------------
There was a significant drift in the conductivity/salinity sensor on 
Cruise TN053.  Because of this the stations were calibrated in batches.
In addition, while the salinity correction below 500 was constant, there
is a signigicant trend in the correction within the upper 500 meters. 
Therefore, different corrections were applied to the data in the 
upper 500 meters and from 500 meters to the bottom.

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

Salinity corrections for each batch of stations are given below.

--------------------------------------------------------------------------------
Stations:
 
Stations 1a:

/jgofs/tn053/ctd/05300101.cnf
/jgofs/tn053/ctd/05300102.cnf
/jgofs/tn053/ctd/05300103.cnf
/jgofs/tn053/ctd/05300201.cnf
/jgofs/tn053/ctd/05300202.cnf
/jgofs/tn053/ctd/05300203.cnf
/jgofs/tn053/ctd/05300301.cnf
/jgofs/tn053/ctd/05300302.cnf
/jgofs/tn053/ctd/05300303.cnf
/jgofs/tn053/ctd/05300401.cnf
/jgofs/tn053/ctd/05300402.cnf
/jgofs/tn053/ctd/05300501.cnf
/jgofs/tn053/ctd/05300502.cnf
/jgofs/tn053/ctd/05300503.cnf
/jgofs/tn053/ctd/05300601.cnf
/jgofs/tn053/ctd/05300602.cnf
/jgofs/tn053/ctd/05300603.cnf
/jgofs/tn053/ctd/05300604.cnf
/jgofs/tn053/ctd/05300605.cnf
/jgofs/tn053/ctd/05300701.cnf
/jgofs/tn053/ctd/05300702.cnf
/jgofs/tn053/ctd/05300703.cnf
/jgofs/tn053/ctd/05300704.cnf
/jgofs/tn053/ctd/05300705.cnf
/jgofs/tn053/ctd/05300706.cnf
/jgofs/tn053/ctd/05300707.cnf
/jgofs/tn053/ctd/05300708.cnf
/jgofs/tn053/ctd/05300709.cnf
/jgofs/tn053/ctd/05300710.cnf
/jgofs/tn053/ctd/05300711.cnf
/jgofs/tn053/ctd/05300712.cnf
/jgofs/tn053/ctd/05300713.cnf
/jgofs/tn053/ctd/05300714.cnf
/jgofs/tn053/ctd/05300715.cnf
/jgofs/tn053/ctd/05300716.cnf

MINIMUM DEPTH USED =       0.00000
MAXIMUM DEPTH USED =       500.000 

Sal Correction     = -0.0041527407 + 4.2600272e-06 * Pressure
Standard Deviation =  0.01

MINIMUM DEPTH USED =       500.000
MAXIMUM DEPTH USED =       3023.40
                            
Sal Correction     = -0.0006
Standard Deviation =  0.01

Stations 1b:

/jgofs/tn053/ctd/05300801.cnf
/jgofs/tn053/ctd/05300802.cnf
/jgofs/tn053/ctd/05300803.cnf
/jgofs/tn053/ctd/05300804.cnf
/jgofs/tn053/ctd/05300805.cnf
/jgofs/tn053/ctd/05300901.cnf
/jgofs/tn053/ctd/05300902.cnf
/jgofs/tn053/ctd/05300903.cnf
/jgofs/tn053/ctd/05300904.cnf
/jgofs/tn053/ctd/05300905.cnf
/jgofs/tn053/ctd/05301001.cnf
/jgofs/tn053/ctd/05301002.cnf
/jgofs/tn053/ctd/05301003.cnf
/jgofs/tn053/ctd/05301004.cnf
/jgofs/tn053/ctd/05301005.cnf
/jgofs/tn053/ctd/05301006.cnf
/jgofs/tn053/ctd/05301007.cnf
/jgofs/tn053/ctd/05301008.cnf
/jgofs/tn053/ctd/05301009.cnf
/jgofs/tn053/ctd/05301010.cnf
/jgofs/tn053/ctd/05301011.cnf
/jgofs/tn053/ctd/05301012.cnf
/jgofs/tn053/ctd/05301013.cnf
/jgofs/tn053/ctd/05301014.cnf
/jgofs/tn053/ctd/05301015.cnf
/jgofs/tn053/ctd/05301016.cnf
/jgofs/tn053/ctd/05301018.cnf

MINIMUM DEPTH USED =       0.00000
MAXIMUM DEPTH USED =       500.000 

Sal Correction     = -0.0066297317 + 1.4336964e-05 * Pressure
Standard Deviation =  0.01

MINIMUM DEPTH USED =       500.000
MAXIMUM DEPTH USED =       3021.90

Sal Correction     = -0.003
Standard Deviation =  0.001

Stations 2:

/jgofs/tn053/ctd/05301101.cnf
/jgofs/tn053/ctd/05301102.cnf
/jgofs/tn053/ctd/05301201.cnf
/jgofs/tn053/ctd/05301301.cnf
/jgofs/tn053/ctd/05301302.cnf
/jgofs/tn053/ctd/05301303.cnf
/jgofs/tn053/ctd/05301304.cnf
/jgofs/tn053/ctd/05301305.cnf
/jgofs/tn053/ctd/05301306.cnf
/jgofs/tn053/ctd/05301307.cnf
/jgofs/tn053/ctd/05301308.cnf
/jgofs/tn053/ctd/05301309.cnf
/jgofs/tn053/ctd/05301310.cnf
/jgofs/tn053/ctd/05301311.cnf
/jgofs/tn053/ctd/05301312.cnf
/jgofs/tn053/ctd/05301313.cnf
/jgofs/tn053/ctd/05301314.cnf
/jgofs/tn053/ctd/05301315.cnf
/jgofs/tn053/ctd/05301401.cnf
/jgofs/tn053/ctd/05301402.cnf
/jgofs/tn053/ctd/05301403.cnf
/jgofs/tn053/ctd/05301404.cnf
/jgofs/tn053/ctd/05301405.cnf
/jgofs/tn053/ctd/05301501.cnf
/jgofs/tn053/ctd/05301502.cnf
/jgofs/tn053/ctd/05301503.cnf
/jgofs/tn053/ctd/05301504.cnf
/jgofs/tn053/ctd/05301505.cnf
/jgofs/tn053/ctd/05301506.cnf
/jgofs/tn053/ctd/05301507.cnf
/jgofs/tn053/ctd/05301508.cnf
/jgofs/tn053/ctd/05301509.cnf
/jgofs/tn053/ctd/05301510.cnf
/jgofs/tn053/ctd/05301511.cnf
/jgofs/tn053/ctd/05301512.cnf
/jgofs/tn053/ctd/05301513.cnf
/jgofs/tn053/ctd/05301514.cnf
/jgofs/tn053/ctd/05301515.cnf
/jgofs/tn053/ctd/05301516.cnf
/jgofs/tn053/ctd/05301601.cnf
/jgofs/tn053/ctd/05301602.cnf
/jgofs/tn053/ctd/05301603.cnf
/jgofs/tn053/ctd/05301604.cnf
/jgofs/tn053/ctd/05301701.cnf
/jgofs/tn053/ctd/05301702.cnf
/jgofs/tn053/ctd/05301703.cnf
/jgofs/tn053/ctd/05301801.cnf
/jgofs/tn053/ctd/05301802.cnf
/jgofs/tn053/ctd/05301803.cnf
/jgofs/tn053/ctd/05301804.cnf
/jgofs/tn053/ctd/05301805.cnf
/jgofs/tn053/ctd/05301806.cnf
/jgofs/tn053/ctd/05301807.cnf
/jgofs/tn053/ctd/05301808.cnf
/jgofs/tn053/ctd/05301809.cnf
/jgofs/tn053/ctd/05301810.cnf
/jgofs/tn053/ctd/05301811.cnf
/jgofs/tn053/ctd/05301812.cnf
/jgofs/tn053/ctd/05301813.cnf
/jgofs/tn053/ctd/05301901.cnf
/jgofs/tn053/ctd/05301902.cnf
/jgofs/tn053/ctd/05301903.cnf

MINIMUM DEPTH USED =       0.00000
MAXIMUM DEPTH USED =       500.000 

Sal Correction     = -0.0099729573 + 6.0252734e-06 * Pressure
Standard Deviation =  0.01

MINIMUM DEPTH USED =       500.000
MAXIMUM DEPTH USED =       3022.50

Sal Correction     = -0.005
Standard Deviation =  0.001

Stations 3:

/jgofs/tn053/ctd/05302001.cnf
/jgofs/tn053/ctd/05302002.cnf
/jgofs/tn053/ctd/05302003.cnf
/jgofs/tn053/ctd/05302004.cnf
/jgofs/tn053/ctd/05302005.cnf
/jgofs/tn053/ctd/05302006.cnf
/jgofs/tn053/ctd/05302007.cnf
/jgofs/tn053/ctd/05302008.cnf
/jgofs/tn053/ctd/05302009.cnf
/jgofs/tn053/ctd/05302010.cnf
/jgofs/tn053/ctd/05302011.cnf
/jgofs/tn053/ctd/05302012.cnf
/jgofs/tn053/ctd/05302013.cnf
/jgofs/tn053/ctd/05302014.cnf
/jgofs/tn053/ctd/05302101.cnf
/jgofs/tn053/ctd/05302102.cnf
/jgofs/tn053/ctd/05302103.cnf
/jgofs/tn053/ctd/05302201.cnf
/jgofs/tn053/ctd/05302202.cnf
/jgofs/tn053/ctd/05302203.cnf
/jgofs/tn053/ctd/05302204.cnf
/jgofs/tn053/ctd/05302205.cnf
/jgofs/tn053/ctd/05302206.cnf
/jgofs/tn053/ctd/05302207.cnf
/jgofs/tn053/ctd/05302208.cnf
/jgofs/tn053/ctd/05302209.cnf
/jgofs/tn053/ctd/05302210.cnf
/jgofs/tn053/ctd/05302211.cnf
/jgofs/tn053/ctd/05302212.cnf
/jgofs/tn053/ctd/05302213.cnf
/jgofs/tn053/ctd/05302214.cnf
/jgofs/tn053/ctd/05302301.cnf
/jgofs/tn053/ctd/05302302.cnf
/jgofs/tn053/ctd/05302303.cnf
/jgofs/tn053/ctd/05302304.cnf
/jgofs/tn053/ctd/05302401.cnf
/jgofs/tn053/ctd/05302402.cnf
/jgofs/tn053/ctd/05302403.cnf
/jgofs/tn053/ctd/05302404.cnf
/jgofs/tn053/ctd/05302405.cnf
/jgofs/tn053/ctd/05302406.cnf
/jgofs/tn053/ctd/05302408.cnf
/jgofs/tn053/ctd/05302407.cnf
/jgofs/tn053/ctd/05302501.cnf
/jgofs/tn053/ctd/05302502.cnf
/jgofs/tn053/ctd/05302503.cnf
/jgofs/tn053/ctd/05302504.cnf
/jgofs/tn053/ctd/05302601.cnf
/jgofs/tn053/ctd/05302602.cnf
/jgofs/tn053/ctd/05302603.cnf
/jgofs/tn053/ctd/05302604.cnf
/jgofs/tn053/ctd/05302701.cnf
/jgofs/tn053/ctd/05302801.cnf

MINIMUM DEPTH USED =       0.00000
MAXIMUM DEPTH USED =       500.000 

Sal Correction     = -0.012328868 + 1.4169036e-05 * Pressure
Standard Deviation =  0.01

MINIMUM DEPTH USED =       500.000
MAXIMUM DEPTH USED =       3022.00

Salinity       STDEV=   0.00149842     MEAN=  -0.00682915

Sal Correction     = -.007
Standard Deviation =  .001

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

Therefore in the upper 500 meters, the corrected CTD salinities are good
to at +/- .01 while in the deep water the calibrated CTD salinities
are good to +/- .001.

We expect that the upper layer salinities are better than +/- .01,
but because of the natural variability between in this region, this is
the best that we are able to determine from calibration.