http://lod.bco-dmo.org/id/dataset/2516
eng; USA
utf8
dataset
Highest level of data collection, from a common set of sensors or instrumentation, usually within the same research project
Biological and Chemical Oceanography Data Management Office (BCO-DMO)
Unavailable
508-289-2009
WHOI MS#36
Woods Hole
MA
02543
USA
info@bco-dmo.org
http://www.bco-dmo.org
Monday - Friday 8:00am - 5:00pm
For questions regarding this resource, please contact BCO-DMO via the email address provided.
pointOfContact
2009-10-01
ISO 19115-2 Geographic Information - Metadata - Part 2: Extensions for Imagery and Gridded Data
ISO 19115-2:2009(E)
CTD profile data, including beam attenuation from R/V Thomas G. Thompson TT039, TT043, TT045, TT049, TT050, TT053, TT054 cruises in the Arabian Sea (U.S. JGOFS Arabian Sea project)
2002-06-06
publication
2002-06-06
revision
BCO-DMO Linked Data URI
2002-06-06
creation
http://lod.bco-dmo.org/id/dataset/2516
John M. Morrison
North Carolina State University - Marine, Earth and Atmospheric Sciences
principalInvestigator
Dr Louis A. Codispoti
Old Dominion University
principalInvestigator
Biological and Chemical Oceanography Data Management Office (BCO-DMO)
Unavailable
508-289-2009
WHOI MS#36
Woods Hole
MA
02543
USA
info@bco-dmo.org
http://www.bco-dmo.org
Monday - Friday 8:00am - 5:00pm
For questions regarding this resource, please contact BCO-DMO via the email address provided.
publisher
Cite this dataset as: Morrison, J. M., Codispoti, L. A. (2002) CTD profile data, including beam attenuation from R/V Thomas G. Thompson TT039, TT043, TT045, TT049, TT050, TT053, TT054 cruises in the Arabian Sea (U.S. JGOFS Arabian Sea project). Biological and Chemical Oceanography Data Management Office (BCO-DMO). (Version final) Version Date 2002-06-06 [if applicable, indicate subset used]. http://lod.bco-dmo.org/id/dataset/2516 [access date]
CTD profile data, including beam attenuation Dataset Description: <p>CTD profile data averaged at two decibar intervals, including beam attenuation</p> Methods and Sampling: <p>See Platform deployments for cruise specific documentation</p>
Funding provided by National Science Foundation (NSF) Award Number: unknown Arabian Sea NSF
completed
John M. Morrison
North Carolina State University - Marine, Earth and Atmospheric Sciences
910-962-2304
Center for Marine Science 5600 Marvin K. Moss Lane
Wilmington
NC
28409
USA
morrisonj@uncw.edu
pointOfContact
Dr Louis A. Codispoti
Old Dominion University
804-683-5770
Center for Coastal Physical Oceanography Old Dominion University
Norfolk
VA
23529
USA
codispot@hpl.umces.edu OR lou@ccpo.odu.edu
pointOfContact
asNeeded
Dataset Version: final
Unknown
event
sta
sta_std
cast
date
time
lat
lon
depth
press
temp
cond
sal
potemp
sigma_t
sigma_0
beam_cp
light_bs
fluor
CTD Seabird 911
SeaTech Fluorometer
SeaTech Transmissometer
theme
None, User defined
event
station number
standard station
cast
date
time of day
latitude
longitude
depth
water pressure
water temperature at measurement depth
conductivity
salinity
potential temperature
sigma-t
sigma-theta
beam attenuation
light backscattered
fluorescence
featureType
BCO-DMO Standard Parameters
CTD Sea-Bird 911
Sea Tech Fluorometer
Sea Tech Transmissometer
instrument
BCO-DMO Standard Instruments
TT043
TT045
TT049
TT050
TT053
TT054
TT039
service
Deployment Activity
U.S. JGOFS Arabian Sea
place
Locations
otherRestrictions
otherRestrictions
Access Constraints: none. Use Constraints: Please follow guidelines at: http://www.bco-dmo.org/terms-use Distribution liability: Under no circumstances shall BCO-DMO be liable for any direct, incidental, special, consequential, indirect, or punitive damages that result from the use of, or the inability to use, the materials in this data submission. If you are dissatisfied with any materials in this data submission your sole and exclusive remedy is to discontinue use.
U.S. Joint Global Ocean Flux Study
http://usjgofs.whoi.edu/
U.S. Joint Global Ocean Flux Study
The United States Joint Global Ocean Flux Study was a national component of international JGOFS and an integral part of global climate change research.
The U.S. launched the Joint Global Ocean Flux Study (JGOFS) in the late 1980s to study the ocean carbon cycle. An ambitious goal was set to understand the controls on the concentrations and fluxes of carbon and associated nutrients in the ocean. A new field of ocean biogeochemistry emerged with an emphasis on quality measurements of carbon system parameters and interdisciplinary field studies of the biological, chemical and physical process which control the ocean carbon cycle. As we studied ocean biogeochemistry, we learned that our simple views of carbon uptake and transport were severely limited, and a new "wave" of ocean science was born. U.S. JGOFS has been supported primarily by the U.S. National Science Foundation in collaboration with the National Oceanic and Atmospheric Administration, the National Aeronautics and Space Administration, the Department of Energy and the Office of Naval Research. U.S. JGOFS, ended in 2005 with the conclusion of the Synthesis and Modeling Project (SMP).
U.S. JGOFS
largerWorkCitation
program
U.S. JGOFS Arabian Sea
http://usjgofs.whoi.edu/research/arabian.html
U.S. JGOFS Arabian Sea
<p>The U.S. Arabian Sea Expedition which began in September 1994 and ended in January 1996, had three major components: a U.S. JGOFS Process Study, supported by the National Science Foundation (NSF); Forced Upper Ocean Dynamics, an Office of Naval Research (ONR) initiative; and shipboard and aircraft measurements supported by the National Aeronautics and Space Administration (NASA). The Expedition consisted of 17 cruises aboard the R/V Thomas Thompson, year-long moored deployments of five instrumented surface buoys and five sediment-trap arrays, aircraft overflights and satellite observations. Of the seventeen ship cruises, six were allocated to repeat process survey cruises, four to SeaSoar mapping cruises, six to mooring and benthic work, and a single calibration cruise which was essentially conducted in transit to the Arabian Sea.</p>
Arabian Sea
largerWorkCitation
project
eng; USA
oceans
U.S. JGOFS Arabian Sea
2002-06-06
Arabian Sea
0
BCO-DMO catalogue of parameters from CTD profile data, including beam attenuation from R/V Thomas G. Thompson TT039, TT043, TT045, TT049, TT050, TT053, TT054 cruises in the Arabian Sea (U.S. JGOFS Arabian Sea project)
Biological and Chemical Oceanography Data Management Office (BCO-DMO)
Unavailable
508-289-2009
WHOI MS#36
Woods Hole
MA
02543
USA
info@bco-dmo.org
http://www.bco-dmo.org
Monday - Friday 8:00am - 5:00pm
For questions regarding this resource, please contact BCO-DMO via the email address provided.
pointOfContact
http://lod.bco-dmo.org/id/dataset-parameter/9651.rdf
Name: event
Units: dimensionless
Description: <p>a unique number assigned to each sampling<br />
operation consisting of month MM, day DD, hour HH and minute mm</p>
http://lod.bco-dmo.org/id/dataset-parameter/9652.rdf
Name: sta
Units: dimensionless
Description: <p>station number</p>
http://lod.bco-dmo.org/id/dataset-parameter/9653.rdf
Name: sta_std
Units: dimensionless
Description: <p>Arabian Sea standard station identifier</p>
http://lod.bco-dmo.org/id/dataset-parameter/9654.rdf
Name: cast
Units: dimensionless
Description: <p>CTD cast number</p>
http://lod.bco-dmo.org/id/dataset-parameter/9655.rdf
Name: date
Units: unknown
Description: <p>date (YYYYMMDD) decoded as follows<br />
YYYY = year, MM = month, DD = day Date converted to UTC(GMT).</p>
http://lod.bco-dmo.org/id/dataset-parameter/9656.rdf
Name: time
Units: decimal hours
Description: <p>time of day in UTC(GMT)</p>
http://lod.bco-dmo.org/id/dataset-parameter/9657.rdf
Name: lat
Units: decimal degrees
Description: <p>latitude of cast, negative = south</p>
http://lod.bco-dmo.org/id/dataset-parameter/9658.rdf
Name: lon
Units: decimal degrees
Description: <p>longitude of cast, negative = west</p>
http://lod.bco-dmo.org/id/dataset-parameter/9659.rdf
Name: depth
Units: meters
Description: <p>sample depth reported as meters</p>
http://lod.bco-dmo.org/id/dataset-parameter/9660.rdf
Name: press
Units: decibars
Description: <p>sample depth reported as pressure</p>
http://lod.bco-dmo.org/id/dataset-parameter/9661.rdf
Name: temp
Units: degrees C
Description: <p>temperature, IPTS-68</p>
http://lod.bco-dmo.org/id/dataset-parameter/9662.rdf
Name: cond
Units: milliSiemens/centimeter
Description: <p>conductivity</p>
http://lod.bco-dmo.org/id/dataset-parameter/9663.rdf
Name: sal
Units: dimensionless
Description: <p>salinity, PSS-78</p>
http://lod.bco-dmo.org/id/dataset-parameter/9664.rdf
Name: potemp
Units: degrees C
Description: <p>potential temperature, IPTS-68</p>
http://lod.bco-dmo.org/id/dataset-parameter/9665.rdf
Name: sigma_t
Units: kilogram/meter^3
Description: <p>sigma-t</p>
http://lod.bco-dmo.org/id/dataset-parameter/9666.rdf
Name: sigma_0
Units: kilogram/meter^3
Description: <p>sigma theta (potental density)</p>
http://lod.bco-dmo.org/id/dataset-parameter/9667.rdf
Name: beam_cp
Units: 1/meter
Description: <p>beam attenuation due to particles</p>
http://lod.bco-dmo.org/id/dataset-parameter/9668.rdf
Name: light_bs
Units: volts
Description: <p>backscattered light from a Light Scattering Sensor</p>
http://lod.bco-dmo.org/id/dataset-parameter/9669.rdf
Name: fluor
Units: milligram/meter^3
Description: <p>relative fluorescence, corrected by Seabird software to chlorophyll-a</p>
GB/NERC/BODC > British Oceanographic Data Centre, Natural Environment Research Council, United Kingdom
Biological and Chemical Oceanography Data Management Office (BCO-DMO)
Unavailable
508-289-2009
WHOI MS#36
Woods Hole
MA
02543
USA
info@bco-dmo.org
http://www.bco-dmo.org
Monday - Friday 8:00am - 5:00pm
For questions regarding this resource, please contact BCO-DMO via the email address provided.
pointOfContact
5481302
https://datadocs.bco-dmo.org/file/A8lwJ30FV3ozJl/ctd_TT039.csv
ctd_TT039.csv
version October 31, 1995
John Morrison
CTD data
Thomas Thompson cruise TN039
Please see documentation for ctd set up and calibration
download
5696316
https://datadocs.bco-dmo.org/file/ypy01jDTAEW2jl/ctd_TT043.csv
ctd_TT043.csv
version November 5, 1996
John Morrison
CTD data
Thomas Thompson cruise TTN-043 to the Arabian Sea
Current version includes updates by Wilford Gardner adding:
beam_cp, light_bs, fluor
download
6169336
https://datadocs.bco-dmo.org/file/XYl1jWRfMYnZ0g/ctd_TT045.csv
ctd_TT045.csv
version November 7, 1996
John Morrison
CTD data
Thomas Thompson cruise TTN-045 to the Arabian Sea
Current version includes updates by Wilford Gardner adding:
beam_cp, light_bs, fluor
download
5864172
https://datadocs.bco-dmo.org/file/k6LyJ1PHqvME2N/ctd_TT049.csv
ctd_TT049.csv
version November 18, 1996
John Morrison
CTD data
Thomas Thompson Cruise TTN-049, Arabian Sea, Process Cruise 4
Current version includes updates by Wilford Gardner adding:
beam_cp, light_bs, fluor
download
6324717
https://datadocs.bco-dmo.org/file/VJjY8R9S2j6y2x/ctd_TT050.csv
ctd_TT050.csv
version April 3, 1998
John Morrison
CTD measurements
Thomas Thompson Cruise TTN-050, Process Cruise 5, Arabian Sea
Current version includes updates by Wilford Gardner adding:
beam_cp, light_bs, fluor
download
4670495
https://datadocs.bco-dmo.org/file/ypy01jnULWy78Z/ctd_TT053.csv
ctd_TT053.csv
version September 25, 1996
John Morrison
CTD core measurements
Thomas Thompson Cruise TTN-053, Process Cruise 6 to the Arabian Sea
download
8428677
https://datadocs.bco-dmo.org/file/2GN3nMQu689px3/ctd_TT054.csv
ctd_TT054.csv
version June 6, 2002
(original version January 31, 1997)
John Morrison
CTD core measurements
Thomas Thompson Cruise TTN-054, Process Cruise 7 to the Arabian Sea
Current version includes updates by Wilford Gardner adding:
beam_cp, light_bs and fluor
download
https://osprey.bco-dmo.org/dataset/2516/data/download
download
onLine
dataset
<p>See Platform deployments for cruise specific documentation</p>
from Cruise: TT043 <pre>
<b>PI:</b> John Morrison
<b>of:</b> North Carolina State University
<b>PI on Optics:</b> Wilford Gardner, Mary Jo Richardson
<b>dataset:</b> CTD profile data averaged at two decibar intervals,
including beam attenuation
<b> dates: </b> January 08, 1995 to February 01, 1995
<b> location:</b> N: 22.4830 S: 9.9826 W: 57.2999 E: 68.7500
<b>project/cruise:</b> Arabian Sea/TTN-043 - Process Cruise 1 (Late NE Monsoon)
<b>ship:</b> Thomas Thompson
<pre>
John M. Morrison -- 15 December 1995
TN043: U.S. JGOFS Arabian Sea Process Study -- Process Cruise #1:
<hr>
This "readme" file pertains to the CTD data taken during RV T.G. Thompson
cruise TN043. This cruise was the first JGOFS Arabian Sea Process Leg and
took place between 8 January and 5 February 1995. Dr. M. Roman of the
University of Maryland's Horn Point Laboratory was the chief scientist.
A number of CTD casts were made in test mode. The data from these casts
were deemed unrecoverable (noisy data due to winch problems) and are listed
as follows:
event 01220023 station 17 cast 11
event 01290934 station 27 cast 05
event 01312228 station 29 cast 03
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
CTD Calibration:
On this cruise, two different CTD configurations were used. The processing
and calibration information for each of the configurations are given below:
configuration 1
-------------------------------
John M. Morrison 15 December 1995
Setup, processing and calibation information for the initial setup of the
CTD for cruise TN043. It was used for the following casts:
cruise 043 station 001 cast 01
cruise 043 station 002 cast 01
cruise 043 station 003 cast 01
cruise 043 station 003 cast 03
cruise 043 station 004 cast 01
cruise 043 station 004 cast 04
cruise 043 station 005 cast 01
cruise 043 station 006 cast 01
cruise 043 station 006 cast 03
cruise 043 station 007 cast 01
cruise 043 station 007 cast 05
Sea-Bird Processing Information: (Example from ctd cast 04300201)
* Sea-Bird SBE 9 Raw Data File:
* FileName = G:�4300201.DAT
* Software Version 4.205
* Temperature SN = 1605
* Conductivity SN = 1371
* Number of Bytes Per Scan = 37
* Number of Voltage Words = 4
* System UpLoad Time = Jan 09 1995 02:08:20
* NMEA Latitude = 22 28.96 N
* NMEA Longitude = 061 11.08 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 Arabian Sea Expedition
# nquan = 15
# nvalues = 508
# 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 = depS: depth, salt water [m]
# name 9 = potemp068: potential temperature, pri, IPTS-68 [deg C]
# name 10 = sigma-t00: density, sigma-t [kg/m^3], T0, C0
# name 11 = sigma-i00: density, sigma-theta [kg/m^3], T0, C0
# name 12 = sal00: salinity, PSS-78 [PSU], T0, C0
# name 13 = sal11: salinity, PSS-78 [PSU], T1, C1
# name 14 = flag: 0.000e+00
# span 0 = 16.4013, 24.5890
# span 1 = 45.821327, 54.931889
# span 2 = 1.000, 256.000
# span 3 = 16.4010, 24.5959
# span 4 = 45.815933, 54.939217
# span 5 = -0.28523, 10.73771
# span 6 = 28.99, 91.08
# span 7 = 0.000e+00, 0.000e+00
# span 8 = 0.994, 254.240
# span 9 = 16.3613, 24.5776
# span 10 = 24.6830, 26.6361
# span 11 = 24.6838, 26.6459
# span 12 = 36.1022, 36.7169
# span 13 = 36.0998, 36.7173
# span 14 = 0.000e+00, 0.000e+00
# interval = decibars: 1
# start_time = Jan 09 1995 02:08:20
# bad_flag = -9.990e-29
# serial_numbers = t0:1605, c0:1371, pr:34901, t1:1316, c1:1084, ox:352,
upoly0:AC3, upoly1:AC3, stLs60D
# datcnv_date = Jan 09 1995 03:40:04, 4.205
# datcnv_in = 04300201.DAT CTD_24.CON 1605 1371 34901
# datcnv_skipover = 0
# wildedit_date = Jan 09 1995 03:42:01, 4.205
# wildedit_in = 04300201.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
# wildedit_excl_bad_scans = yes
# celltm_date = Jan 09 1995 03:42:45, 4.205
# celltm_in = TEMP.CNV
# celltm_alpha = 0.0300, 0.0000
# celltm_tau = 9.0000, 0.0000
# filter_date = Jan 09 1995 03:43:22, 4.205
# filter_in = 04300201.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 = Jan 09 1995 03:44:38, 4.205
# loopedit_in = TEMP.CNV
# loopedit_minVelocity = 0.000
# loopedit_excl_bad_scans = yes
# binavg_date = Jan 09 1995 03:45:30, 4.205
# binavg_in = 04300201.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 = Jan 09 1995 03:46:09, 4.205
# derive_in = TEMP.CNV CTD_24.CON
# file_type = ascii
*END*
Calibration:
Calibration for Conductivity and Salinity:
MINIMUM DEPTH USED = 500.000
Conductivity STDEV= 0.00259877 MEAN= 0.00169401
Salinity STDEV= 0.00266719 MEAN= 0.00180285
If full range was used for the Conductivity and Salinity Calibration, the
mean remains the same, but the STDEV becomes larger as would be expected in
the high-gradient, and variable surface layers.
Therefore, a correction of -.002 was applied to the shipboard Conductivities
and Salinities.
The reported Conductivities and Salinities are good to +/- .003.
configuration 2
----------------------------------
John M. Morrison 15 December 1995
Setup, processing and calibation information for the second setup of the
CTD for cruise TN043. It was used for the following casts:
cruise 043 station 007 cast 11
cruise 043 station 007 cast 13
cruise 043 station 007 cast 14
cruise 043 station 008 cast 01
cruise 043 station 008 cast 03
cruise 043 station 009 cast 01
cruise 043 station 009 cast 03
cruise 043 station 010 cast 01
cruise 043 station 010 cast 03
cruise 043 station 011 cast 01
cruise 043 station 011 cast 04
cruise 043 station 012 cast 01
cruise 043 station 012 cast 03
cruise 043 station 013 cast 01
cruise 043 station 013 cast 07
cruise 043 station 013 cast 09
cruise 043 station 013 cast 10
cruise 043 station 013 cast 11
cruise 043 station 014 cast 01
cruise 043 station 014 cast 03
cruise 043 station 015 cast 01
cruise 043 station 015 cast 03
cruise 043 station 016 cast 01
cruise 043 station 016 cast 03
cruise 043 station 017 cast 01
cruise 043 station 017 cast 05
cruise 043 station 017 cast 09
cruise 043 station 017 cast 10
cruise 043 station 017 cast 11
cruise 043 station 018 cast 01
cruise 043 station 018 cast 03
cruise 043 station 019 cast 02
cruise 043 station 019 cast 03
cruise 043 station 020 cast 01
cruise 043 station 020 cast 02
cruise 043 station 021 cast 01
cruise 043 station 021 cast 05
cruise 043 station 021 cast 08
cruise 043 station 021 cast 10
cruise 043 station 021 cast 12
cruise 043 station 021 cast 13
cruise 043 station 022 cast 01
cruise 043 station 023 cast 01
cruise 043 station 024 cast 01
cruise 043 station 024 cast 03
cruise 043 station 025 cast 01
cruise 043 station 025 cast 03
cruise 043 station 026 cast 01
cruise 043 station 026 cast 05
cruise 043 station 026 cast 08
cruise 043 station 026 cast 10
cruise 043 station 026 cast 12
cruise 043 station 027 cast 01
cruise 043 station 027 cast 02
cruise 043 station 027 cast 05
cruise 043 station 028 cast 01
cruise 043 station 028 cast 05
cruise 043 station 028 cast 09
cruise 043 station 028 cast 10
cruise 043 station 028 cast 11
cruise 043 station 029 cast 01
cruise 043 station 029 cast 02
cruise 043 station 029 cast 03
cruise 043 station 030 cast 01
Sea-Bird Processing Information: (Example from ctd cast 04300713)
* Sea-Bird SBE 9 Raw Data File:
* FileName = G:�4300713.DAT
* Software Version 4.205
* Temperature SN = 1605
* Conductivity SN = 1371
* Number of Bytes Per Scan = 37
* Number of Voltage Words = 4
* System UpLoad Time = Jan 13 1995 09:20:09
* NMEA Latitude = 19 9.98 N
* NMEA Longitude = 067 9.97 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 Arabian Sea Expedition
# nquan = 15
# nvalues = 5061
# 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 = depS: depth, salt water [m]
# name 9 = potemp068: potential temperature, pri, IPTS-68 [deg C]
# name 10 = sigma-t00: density, sigma-t [kg/m^3], T0, C0
# name 11 = sigma-i00: density, sigma-theta [kg/m^3], T0, C0
# name 12 = sal00: salinity, PSS-78 [PSU], T0, C0
# name 13 = sal11: salinity, PSS-78 [PSU], T1, C1
# name 14 = flag: 0.000e+00
# span 0 = 2.1813, 24.9021
# span 1 = 31.823267, 55.041656
# span 2 = 1.000, 2532.000
# span 3 = 2.1820, 24.9060
# span 4 = 31.821650, 55.043922
# span 5 = -1.72205, 3.64451
# span 6 = 89.83, 93.30
# span 7 = 2.202e-01, 1.966e+00
# span 8 = 0.994, 2501.573
# span 9 = 1.9943, 24.9015
# span 10 = 24.5439, 27.7705
# span 11 = 24.5441, 27.7856
# span 12 = 34.7668, 36.5490
# span 13 = 34.7638, 36.5478
# span 14 = 0.000e+00, 0.000e+00
# interval = decibars: 1
# start_time = Jan 13 1995 09:20:09
# bad_flag = -9.990e-29
# serial_numbers = t0:1605, c0:1371, pr:57657, t1:1316, c1:1084, ox:132,
stLs6000:239, xmiss:173D, flS:D
# datcnv_date = Jan 13 1995 11:19:52, 4.205
# datcnv_in = 04300713.DAT CTD_24.CON 1605 1371 57657
# datcnv_skipover = 0
# wildedit_date = Jan 13 1995 11:27:22, 4.205
# wildedit_in = 04300713.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
# wildedit_excl_bad_scans = yes
# celltm_date = Jan 13 1995 11:30:04, 4.205
# celltm_in = TEMP.CNV
# celltm_alpha = 0.0300, 0.0000
# celltm_tau = 9.0000, 0.0000
# filter_date = Jan 13 1995 11:32:20, 4.205
# filter_in = 04300713.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 = Jan 13 1995 11:37:05, 4.205
# loopedit_in = TEMP.CNV
# loopedit_minVelocity = 0.000
# loopedit_excl_bad_scans = yes
# binavg_date = Jan 13 1995 11:40:25, 4.205
# binavg_in = 04300713.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 = Jan 13 1995 11:42:59, 4.205
# derive_in = TEMP.CNV CTD_24.CON
# file_type = ascii
*END*
Calibration:
Calibration for Conductivity and Salinity:
MINIMUM DEPTH USED = 500.000
Conductivity STDEV= 0.00258307 MEAN= -0.00156166
Salinity STDEV= 0.00273680 MEAN= -0.00164091
If full range was used for the Conductivity and Salinity Calibration, the
mean remains the same, but the STDEV becomes larger as would be expected in
the high-gradient, and variable surface layers.
Therefore, a correction of +.002 was applied to the shipboard Conductivities
and Salinities.
The reported Conductivities and Salinities are good to +/- .003.
</pre>
from Cruise: TT045 <pre>
<strong>PI:</strong> John Morrison
<strong>of:</strong> North Carolina State University
<strong>PI on Optics:</strong> Wilford Gardner, Mary Jo Richardson
<strong>dataset:</strong> CTD profile data at two decibar intervals, including
beam attenuation
<strong>dates:</strong> March 14, 1995 to April 08, 1995
<strong>location:</strong> N: 22.4858 S: 9.9993 W: 57.3007 E: 68.7532
<strong>project/cruise:</strong> Arabian Sea/TTN-045 - Process Cruise 2 (Spring Intermonsoon)
<strong>ship:</strong> Thomas Thompson
</pre>
<pre>
John M. Morrison -- 20 December 1995
TN045: JGOFS Arabian Sea Process Study -- Process Cruise #2:
This "readme" file pertains to the CTD data taken
during RV T.G. Thompson cruise TN045. This cruise was the
second JGOFS Arabian Sea Process Leg and took place during March-April
1995. Dr. John Marra of the Lamont Doherty Earth Observatory
was the chief scientist.
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
CTD Calibration:
On this cruise, one CTD configuration was used. The processing
and calibration information for this configuration is given below:
This the setup, processing and calibation information for the
setup of all the CTD casts for cruise TN045.
Sea-Bird Processing Information: Example from /jgofs/tn045/ctd/0400101.cnv
* Sea-Bird SBE 9 Raw Data File:
* FileName = G:</pre>
from Cruise: TT049 <pre>
<b>PI:</b> John Morrison
<b>of:</b> North Carolina State University
<b>PI on Optics:</b> Wilford Gardner, Mary Jo Richardson
<b>dataset:</b> CTD profile data averaged at two decibar intervals, including beam attenuation
<b>dates:</b> July 18, 1995 to August 13, 1995
<b>location:</b> N: 22.5268 S: 9.911 W: 57.2997 E: 68.7507
<b>project/cruise:</b> Arabian Sea/TTN-049 - Process Cruise 4 (Middle SW Monsoon)
<b>ship:</b> Thomas Thompson
</pre>
<pre>
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:
from Cruise: TT050 <pre>
<b>PI:</b> John Morrison
<b>of:</b> North Carolina State University
<b>PI on Optics:</b> Wilford Gardner, Mary Jo Richardson
<b>dataset:</b> CTD profile data averaged at two decibar intervals,
including beam attenuation
<b>dates:</b> August 18, 1995 to September 13, 1995
<b>location:</b> N: 22.4998 S: 9.9125 W: 57.3004 E: 68.7527
<b>project/cruise:</b> Arabian Sea/TTN-050 - Process Cruise 5 (Late SW Monsoon)
<b>ship:</b> Thomas Thompson
</pre>
<pre>
John M. Morrison -- 8 July 1996
TN050: JGOFS Arabian Sea Process Study -- Process Cruise #5
This "readme" file pertains to the CTD data taken
during RV T.G. Thompson cruise TN050. This cruise was the
fifth JGOFS Arabian Sea Process Leg and took place during August -
September 1995. Prof. Sharon L. Smith of the University of Miami
(ssmith@rsmas.miami.edu) was the chief scientist.
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.
CTD Calibration:
On this cruise, one CTD configurations was used. The processing
and calibration information for this configuration is given as follows:
John M. Morrison 28 May 1996
This is the setup, processing and calibation information for
the CTD for cruise TN050.
Both the primary and secondary set of CTD sensors were calibrated
for this cruise. The calibrated data from the primary set of sensors
are used for the final data files, except for 4 stations where the
primary CTD sensors malfunctioned. This malfunction appeared to be
to a failure of the pump or something being trapped in the conductivity
cell of the primary sensor.
In addition, in both the primary and secondary sensors,
there was a trend in the differences between the CTD and
bottle salinities in the upper 500 meters of the data. Therefore,
the upper 500 meters were calibrated separately from the data below
500 meters.
Finally, a filter of +/-0.01 was applied to the differences between
CTD and Bottle salinities to remove large differences associated with
the salinity gradient region of the water column and not associated
with the calibration of the CTD sensors.
Both calibrations are given below, as well as a listing of stations
for which each calibration was used.
_________________________________________________________________________
Sea-Bird Processing Information: Example from 05000101.cnv
* Sea-Bird SBE 9 Raw Data File:
* FileName = G:
from Cruise: TT053 <pre>
<b>PI:</b> John Morrison
<b>of:</b> North Carolina State University
<b>dataset:</b> CTD profile data averaged at two decibar intervals
<b>dates:</b> October 29, 1995 to November 25, 1995
<b>location:</b> N: 24.3329 S: 10.0823 W: 56.4858 E: 67.1784
<b>project/cruise:</b> Arabian Sea/TTN-053 - Process Cruise 6 (bio-optics)
<b>ship:</b> Thomas Thompson
</pre>
<pre>
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:
from Cruise: TT054 <pre>
<b>PI:</b> John Morrison
<b>of:</b> North Carolina State University
<b>PI on Optics:</b> Wilford Gardner, Mary Jo Richardson
<b>dataset:</b> CTD profile data averaged at two decibar intervals,
including beam attenuation
<b>dates:</b> November 30, 1995 to December 26, 1995
<b>location:</b> N: 22.5171 S: 9.9673 W: 57.2992 E: 68.7849
<b>project/cruise:</b> Arabian Sea/TTN-054 - Process Cruise 7 (Early NE Monsoon)
<b>ship:</b> Thomas Thompson
</pre>
<pre>
John M. Morrison -- 18 July 1996
TN054: JGOFS Arabian Sea Process Study -- Process Cruise #7:
This "readme" file pertains to the CTD data taken
during RV T.G. Thompson cruise TN054. This cruise was the
seventh JGOFS Arabian Sea Process Leg and took place during November -
December 1995. Wilford Gardner of Texas A&M University
(wgardner@astra.tamu.edu) was the chief scientist.
Dissolved oxygen, ransmissometer 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
CTD Calibration:
On this cruise, one CTD configurations was used. The processing
and calibration information for this configuration are given
below:
John M. Morrison -- 25 June 1996
This the setup, processing and calibation information for
the CTD for cruise TN054.
Sea-Bird Processing Information: Example from 05400101.cnv
* Sea-Bird SBE 9 Raw Data File:
* FileName = G:
from Cruise: TT039 <pre>
<b>PI:</b> John Morrison
<b>dataset:</b> CTD profile data at one decibar intervals
<b>project/cruise:</b> Arabian Sea/TTN039 - Intercalibration Cruise
<b>ship:</b> Thomas Thompson
John M. Morrison 15 August 1995
TN039 -- JGOFS Arabian Sea Process Training and Calibration Cruise:
General Comments:
This "readme" file pertains to the CTD data collected during RV T.G.
Thompson cruise TN039. This cruise took advantage of the sampling
and training opportunities provided by the Thompson's transit leg
from Singapore to Oman. The purposes of this cruise included:
1) testing equipment and methods that would be used on the subsequent
JGOFS Arabian Sea process cruises,
2) finalizing the hydrographic and data-processing protocols that would be
used on subsequent JGOFS Arabian Sea process cruises,
3) training participants from Pakistan and Oman,
4) collecting as much data as possible to extend the temporal and spatial
coverage of the time-series observations included in the JGOFS Arabian
Sea process study.
The stations from which the data was deemed unrecoverable are listed as
follows:
stations deleted
cruise tn039 sta 4 cast 1
cruise tn039 sta 6 cast 1
cruise tn039 sta 6 cast 2
stations truncated
Deleted data below 1000 db, sta 21 cast 2
Deleted data below 3000 db, sta 21 cast 3
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
CTD Calibration:
On this cruise, three different CTD configurations were used. The processing
and calibration information for each of the configurations are given below:
</pre>
<ul>
<li><a href="http://dataone.whoi.edu/PI-NOTES/arabian/Morrison-ctd1.039">Setup, processing and calibration information for the Primary
setup for cruise TN039</a>
<li><a href="http://dataone.whoi.edu/PI-NOTES/arabian/Morrison-ctd2a.039">Setup, processing and calibration information for the Secondary (a) setup for cruise TN039</a>
<li><a href="http://dataone.whoi.edu/PI-NOTES/arabian/Morrison-ctd2b.039">Setup, processing and calibration information for the Secondary (b) setup for cruise TN039</a>
</ul>
Specified by the Principal Investigator(s)
<p>Beam Attenuation Coefficient, Light Scattering, Fluorescence protocols</p>
<p>&nbsp;</p>
<h6>Wilford Gardner, Jan Gundersen, Mary Jo Richardson.<br />
Texas A&amp;M University</h6>
<p>&nbsp;</p>
<pre>
<strong>Data Reduction Scheme</strong>
The primary purpose for measuring the beam attenuation
in JGOFS programs is to determine the concentration and distribution of
particulate matter (PM) or particulate organic carbon (POC) in the
water with continuous profiling rather than with limited discrete
samples. Towards this end, a 25 cm Sea Tech Transmissometer was
interfaced with the University of Washington's SeaBird CTD for all
Arabian Sea cruises. Transmissometer data were analyzed for the five
process cruises (TN043, TN045, TN049, TN050 and TN054) that occupied a
standard set of stations. Data from the raw CTD files were binned at 2
db intervals through SeaBird's SEASOFT program, which has a spike
removal subroutine which we have tested and found to remove
transmissometer data spikes properly. The data were corrected for
factory and field air calibrations. Beam transmission was converted to
beam attenuation coefficients using c=-(1/r)*ln(%Tr/100) where c=beam
attenuation coefficient (m^-1), r=beam path length (m), and Tr=% beam
transmission.
The Arabian Sea data set presented some challenges because 1-4
different transmissometers were used on any given cruise, complicating
the data calibration. It is impractical to do a proper bench or air
calibration prior for each CTD cast since the deck of the ship is not
always a clean environment and atmospheric conditions can change
rapidly and affect the air readings. One calibration method is to
compare the beam attenuation at depth where the particle concentration
is relatively invariant. The primary concern is ensuring that the
optical windows are uniformly clean, which is best determined by
comparing adjacent profiles. Unfortunately, many of the CTD casts
extended only to 150 m or less, which was usually shallower than the
particle minimum. Furthermore, the stations covered a wide geographic
area, so it is more likely that the particle minimum at depth could
vary. The primary method for comparing the beam attenuation signal to
particulate matter (PM) concentration or particulate organic carbon
(POC) concentration is to filter water samples and determine the dry
weight using stable filters (0.4 um pore size Poretics filters in this
case), or the amount of organic carbon on a glass fiber filter (0.7 um
nominal pore size). The beam c data for those bottle depths (chosen as
the cp value of the 2 db bin within which the sample depth fell) are
then regressed against PM or POC using a Model II regression to
determine the intercept where the concentration of particles in the
water equals zero. Theoretically this value should be 0.364 since the
transmissometers are set at the factory to read 0.364 in particle-free
water. PM was filtered on four of the five cruises where beam c was
analyzed. POC was measured on the one cruise for which no PM
measurements were made (TN049) as well as most of the other cruises.
In order to determine the attenuation specific to particulate matter,
the attenuation due to water must be subtracted from the beam c values
( cp = c - cw). Practically, cw is determined as the minimum
attenuation measured during each cruise. It must be noted that this
minimum attenuation value is the "cleanest" water observed and is not
particle free. Thus, the regressions of the cp data versus particle
concentrations must be adjusted.
A prediction of the PM concentration can be obtained from the
resulting equations for each cruise:
TN043 -&gt; PM = 602 * cp (r^2 = 0.86)
TN045 -&gt; PM = 483 * cp (r^2 = 0.87)
TN050 -&gt; PM = 687 * cp (r^2 = 0.92)
TN054 -&gt; PM = 615 * cp (r^2 = 0.86)
PM is in ug/Kg, and cp is attenuation per meter.
Note that these are Model II regressions so the equations are the same
if PM is regressed versus cp or vice versa. For comparison,
the relationships between particle concentration and attenuation in
surface waters of previous JGOFS programs were:
PM = 1022*cp North Atlantic Bloom Exp.
PM = 451*cp EqPac Spring Time Series
PM = 647*cp EqPac Fall Time Series
<strong>Chlorophyll</strong>
Chlorophyll-a fluorescence distribution in the Arabian Sea was
determined, in-situ, with a SeaTech Fluorometer. The fluorometer was
interfaced with the Sea-Bird CTD, and the data were acquired in the
same format as the transmissometer data. The Fluorometer is a standard
irradiation/emission system. When chlorophyll a is excited by blue
light (425 nm), it will fluoresce at a peak wavelength of 685 nm (red
light). The emission detector is filtered to a peak response in order
to make the measurement insensitive to the excitation source. The
amount of fluoresced light detected is converted to a voltage range of
0 to 5 volts. A signal gain of 10x was used, setting sensitivity to
3mg chl-a m^-3. The fluorometer is set to sample with a three second time
constant to smooth the data. A baffle has been placed in front of the
emission detector in an attempt to make it insensitive to ambient light
(SeaTech Fluorometer Manual). The SEASOFT software converts the
measured voltage into a relative chlorophyll-a value using the
equation:
[volts * signal gain/5] + offset = mg chl-a m^-3
These relative values were calibrated using discreet
chlorophyll samples (taken by various JGOFS scientists and analyzed
onboard the ship using a Turner Fluorometer). There is a good (r^2 =
0.90) linear correlation between fluorometer-determined chlorophyll-a
fluorescence, and the chlorophyll-a concentrations determined using a
Turner fluorometer. Regressions were made for each cruise individually,
but the correlations (based on the standard deviation of the slope and
intercept) were improved when data from cruises TN049, TN050, and TN054
were combined. Prior to TN049, chlorophyll samples were taken from the
Trace-Metal rosette, which contained no CTD or fluorometer for accurate
depth or fluorescence measurements. We attempted a comparison between
standard CTD/fluorometer profiles made close in time to the Trace-Metal
casts on which chlorophyll measurements were made, but the lack of
accurate depths or water density for the discreet samples plus the
temporal variability between casts introduced too much scatter for a
useful correlation. There were too few chlorophyll a measurements made
on the standard CTD casts during TN043 and TN045 to independently
calibrate the fluorometer. This added to the appeal of a general
calibration for the fluorescence signal for all cruises, though we
recognize that data for two cruises were not included. We emphasize
for future work that it is necessary to have a fluorometer and CTD on
the rosette at the time chlorophyll samples are being taken in order to
accurately calibrate the fluorescence signal. Furthermore continuous
profiles from a fluorometer provide higher resolution than discreet
samples alone.
Slightly different slopes and intercepts were observed in the
fluorescence/chlorophyll correlations for samples above and below the
chlorophyll maximum. Therefore the depth of the chlorophyll maximum was
determined by visual inspection of each profile (to avoid confusion
with individual spikes) and the samples were divided into two
categories, separated at a depth 10 m beneath the maximum fluorescence
value. The assumption (substantiated by inspection of the data) is that
chlorophyll-containing particles within the subsurface chlorophyll
maximum are more similar to those above the maximum than below. A model
II linear regression on each group of data indicated a very slight
difference in slopes between the two groups, but a substantial offset
in the intercepts. This results in a difference in the concentration of
predicted chlorophyll based on the fluorescence above and below the
chlorophyll maximum. Similar differences in chlorophyll fluorescence
above and below the chlorophyll maximum were noticed by Pak et
al.(1988). Equations are provided here for both regions in the Arabian Sea.
Above the depth of the chlorophyll maximum:
Chl a = 0.357*Fl + 0.078 (r^2 = 0.86)
Below the depth of the chlorophyll maximum:
Chl a = 0.389*Fl - 0.05 (r^2 = 0.93)
<strong>LSS - SeaTech Light Scattering Sensor</strong>
Light scattering due to particles was monitored using a SeaTech
Light Scattering Sensor (LSS). The LSS projects light from two 880 nm
(infrared) LEDs into a sampling volume that varies depending upon the
concentration of particulate matter, but that is roughly the shape of a
stretched balloon. Back-scattered light from the particulate matter is
measured by a detector. The range on the LSS was set to 0 - 33 mg/l.
The amount of light detected is scaled to a 0-5 volt output, but in the
Arabian Sea most values were less than 0.5 volts. The LSS output
depends upon the nature of the particulate matter and will vary with
changes in particle size distribution, shape, index of refraction,
organic/inorganic content etc. Therefore the LSS requires site-specific
calibration. The LSS was interfaced with the SeaBird CTD and the data
were handled in the same format as the transmissometer and fluorometer
data.
</pre>
from Cruise: TT043 <pre>
<h2>Beam Attenuation Coefficient, Light Scattering, Fluorescence protocols
Wilford Gardner, Jan Gundersen, Mary Jo Richardson.
Texas A&M University</h2>
<b>Data Reduction Scheme</b>
The primary purpose for measuring the beam attenuation
in JGOFS programs is to determine the concentration and distribution of
particulate matter (PM) or particulate organic carbon (POC) in the
water with continuous profiling rather than with limited discrete
samples. Towards this end, a 25 cm Sea Tech Transmissometer was
interfaced with the University of Washington's SeaBird CTD for all
Arabian Sea cruises. Transmissometer data were analyzed for the five
process cruises (TN043, TN045, TN049, TN050 and TN054) that occupied a
standard set of stations. Data from the raw CTD files were binned at 2
db intervals through SeaBird's SEASOFT program, which has a spike
removal subroutine which we have tested and found to remove
transmissometer data spikes properly. The data were corrected for
factory and field air calibrations. Beam transmission was converted to
beam attenuation coefficients using c=-(1/r)*ln(%Tr/100) where c=beam
attenuation coefficient (m^-1), r=beam path length (m), and Tr=% beam
transmission.
The Arabian Sea data set presented some challenges because 1-4
different transmissometers were used on any given cruise, complicating
the data calibration. It is impractical to do a proper bench or air
calibration prior for each CTD cast since the deck of the ship is not
always a clean environment and atmospheric conditions can change
rapidly and affect the air readings. One calibration method is to
compare the beam attenuation at depth where the particle concentration
is relatively invariant. The primary concern is ensuring that the
optical windows are uniformly clean, which is best determined by
comparing adjacent profiles. Unfortunately, many of the CTD casts
extended only to 150 m or less, which was usually shallower than the
particle minimum. Furthermore, the stations covered a wide geographic
area, so it is more likely that the particle minimum at depth could
vary. The primary method for comparing the beam attenuation signal to
particulate matter (PM) concentration or particulate organic carbon
(POC) concentration is to filter water samples and determine the dry
weight using stable filters (0.4 um pore size Poretics filters in this
case), or the amount of organic carbon on a glass fiber filter (0.7 um
nominal pore size). The beam c data for those bottle depths (chosen as
the cp value of the 2 db bin within which the sample depth fell) are
then regressed against PM or POC using a Model II regression to
determine the intercept where the concentration of particles in the
water equals zero. Theoretically this value should be 0.364 since the
transmissometers are set at the factory to read 0.364 in particle-free
water. PM was filtered on four of the five cruises where beam c was
analyzed. POC was measured on the one cruise for which no PM
measurements were made (TN049) as well as most of the other cruises.
In order to determine the attenuation specific to particulate matter,
the attenuation due to water must be subtracted from the beam c values
( cp = c - cw). Practically, cw is determined as the minimum
attenuation measured during each cruise. It must be noted that this
minimum attenuation value is the "cleanest" water observed and is not
particle free. Thus, the regressions of the cp data versus particle
concentrations must be adjusted.
A prediction of the PM concentration can be obtained from the
resulting equations for each cruise:
TN043 -> PM = 602 * cp (r^2 = 0.86)
TN045 -> PM = 483 * cp (r^2 = 0.87)
TN050 -> PM = 687 * cp (r^2 = 0.92)
TN054 -> PM = 615 * cp (r^2 = 0.86)
PM is in ug/Kg, and cp is attenuation per meter.
Note that these are Model II regressions so the equations are the same
if PM is regressed versus cp or vice versa. For comparison,
the relationships between particle concentration and attenuation in
surface waters of previous JGOFS programs were:
PM = 1022*cp North Atlantic Bloom Exp.
PM = 451*cp EqPac Spring Time Series
PM = 647*cp EqPac Fall Time Series
<b>Chlorophyll</b>
Chlorophyll-a fluorescence distribution in the Arabian Sea was
determined, in-situ, with a SeaTech Fluorometer. The fluorometer was
interfaced with the Sea-Bird CTD, and the data were acquired in the
same format as the transmissometer data. The Fluorometer is a standard
irradiation/emission system. When chlorophyll a is excited by blue
light (425 nm), it will fluoresce at a peak wavelength of 685 nm (red
light). The emission detector is filtered to a peak response in order
to make the measurement insensitive to the excitation source. The
amount of fluoresced light detected is converted to a voltage range of
0 to 5 volts. A signal gain of 10x was used, setting sensitivity to
3mg chl-a m^-3. The fluorometer is set to sample with a three second time
constant to smooth the data. A baffle has been placed in front of the
emission detector in an attempt to make it insensitive to ambient light
(SeaTech Fluorometer Manual). The SEASOFT software converts the
measured voltage into a relative chlorophyll-a value using the
equation:
[volts * signal gain/5] + offset = mg chl-a m^-3
These relative values were calibrated using discreet
chlorophyll samples (taken by various JGOFS scientists and analyzed
onboard the ship using a Turner Fluorometer). There is a good (r^2 =
0.90) linear correlation between fluorometer-determined chlorophyll-a
fluorescence, and the chlorophyll-a concentrations determined using a
Turner fluorometer. Regressions were made for each cruise individually,
but the correlations (based on the standard deviation of the slope and
intercept) were improved when data from cruises TN049, TN050, and TN054
were combined. Prior to TN049, chlorophyll samples were taken from the
Trace-Metal rosette, which contained no CTD or fluorometer for accurate
depth or fluorescence measurements. We attempted a comparison between
standard CTD/fluorometer profiles made close in time to the Trace-Metal
casts on which chlorophyll measurements were made, but the lack of
accurate depths or water density for the discreet samples plus the
temporal variability between casts introduced too much scatter for a
useful correlation. There were too few chlorophyll a measurements made
on the standard CTD casts during TN043 and TN045 to independently
calibrate the fluorometer. This added to the appeal of a general
calibration for the fluorescence signal for all cruises, though we
recognize that data for two cruises were not included. We emphasize
for future work that it is necessary to have a fluorometer and CTD on
the rosette at the time chlorophyll samples are being taken in order to
accurately calibrate the fluorescence signal. Furthermore continuous
profiles from a fluorometer provide higher resolution than discreet
samples alone.
Slightly different slopes and intercepts were observed in the
fluorescence/chlorophyll correlations for samples above and below the
chlorophyll maximum. Therefore the depth of the chlorophyll maximum was
determined by visual inspection of each profile (to avoid confusion
with individual spikes) and the samples were divided into two
categories, separated at a depth 10 m beneath the maximum fluorescence
value. The assumption (substantiated by inspection of the data) is that
chlorophyll-containing particles within the subsurface chlorophyll
maximum are more similar to those above the maximum than below. A model
II linear regression on each group of data indicated a very slight
difference in slopes between the two groups, but a substantial offset
in the intercepts. This results in a difference in the concentration of
predicted chlorophyll based on the fluorescence above and below the
chlorophyll maximum. Similar differences in chlorophyll fluorescence
above and below the chlorophyll maximum were noticed by Pak et
al.(1988). Equations are provided here for both regions in the Arabian Sea.
Above the depth of the chlorophyll maximum:
Chl a = 0.357*Fl + 0.078 (r^2 = 0.86)
Below the depth of the chlorophyll maximum:
Chl a = 0.389*Fl - 0.05 (r^2 = 0.93)
<b>LSS - SeaTech Light Scattering Sensor</b>
Light scattering due to particles was monitored using a SeaTech
Light Scattering Sensor (LSS). The LSS projects light from two 880 nm
(infrared) LEDs into a sampling volume that varies depending upon the
concentration of particulate matter, but that is roughly the shape of a
stretched balloon. Back-scattered light from the particulate matter is
measured by a detector. The range on the LSS was set to 0 - 33 mg/l.
The amount of light detected is scaled to a 0-5 volt output, but in the
Arabian Sea most values were less than 0.5 volts. The LSS output
depends upon the nature of the particulate matter and will vary with
changes in particle size distribution, shape, index of refraction,
organic/inorganic content etc. Therefore the LSS requires site-specific
calibration. The LSS was interfaced with the SeaBird CTD and the data
were handled in the same format as the transmissometer and fluorometer
data.
</pre>
from Cruise: TT045 <p>Beam Attenuation Coefficient, Light Scattering, Fluorescence protocols</p>
<p> </p>
<h6>Wilford Gardner, Jan Gundersen, Mary Jo Richardson.<br />
Texas A&M University</h6>
<p> </p>
<pre>
<strong>Data Reduction Scheme</strong>
The primary purpose for measuring the beam attenuation
in JGOFS programs is to determine the concentration and distribution of
particulate matter (PM) or particulate organic carbon (POC) in the
water with continuous profiling rather than with limited discrete
samples. Towards this end, a 25 cm Sea Tech Transmissometer was
interfaced with the University of Washington's SeaBird CTD for all
Arabian Sea cruises. Transmissometer data were analyzed for the five
process cruises (TN043, TN045, TN049, TN050 and TN054) that occupied a
standard set of stations. Data from the raw CTD files were binned at 2
db intervals through SeaBird's SEASOFT program, which has a spike
removal subroutine which we have tested and found to remove
transmissometer data spikes properly. The data were corrected for
factory and field air calibrations. Beam transmission was converted to
beam attenuation coefficients using c=-(1/r)*ln(%Tr/100) where c=beam
attenuation coefficient (m^-1), r=beam path length (m), and Tr=% beam
transmission.
The Arabian Sea data set presented some challenges because 1-4
different transmissometers were used on any given cruise, complicating
the data calibration. It is impractical to do a proper bench or air
calibration prior for each CTD cast since the deck of the ship is not
always a clean environment and atmospheric conditions can change
rapidly and affect the air readings. One calibration method is to
compare the beam attenuation at depth where the particle concentration
is relatively invariant. The primary concern is ensuring that the
optical windows are uniformly clean, which is best determined by
comparing adjacent profiles. Unfortunately, many of the CTD casts
extended only to 150 m or less, which was usually shallower than the
particle minimum. Furthermore, the stations covered a wide geographic
area, so it is more likely that the particle minimum at depth could
vary. The primary method for comparing the beam attenuation signal to
particulate matter (PM) concentration or particulate organic carbon
(POC) concentration is to filter water samples and determine the dry
weight using stable filters (0.4 um pore size Poretics filters in this
case), or the amount of organic carbon on a glass fiber filter (0.7 um
nominal pore size). The beam c data for those bottle depths (chosen as
the cp value of the 2 db bin within which the sample depth fell) are
then regressed against PM or POC using a Model II regression to
determine the intercept where the concentration of particles in the
water equals zero. Theoretically this value should be 0.364 since the
transmissometers are set at the factory to read 0.364 in particle-free
water. PM was filtered on four of the five cruises where beam c was
analyzed. POC was measured on the one cruise for which no PM
measurements were made (TN049) as well as most of the other cruises.
In order to determine the attenuation specific to particulate matter,
the attenuation due to water must be subtracted from the beam c values
( cp = c - cw). Practically, cw is determined as the minimum
attenuation measured during each cruise. It must be noted that this
minimum attenuation value is the "cleanest" water observed and is not
particle free. Thus, the regressions of the cp data versus particle
concentrations must be adjusted.
A prediction of the PM concentration can be obtained from the
resulting equations for each cruise:
TN043 -> PM = 602 * cp (r^2 = 0.86)
TN045 -> PM = 483 * cp (r^2 = 0.87)
TN050 -> PM = 687 * cp (r^2 = 0.92)
TN054 -> PM = 615 * cp (r^2 = 0.86)
PM is in ug/Kg, and cp is attenuation per meter.
Note that these are Model II regressions so the equations are the same
if PM is regressed versus cp or vice versa. For comparison,
the relationships between particle concentration and attenuation in
surface waters of previous JGOFS programs were:
PM = 1022*cp North Atlantic Bloom Exp.
PM = 451*cp EqPac Spring Time Series
PM = 647*cp EqPac Fall Time Series
<strong>Chlorophyll</strong>
Chlorophyll-a fluorescence distribution in the Arabian Sea was
determined, in-situ, with a SeaTech Fluorometer. The fluorometer was
interfaced with the Sea-Bird CTD, and the data were acquired in the
same format as the transmissometer data. The Fluorometer is a standard
irradiation/emission system. When chlorophyll a is excited by blue
light (425 nm), it will fluoresce at a peak wavelength of 685 nm (red
light). The emission detector is filtered to a peak response in order
to make the measurement insensitive to the excitation source. The
amount of fluoresced light detected is converted to a voltage range of
0 to 5 volts. A signal gain of 10x was used, setting sensitivity to
3mg chl-a m^-3. The fluorometer is set to sample with a three second time
constant to smooth the data. A baffle has been placed in front of the
emission detector in an attempt to make it insensitive to ambient light
(SeaTech Fluorometer Manual). The SEASOFT software converts the
measured voltage into a relative chlorophyll-a value using the
equation:
[volts * signal gain/5] + offset = mg chl-a m^-3
These relative values were calibrated using discreet
chlorophyll samples (taken by various JGOFS scientists and analyzed
onboard the ship using a Turner Fluorometer). There is a good (r^2 =
0.90) linear correlation between fluorometer-determined chlorophyll-a
fluorescence, and the chlorophyll-a concentrations determined using a
Turner fluorometer. Regressions were made for each cruise individually,
but the correlations (based on the standard deviation of the slope and
intercept) were improved when data from cruises TN049, TN050, and TN054
were combined. Prior to TN049, chlorophyll samples were taken from the
Trace-Metal rosette, which contained no CTD or fluorometer for accurate
depth or fluorescence measurements. We attempted a comparison between
standard CTD/fluorometer profiles made close in time to the Trace-Metal
casts on which chlorophyll measurements were made, but the lack of
accurate depths or water density for the discreet samples plus the
temporal variability between casts introduced too much scatter for a
useful correlation. There were too few chlorophyll a measurements made
on the standard CTD casts during TN043 and TN045 to independently
calibrate the fluorometer. This added to the appeal of a general
calibration for the fluorescence signal for all cruises, though we
recognize that data for two cruises were not included. We emphasize
for future work that it is necessary to have a fluorometer and CTD on
the rosette at the time chlorophyll samples are being taken in order to
accurately calibrate the fluorescence signal. Furthermore continuous
profiles from a fluorometer provide higher resolution than discreet
samples alone.
Slightly different slopes and intercepts were observed in the
fluorescence/chlorophyll correlations for samples above and below the
chlorophyll maximum. Therefore the depth of the chlorophyll maximum was
determined by visual inspection of each profile (to avoid confusion
with individual spikes) and the samples were divided into two
categories, separated at a depth 10 m beneath the maximum fluorescence
value. The assumption (substantiated by inspection of the data) is that
chlorophyll-containing particles within the subsurface chlorophyll
maximum are more similar to those above the maximum than below. A model
II linear regression on each group of data indicated a very slight
difference in slopes between the two groups, but a substantial offset
in the intercepts. This results in a difference in the concentration of
predicted chlorophyll based on the fluorescence above and below the
chlorophyll maximum. Similar differences in chlorophyll fluorescence
above and below the chlorophyll maximum were noticed by Pak et
al.(1988). Equations are provided here for both regions in the Arabian Sea.
Above the depth of the chlorophyll maximum:
Chl a = 0.357*Fl + 0.078 (r^2 = 0.86)
Below the depth of the chlorophyll maximum:
Chl a = 0.389*Fl - 0.05 (r^2 = 0.93)
<strong>LSS - SeaTech Light Scattering Sensor</strong>
Light scattering due to particles was monitored using a SeaTech
Light Scattering Sensor (LSS). The LSS projects light from two 880 nm
(infrared) LEDs into a sampling volume that varies depending upon the
concentration of particulate matter, but that is roughly the shape of a
stretched balloon. Back-scattered light from the particulate matter is
measured by a detector. The range on the LSS was set to 0 - 33 mg/l.
The amount of light detected is scaled to a 0-5 volt output, but in the
Arabian Sea most values were less than 0.5 volts. The LSS output
depends upon the nature of the particulate matter and will vary with
changes in particle size distribution, shape, index of refraction,
organic/inorganic content etc. Therefore the LSS requires site-specific
calibration. The LSS was interfaced with the SeaBird CTD and the data
were handled in the same format as the transmissometer and fluorometer
data.
</pre>
from Cruise: TT049 <span class="h3info">Beam Attenuation Coefficient, Light Scattering, Fluorescence
protocols</span><br>
<h6>Wilford Gardner, Jan Gundersen, Mary Jo Richardson.<br>
Texas A&M University </h6>
<pre><b>Data Reduction Scheme</b>
The primary purpose for measuring the beam attenuation
in JGOFS programs is to determine the concentration and distribution of
particulate matter (PM) or particulate organic carbon (POC) in the
water with continuous profiling rather than with limited discrete
samples. Towards this end, a 25 cm Sea Tech Transmissometer was
interfaced with the University of Washington's SeaBird CTD for all
Arabian Sea cruises. Transmissometer data were analyzed for the five
process cruises (TN043, TN045, TN049, TN050 and TN054) that occupied a
standard set of stations. Data from the raw CTD files were binned at 2
db intervals through SeaBird's SEASOFT program, which has a spike
removal subroutine which we have tested and found to remove
transmissometer data spikes properly. The data were corrected for
factory and field air calibrations. Beam transmission was converted to
beam attenuation coefficients using c=-(1/r)*ln(%Tr/100) where c=beam
attenuation coefficient (m^-1), r=beam path length (m), and Tr=% beam
transmission.
The Arabian Sea data set presented some challenges because 1-4
different transmissometers were used on any given cruise, complicating
the data calibration. It is impractical to do a proper bench or air
calibration prior for each CTD cast since the deck of the ship is not
always a clean environment and atmospheric conditions can change
rapidly and affect the air readings. One calibration method is to
compare the beam attenuation at depth where the particle concentration
is relatively invariant. The primary concern is ensuring that the
optical windows are uniformly clean, which is best determined by
comparing adjacent profiles. Unfortunately, many of the CTD casts
extended only to 150 m or less, which was usually shallower than the
particle minimum. Furthermore, the stations covered a wide geographic
area, so it is more likely that the particle minimum at depth could
vary. The primary method for comparing the beam attenuation signal to
particulate matter (PM) concentration or particulate organic carbon
(POC) concentration is to filter water samples and determine the dry
weight using stable filters (0.4 um pore size Poretics filters in this
case), or the amount of organic carbon on a glass fiber filter (0.7 um
nominal pore size). The beam c data for those bottle depths (chosen as
the cp value of the 2 db bin within which the sample depth fell) are
then regressed against PM or POC using a Model II regression to
determine the intercept where the concentration of particles in the
water equals zero. Theoretically this value should be 0.364 since the
transmissometers are set at the factory to read 0.364 in particle-free
water. PM was filtered on four of the five cruises where beam c was
analyzed. POC was measured on the one cruise for which no PM
measurements were made (TN049) as well as most of the other cruises.
In order to determine the attenuation specific to particulate matter,
the attenuation due to water must be subtracted from the beam c values
( cp = c - cw). Practically, cw is determined as the minimum
attenuation measured during each cruise. It must be noted that this
minimum attenuation value is the "cleanest" water observed and is not
particle free. Thus, the regressions of the cp data versus particle
concentrations must be adjusted.
A prediction of the PM concentration can be obtained from the
resulting equations for each cruise:
TN043 -> PM = 602 * cp (r^2 = 0.86)
TN045 -> PM = 483 * cp (r^2 = 0.87)
TN050 -> PM = 687 * cp (r^2 = 0.92)
TN054 -> PM = 615 * cp (r^2 = 0.86)
PM is in ug/Kg, and cp is attenuation per meter.
Note that these are Model II regressions so the equations are the same
if PM is regressed versus cp or vice versa. For comparison,
the relationships between particle concentration and attenuation in
surface waters of previous JGOFS programs were:
PM = 1022*cp North Atlantic Bloom Exp.
PM = 451*cp EqPac Spring Time Series
PM = 647*cp EqPac Fall Time Series
<b>Chlorophyll</b>
Chlorophyll-a fluorescence distribution in the Arabian Sea was
determined, in-situ, with a SeaTech Fluorometer. The fluorometer was
interfaced with the Sea-Bird CTD, and the data were acquired in the
same format as the transmissometer data. The Fluorometer is a standard
irradiation/emission system. When chlorophyll a is excited by blue
light (425 nm), it will fluoresce at a peak wavelength of 685 nm (red
light). The emission detector is filtered to a peak response in order
to make the measurement insensitive to the excitation source. The
amount of fluoresced light detected is converted to a voltage range of
0 to 5 volts. A signal gain of 10x was used, setting sensitivity to
3mg chl-a m^-3. The fluorometer is set to sample with a three second time
constant to smooth the data. A baffle has been placed in front of the
emission detector in an attempt to make it insensitive to ambient light
(SeaTech Fluorometer Manual). The SEASOFT software converts the
measured voltage into a relative chlorophyll-a value using the
equation:
[volts * signal gain/5] + offset = mg chl-a m^-3
These relative values were calibrated using discreet
chlorophyll samples (taken by various JGOFS scientists and analyzed
onboard the ship using a Turner Fluorometer). There is a good (r^2 =
0.90) linear correlation between fluorometer-determined chlorophyll-a
fluorescence, and the chlorophyll-a concentrations determined using a
Turner fluorometer. Regressions were made for each cruise individually,
but the correlations (based on the standard deviation of the slope and
intercept) were improved when data from cruises TN049, TN050, and TN054
were combined. Prior to TN049, chlorophyll samples were taken from the
Trace-Metal rosette, which contained no CTD or fluorometer for accurate
depth or fluorescence measurements. We attempted a comparison between
standard CTD/fluorometer profiles made close in time to the Trace-Metal
casts on which chlorophyll measurements were made, but the lack of
accurate depths or water density for the discreet samples plus the
temporal variability between casts introduced too much scatter for a
useful correlation. There were too few chlorophyll a measurements made
on the standard CTD casts during TN043 and TN045 to independently
calibrate the fluorometer. This added to the appeal of a general
calibration for the fluorescence signal for all cruises, though we
recognize that data for two cruises were not included. We emphasize
for future work that it is necessary to have a fluorometer and CTD on
the rosette at the time chlorophyll samples are being taken in order to
accurately calibrate the fluorescence signal. Furthermore continuous
profiles from a fluorometer provide higher resolution than discreet
samples alone.
Slightly different slopes and intercepts were observed in the
fluorescence/chlorophyll correlations for samples above and below the
chlorophyll maximum. Therefore the depth of the chlorophyll maximum was
determined by visual inspection of each profile (to avoid confusion
with individual spikes) and the samples were divided into two
categories, separated at a depth 10 m beneath the maximum fluorescence
value. The assumption (substantiated by inspection of the data) is that
chlorophyll-containing particles within the subsurface chlorophyll
maximum are more similar to those above the maximum than below. A model
II linear regression on each group of data indicated a very slight
difference in slopes between the two groups, but a substantial offset
in the intercepts. This results in a difference in the concentration of
predicted chlorophyll based on the fluorescence above and below the
chlorophyll maximum. Similar differences in chlorophyll fluorescence
above and below the chlorophyll maximum were noticed by Pak et
al.(1988). Equations are provided here for both regions in the Arabian Sea.
Above the depth of the chlorophyll maximum:
Chl a = 0.357*Fl + 0.078 (r^2 = 0.86)
Below the depth of the chlorophyll maximum:
Chl a = 0.389*Fl - 0.05 (r^2 = 0.93)
<b>LSS - SeaTech Light Scattering Sensor</b>
Light scattering due to particles was monitored using a SeaTech
Light Scattering Sensor (LSS). The LSS projects light from two 880 nm
(infrared) LEDs into a sampling volume that varies depending upon the
concentration of particulate matter, but that is roughly the shape of a
stretched balloon. Back-scattered light from the particulate matter is
measured by a detector. The range on the LSS was set to 0 - 33 mg/l.
The amount of light detected is scaled to a 0-5 volt output, but in the
Arabian Sea most values were less than 0.5 volts. The LSS output
depends upon the nature of the particulate matter and will vary with
changes in particle size distribution, shape, index of refraction,
organic/inorganic content etc. Therefore the LSS requires site-specific
calibration. The LSS was interfaced with the SeaBird CTD and the data
were handled in the same format as the transmissometer and fluorometer
data.
</pre>
from Cruise: TT054 <span class="h3info">Beam Attenuation Coefficient, Light Scattering, Fluorescence
protocols</span><br>
<h6>Wilford Gardner, Jan Gundersen, Mary Jo Richardson.<br>
Texas A&M University </h6>
<pre><b>Data Reduction Scheme</b>
The primary purpose for measuring the beam attenuation
in JGOFS programs is to determine the concentration and distribution of
particulate matter (PM) or particulate organic carbon (POC) in the
water with continuous profiling rather than with limited discrete
samples. Towards this end, a 25 cm Sea Tech Transmissometer was
interfaced with the University of Washington's SeaBird CTD for all
Arabian Sea cruises. Transmissometer data were analyzed for the five
process cruises (TN043, TN045, TN049, TN050 and TN054) that occupied a
standard set of stations. Data from the raw CTD files were binned at 2
db intervals through SeaBird's SEASOFT program, which has a spike
removal subroutine which we have tested and found to remove
transmissometer data spikes properly. The data were corrected for
factory and field air calibrations. Beam transmission was converted to
beam attenuation coefficients using c=-(1/r)*ln(%Tr/100) where c=beam
attenuation coefficient (m^-1), r=beam path length (m), and Tr=% beam
transmission.
The Arabian Sea data set presented some challenges because 1-4
different transmissometers were used on any given cruise, complicating
the data calibration. It is impractical to do a proper bench or air
calibration prior for each CTD cast since the deck of the ship is not
always a clean environment and atmospheric conditions can change
rapidly and affect the air readings. One calibration method is to
compare the beam attenuation at depth where the particle concentration
is relatively invariant. The primary concern is ensuring that the
optical windows are uniformly clean, which is best determined by
comparing adjacent profiles. Unfortunately, many of the CTD casts
extended only to 150 m or less, which was usually shallower than the
particle minimum. Furthermore, the stations covered a wide geographic
area, so it is more likely that the particle minimum at depth could
vary. The primary method for comparing the beam attenuation signal to
particulate matter (PM) concentration or particulate organic carbon
(POC) concentration is to filter water samples and determine the dry
weight using stable filters (0.4 um pore size Poretics filters in this
case), or the amount of organic carbon on a glass fiber filter (0.7 um
nominal pore size). The beam c data for those bottle depths (chosen as
the cp value of the 2 db bin within which the sample depth fell) are
then regressed against PM or POC using a Model II regression to
determine the intercept where the concentration of particles in the
water equals zero. Theoretically this value should be 0.364 since the
transmissometers are set at the factory to read 0.364 in particle-free
water. PM was filtered on four of the five cruises where beam c was
analyzed. POC was measured on the one cruise for which no PM
measurements were made (TN049) as well as most of the other cruises.
In order to determine the attenuation specific to particulate matter,
the attenuation due to water must be subtracted from the beam c values
( cp = c - cw). Practically, cw is determined as the minimum
attenuation measured during each cruise. It must be noted that this
minimum attenuation value is the "cleanest" water observed and is not
particle free. Thus, the regressions of the cp data versus particle
concentrations must be adjusted.
A prediction of the PM concentration can be obtained from the
resulting equations for each cruise:
TN043 -> PM = 602 * cp (r^2 = 0.86)
TN045 -> PM = 483 * cp (r^2 = 0.87)
TN050 -> PM = 687 * cp (r^2 = 0.92)
TN054 -> PM = 615 * cp (r^2 = 0.86)
PM is in ug/Kg, and cp is attenuation per meter.
Note that these are Model II regressions so the equations are the same
if PM is regressed versus cp or vice versa. For comparison,
the relationships between particle concentration and attenuation in
surface waters of previous JGOFS programs were:
PM = 1022*cp North Atlantic Bloom Exp.
PM = 451*cp EqPac Spring Time Series
PM = 647*cp EqPac Fall Time Series
<b>Chlorophyll</b>
Chlorophyll-a fluorescence distribution in the Arabian Sea was
determined, in-situ, with a SeaTech Fluorometer. The fluorometer was
interfaced with the Sea-Bird CTD, and the data were acquired in the
same format as the transmissometer data. The Fluorometer is a standard
irradiation/emission system. When chlorophyll a is excited by blue
light (425 nm), it will fluoresce at a peak wavelength of 685 nm (red
light). The emission detector is filtered to a peak response in order
to make the measurement insensitive to the excitation source. The
amount of fluoresced light detected is converted to a voltage range of
0 to 5 volts. A signal gain of 10x was used, setting sensitivity to
3mg chl-a m^-3. The fluorometer is set to sample with a three second time
constant to smooth the data. A baffle has been placed in front of the
emission detector in an attempt to make it insensitive to ambient light
(SeaTech Fluorometer Manual). The SEASOFT software converts the
measured voltage into a relative chlorophyll-a value using the
equation:
[volts * signal gain/5] + offset = mg chl-a m^-3
These relative values were calibrated using discreet
chlorophyll samples (taken by various JGOFS scientists and analyzed
onboard the ship using a Turner Fluorometer). There is a good (r^2 =
0.90) linear correlation between fluorometer-determined chlorophyll-a
fluorescence, and the chlorophyll-a concentrations determined using a
Turner fluorometer. Regressions were made for each cruise individually,
but the correlations (based on the standard deviation of the slope and
intercept) were improved when data from cruises TN049, TN050, and TN054
were combined. Prior to TN049, chlorophyll samples were taken from the
Trace-Metal rosette, which contained no CTD or fluorometer for accurate
depth or fluorescence measurements. We attempted a comparison between
standard CTD/fluorometer profiles made close in time to the Trace-Metal
casts on which chlorophyll measurements were made, but the lack of
accurate depths or water density for the discreet samples plus the
temporal variability between casts introduced too much scatter for a
useful correlation. There were too few chlorophyll a measurements made
on the standard CTD casts during TN043 and TN045 to independently
calibrate the fluorometer. This added to the appeal of a general
calibration for the fluorescence signal for all cruises, though we
recognize that data for two cruises were not included. We emphasize
for future work that it is necessary to have a fluorometer and CTD on
the rosette at the time chlorophyll samples are being taken in order to
accurately calibrate the fluorescence signal. Furthermore continuous
profiles from a fluorometer provide higher resolution than discreet
samples alone.
Slightly different slopes and intercepts were observed in the
fluorescence/chlorophyll correlations for samples above and below the
chlorophyll maximum. Therefore the depth of the chlorophyll maximum was
determined by visual inspection of each profile (to avoid confusion
with individual spikes) and the samples were divided into two
categories, separated at a depth 10 m beneath the maximum fluorescence
value. The assumption (substantiated by inspection of the data) is that
chlorophyll-containing particles within the subsurface chlorophyll
maximum are more similar to those above the maximum than below. A model
II linear regression on each group of data indicated a very slight
difference in slopes between the two groups, but a substantial offset
in the intercepts. This results in a difference in the concentration of
predicted chlorophyll based on the fluorescence above and below the
chlorophyll maximum. Similar differences in chlorophyll fluorescence
above and below the chlorophyll maximum were noticed by Pak et
al.(1988). Equations are provided here for both regions in the Arabian Sea.
Above the depth of the chlorophyll maximum:
Chl a = 0.357*Fl + 0.078 (r^2 = 0.86)
Below the depth of the chlorophyll maximum:
Chl a = 0.389*Fl - 0.05 (r^2 = 0.93)
<b>LSS - SeaTech Light Scattering Sensor</b>
Light scattering due to particles was monitored using a SeaTech
Light Scattering Sensor (LSS). The LSS projects light from two 880 nm
(infrared) LEDs into a sampling volume that varies depending upon the
concentration of particulate matter, but that is roughly the shape of a
stretched balloon. Back-scattered light from the particulate matter is
measured by a detector. The range on the LSS was set to 0 - 33 mg/l.
The amount of light detected is scaled to a 0-5 volt output, but in the
Arabian Sea most values were less than 0.5 volts. The LSS output
depends upon the nature of the particulate matter and will vary with
changes in particle size distribution, shape, index of refraction,
organic/inorganic content etc. Therefore the LSS requires site-specific
calibration. The LSS was interfaced with the SeaBird CTD and the data
were handled in the same format as the transmissometer and fluorometer
data.
</pre>
Specified by the Principal Investigator(s)
asNeeded
7.x-1.1
Biological and Chemical Oceanography Data Management Office (BCO-DMO)
Unavailable
508-289-2009
WHOI MS#36
Woods Hole
MA
02543
USA
info@bco-dmo.org
http://www.bco-dmo.org
Monday - Friday 8:00am - 5:00pm
For questions regarding this resource, please contact BCO-DMO via the email address provided.
pointOfContact
CTD Seabird 911
CTD Seabird 911
PI Supplied Instrument Name: CTD Seabird 911 PI Supplied Instrument Description:CTD measurements taken by a SBE9 and SBE 11 (SeaBird) CTD package. Instrument Name: CTD Sea-Bird 911 Instrument Short Name:CTD SBE 911 Instrument Description: The Sea-Bird SBE 911 is a type of CTD instrument package. The SBE 911 includes the SBE 9 Underwater Unit and the SBE 11 Deck Unit (for real-time readout using conductive wire) for deployment from a vessel. The combination of the SBE 9 and SBE 11 is called a SBE 911. The SBE 9 uses Sea-Bird's standard modular temperature and conductivity sensors (SBE 3 and SBE 4). The SBE 9 CTD can be configured with auxiliary sensors to measure other parameters including dissolved oxygen, pH, turbidity, fluorescence, light (PAR), light transmission, etc.). More information from Sea-Bird Electronics. Community Standard Description: http://vocab.nerc.ac.uk/collection/L22/current/TOOL0035/
SeaTech Fluorometer
SeaTech Fluorometer
PI Supplied Instrument Name: SeaTech Fluorometer PI Supplied Instrument Description:Chlorophyll-a fluorescence distribution in the Arabian Sea was
determined, in-situ, with a SeaTech Fluorometer. The fluorometer was
interfaced with the Sea-Bird CTD, and the data were acquired in the
same format as the transmissometer data. The Fluorometer is a standard
irradiation/emission system. When chlorophyll a is excited by blue
light (425 nm), it will fluoresce at a peak wavelength of 685 nm (red
light). The emission detector is filtered to a peak response in order
to make the measurement insensitive to the excitation source. The
amount of fluoresced light detected is converted to a voltage range of
0 to 5 volts. A signal gain of 10x was used, setting sensitivity to
3mg chl-a m^-3. The fluorometer is set to sample with a three second time
constant to smooth the data. A baffle has been placed in front of the
emission detector in an attempt to make it insensitive to ambient light(SeaTech Fluorometer Manual). Instrument Name: Sea Tech Fluorometer Instrument Short Name:Sea Tech Fluorometer Instrument Description: The Sea Tech chlorophyll-a fluorometer has internally selectable settings to adjust for different ranges of chlorophyll concentration, and is designed to measure chlorophyll-a fluorescence in situ. The instrument is stable with time and temperature and uses specially selected optical filters enabling accurate measurements of chlorophyll a. It can be deployed in moored or profiling mode. This instrument designation is used when specific make and model are not known. The Sea Tech Fluorometer was manufactured by Sea Tech, Inc. (Corvalis, OR, USA). Community Standard Description: http://vocab.nerc.ac.uk/collection/L05/current/113/
SeaTech Transmissometer
SeaTech Transmissometer
PI Supplied Instrument Name: SeaTech Transmissometer PI Supplied Instrument Description:A 25 cm Sea Tech Transmissometer was interfaced with the University of Washington's SeaBird CTD for all Arabian Sea cruises. Instrument Name: Sea Tech Transmissometer Instrument Short Name:Sea Tech Transmissometer Instrument Description: The Sea Tech Transmissometer can be deployed in either moored or profiling mode to estimate the concentration of suspended or particulate matter in seawater. The transmissometer measures the beam attenuation coefficient in the red spectral band (660 nm) of the laser lightsource over the instrument's path-length (e.g. 20 or 25 cm). This instrument designation is used when specific make and model are not known. The Sea Tech Transmissometer was manufactured by Sea Tech, Inc. (Corvalis, OR, USA). Community Standard Description: http://vocab.nerc.ac.uk/collection/L22/current/TOOL0003/
Cruise: TT043
TT043
R/V Thomas G. Thompson
Community Standard Description
International Council for the Exploration of the Sea
R/V Thomas G. Thompson
vessel
TT043
Michael R. Roman
University of Maryland Center for Environmental Science
http://osprey.bcodmo.org/datasetDeployment.cfm?ddid=2580&did=353&flag=view
Report describing TT043
Cruise: TT045
TT045
R/V Thomas G. Thompson
Community Standard Description
International Council for the Exploration of the Sea
R/V Thomas G. Thompson
vessel
TT045
John F. Marra
Lamont-Doherty Earth Observatory
Cruise: TT049
TT049
R/V Thomas G. Thompson
Community Standard Description
International Council for the Exploration of the Sea
R/V Thomas G. Thompson
vessel
TT049
Richard Barber
Duke University
Cruise: TT050
TT050
R/V Thomas G. Thompson
Community Standard Description
International Council for the Exploration of the Sea
R/V Thomas G. Thompson
vessel
TT050
Sharon L. Smith
University of Miami
Cruise: TT053
TT053
R/V Thomas G. Thompson
Community Standard Description
International Council for the Exploration of the Sea
R/V Thomas G. Thompson
vessel
TT053
William M. Balch
University of Miami
Cruise: TT054
TT054
R/V Thomas G. Thompson
Community Standard Description
International Council for the Exploration of the Sea
R/V Thomas G. Thompson
vessel
TT054
Wilford D. Gardner
Texas A&M University
Cruise: TT039
TT039
R/V Thomas G. Thompson
Community Standard Description
International Council for the Exploration of the Sea
R/V Thomas G. Thompson
vessel
TT039
Dr Louis A. Codispoti
Old Dominion University
http://usjgofs.whoi.edu/arabian-docs/smith-update.html
Report describing TT039
R/V Thomas G. Thompson
Community Standard Description
International Council for the Exploration of the Sea
R/V Thomas G. Thompson
vessel