Hydrographic
Team Activity Report (Healy 04-02)
15 May to 23
June 2004
Nome, Alaska to
Nome, Alaska
98 CTD
casts on 35 stations were attempted. One of these was aborted, with no CTD data
and no water samples, six additional casts were aborted, the CTD data were
reported, but there were no water samples.
These casts were:
Station Cast
003 01 CTD data reported, 12
bottles tripped.
006 02 CTD data reported, 12 bottles tripped.
016 01 CTD data reported, 4 bottles tripped.
016 03 CTD data not reported, no bottles
027 01 CTD data reported, no bottles.
031 03
CTD data reported, aborted mid down-cast
CTD
casts were performed with a rosette system consisting of a 12-place rosette
frame with 30 liter bottles and a 12-place SBE-32 Carousel pylon. Underwater electronic components consisted
of:
·
Sea-Bird
Electronics, Inc. (SBE) 911plus CTD,
·
WETLabs
C-Star transmissometer with a 25cm path length and 660nm wavelength,
·
Biospherical
Instruments, Inc. Photosynthetically Active Radiation (PAR) sensor,
·
Chelsea
MkIII Aquatracka fluorometer, and
·
Simrad,
5 volt - 500 meters altimeter.
Additionally,
a Dr. Haardt fluorometer designed to detect colored organic matter (CDOM) and a
Secchi disk were mounted on the CTD package. The CTD, transmissometer, and the
two fluorometers were mounted horizontally along the bottom of the rosette
frame. The PAR sensor was located at the top of the rosette. The surface PAR
sensor was located on the aft, starboard railing of the helicopter shack. All sensors except the Secchi disk were
interfaced with the CTD system. This instrument package provided pressure, dual
temperature and dual conductivity channels as well as light transmissivity and
fluorometric signals at a sample rate of 24 scans per second.
The
bottles on the rosette were General Oceanic 30 liter bottles. The bottles were
equipped with internal nylon coated springs and silicone o-rings which are used
to minimize toxicity to the sample. Bottle numbering is 1 to 12 with 1 tripped
first usually at the deepest sampling level and 12 tripped last at the
shallowest sampling level. The rosette system was suspended from a standard
UNOLS 3 conductor 0.322” electromechanical cable.
The CTD
used was serial number 09P24152-0638 and the sensor’s model and serial numbers
are listed in Table 1.
TABLE 1. Instrument/Sensor Serial Numbers
|
Primary Temperature |
Primary Conductivity |
Secondary Temperature |
Secondary Conductivity |
Pressure |
Transmissometer |
|
SBE 3plus |
SBE 4C |
SBE 3plus |
SBE 4C |
401K-105 |
C-Star |
|
03-2796 |
04-2545 |
03-2824 |
04-2568 |
83009 |
CST-390DR |
|
Oxygen |
Fluorometer |
PAR |
Surface PAR |
Altimeter |
|
SBE 43 |
Aqua 3 |
QSP-2300 |
QSR-240 |
807 |
|
0459 |
088233 |
4643 |
6367 |
9711090 |
TABLE 2. Instrument mounting
heights in reference to the bottom of the rosette frame.
|
Sensor |
Height above base of rosette |
|
Sensor |
Height above base of rosette |
|
Altimeter |
2 cm |
|
Pressure |
19cm |
|
Transmissometer |
8 cm |
|
T (pri) |
10 cm |
|
Fluorometer (Chelsea) |
10 cm |
|
|
|
|
Fluorometer (Haardt) |
8 cm |
|
Par |
215cm Sta. < 2000 m |
|
|
|
|
|
|
The
distance of the mid-points of the 30 L Niskin bottles from the bottom-mounted
sensors was ~1.19m. The 30 Liter Niskin bottles are ~1.0 m long. The secchi
disk was mounted 2.2m above the bottom of the rosette frame.
Bottle 7
was replaced after station 010. At
times the nylon coating on the springs broke down and some rust was apparent.
To minimize the occurrence of rust, the springs were inspected before the
cruise and, as feasible during the cruise. During the mid-cruise servicing of
the CTD/rosette system that occurred following station 021, all springs were
inspected and 6 were replaced. HLY0402 rosette operations were
continually beset by problems with bottle leaks caused by Niskin bottle end
o-rings falling out of position. Typically, each cast had one such
occurrence. Although some Niskin bottles were more prone than others to
have an o-ring problem, in general the problem shifted from bottle to bottle
between casts. Some of the problems were gross, i.e. the o-ring would be
visible out the side of the end cap, but others were more subtle. Every time an
o-ring problem was suspected, the o-ring was carefully inspected, and replaced
if necessary. Also, at several points during the cruise all o-rings were
inspected. The contents of various packages of spare o-rings were
measured to locate 'large' or 'small' o-rings (within the manufacturer's
tolerance), and a remedial 'large' set was installed. Another time Coast
Guard personnel replaced all the o-rings from their own supply. Yet all
these remedial attempts were to no particular avail. The problem bears
further thought toward a satisfactory solution.
Pre-cruise
laboratory calibrations of CTD pressure, temperature and conductivity sensors
were used to generate coefficients for the calculation of these parameters from
their respective sensor frequencies. The temperature and conductivity
calibrations were performed at Sea-Bird Electronics, Inc. in Bellevue,
Washington. Calibration of the pressure
sensor was performed by Scripps Institution of Oceanography, Shipboard
Technical Support/Oceanographic Data Facility (SIO/STS/ODF) personnel. The
Sea-Bird laboratory temperature calibrations were referenced to the
International Temperature Scale of 1990 (ITS-90).
The CTD
911plus was operated generally as suggested in the Sea-Bird CTD Operating and
Repair Manual, which contains a description of the system, its operation and
functions (Sea-Bird Electronics, Inc., 2002). One difference from Sea-Bird’s
operation is that data acquisition was started on deck. This procedure allows a
check of the pressure offset and an unblocked reading of the transmissometer.
The Seasoft acquisition program as described in the CTD Data Acquisition
Software Manual (Sea-Bird Electronics, Inc., 2001) provided
a real-time graphical display of selected parameters adequate to monitor CTD
performance and information for the selection of bottle-tripping depths. Raw
data from the CTD were archived on the PC’s hard disk at the full 24 Hz
sampling rate.
A CTD Station Sheet form was filled
in for each deployment, providing a record of times, positions, bottom depth,
bottle sampling depths, and every attempt to trip a bottle, as well as any
pertinent comments. When the equipment and personnel were ready, data
acquisition was started. The CTD
operator pressed a control key (flag), which appends a summary line into the
files created for “inventory” files.
This file contains a summary of the time, ship’s position, and current
scan number each time the control key is pressed. They are used as a reference to mark important events during the
cast, such as on deck pressure, when the lowering was initiated, when the
package was at the bottom, when bottles were tripped and the on-deck pressure
with ending position. After the initial
flag, the rosette/CTD system was lowered into the water and held at 5 meters
wire out for 3-5 minutes to permit activation of the CTD pumps and
equilibration of the sensors. Then, the
operator had the CTD raised to the surface, again created a flag, and simultaneously directed the
winch operator to begin lowering. The operator created a flag at the
deepest point of the cast. Bottom depths were calculated by combining the
distance above bottom, reported by the altimeter, and the maximum depth of the
CTD package when bottom altimeter readings were available. If there was no altimeter reading, then the
bottom depth is reported from the ship’s Bathy 2000 or Knudsen model 320B/R
depth recorder. These data, corrected
for the draft of the transducer, were logged in uncorrected meters (assuming a
sound velocity of 1500 m/sec). If the altimeter and depth recorder data were
unavailable, the final resort was to use depth data from the SeaBeam system
(corrected sound velocities).
The wire out corresponding to each bottle trip was written on the
station log and the trips were electronically flagged in the data file. The performance of all sensors was monitored
during the cast. After the rosette
recovery, the operator created a final flag denoting the end of the cast. Any
faulty equipment or exceptionally noisy data were noted on the log sheet.
Prior to station 007, position information was not being appended to every scan. The wrong configuration file was later inadvertently chosen and the absolute positions were not appended to the data for Stations 020 casts 3-7, 021 cast 01, 023 casts 1-1, 024 casts 2-3 and 025 cast 1.
CTD
values determined on deck before and after each cast were compared to determine
a pressure offset correction. The comparison suggested that no pressure offset
was necessary.
The temperature sensors were
calibrated in November of 2003. The
dual temperature sensors were monitored during the expedition and exhibited
good agreement. It appears that no
additional corrections need to be applied. A post-cruise calibration will be
performed.
Corrected CTD pressure and temperature values were used
with bottle salinities to back-calculate bottle conductivities. Comparison of
these bottle values with the CTD primary conductivity values indicated no
additional offset needed to be applied to the data.
A
WETLabs calibrated transmissometer was utilized throughout the cruise. An on deck calibration check was performed
and even though there was little degradation from the last calibration, the new
coefficients were applied to the data set.
The CTD
oxygen data are only intended for qualitative use. Similarly, the fluorometric and PAR data are not calibrated.
Sea-Bird
Seasoft CTD processing software was employed. The processing programs are
outlined below. A more complete
description may be found in the Sea-Bird Software Manual which is available
from the Sea-Bird website (www.seabird.com).
The
sequence of programs that were run in processing CTD data from this cruise are
as follows:
·
DATCNV - Converts data from raw
frequencies and voltages to corrected engineering units
·
WILDEDIT - Eliminates
large spikes
·
CELLTM - Applies
conductivity cell thermal mass correction
·
FILTER – A
low pass filter to smooth pressure for LOOPEDIT
·
LOOPEDIT - Marks
scans where velocity is less than selected value to avoid pressure reversals
from ship roll, or during bottle flushing.
·
DERIVE - Computes
calculated parameters
·
BINAVG - Average
data into desired pressure bins
The
quality control steps included:
·
Sensor
verification After
the CTD was set up and sensor serial numbers and sensor location was entered
into the computer, another check was made to verify that there were no
tabulation errors.
·
Seasoft
Configuration File
was reviewed to verify that individual sensors were represented correctly, with
the correct coefficients.
·
Temperature was verified by comparing primary
and secondary sensor data.
·
Conductivity was checked by comparison of the
two sensors with each other and with bottle salinity samples.
·
Position
Check A chart
of the ship’s track was produced and reviewed for any serious problems. The positions were acquired from the ship’s
Trimble P-code navigation system.
·
Visual
Check Plots of
each usable cast were produced and reviewed for any noise and spikes that may
have been missed by the processing programs.
The density profile was checked for inversions that might have been produced by sensor noise or response mismatches.
WHP
water bottle quality flags were assigned as defined in the WOCE Operations
Manual [Joyce]. These flags and interpretation are tabulated in the CTD and
Bottle Data Distribution, Quality Flags section of this document.
Fine
structure including minor density inversions that may appear in the upper ~ 10
m of the profiles is most likely caused by ship discharges/turbulence. To
minimize the ship effect, engine cooling water discharges were restricted to
the port side of the Healy. A “yo yo”
procedure was adopted to induce bottle flushing whenever waves and ship motion
were weak. This procedure was employed
for all bottle trips under quiescent conditions except for productivity casts,
and for some thin low salinity surface lenses.
In the latter cases, the CTD was raised slowly so as not to disturb the
thin low-salinity surface layers with the CTD wake, and the soak time was
relied on to flush the bottle. Even
though this procedure may not have adequately flushed the surface bottle, it
was sufficient to reveal some large salinity differences in the ~ 1m depth
interval separating the CTD sensor from the bottle mid-point. These situations occurred in melting ice
under low winds and waves, and it is suspected that the water may have been
stratified even within the surface Niskin bottle. Regardless of the procedure
employed, the CTD operators were instructed to wait for at least 1 minute
(typically > 1.5 minutes) before tripping the bottle.
All salinity, nutrient and dissolved oxygen data collected by the “service” team have gone through several stages of editing and are not likely to change significantly. The chlorophyll observations reported are, however, preliminary and may undergo significant post-cruise editing.
There
were five generic types of casts performed with differing sampling
protocols. Generally speaking, the
samplings during these casts were as follows, but there is some cast-to-cast
variation.
·
Hydrographic
o
Oxygen,
o
Total
CO2,
o
Total
Alkalinity,
o
Nutrients
o
Chlorophyll/Phaeophytin
o
Phytoplankton
o
Salinity
o
O18/O16
o
Benthic
o
Dissolved
Organic Matter/Particulate Organic Matter
o
Thorium-234
·
Productivity/Zooplankton
o
Oxygen
o
Oxygen Respiration
o
Productivity
o
Nutrients
o
Chlorophyll
o
HPLC
o
Bacteria
o
Micro
Zooplankton
o
Particulate
Organic Matter
o
Dissolved
Organic Matter/Lignin
o
Bio-Optics
o
Taxonomy
o
C13/N15
·
Bio-Markers
o
Nutrients
o
Particulate
Organic Matter
o
Dissolved
Organic Matter/Lignin
·
Radium
o
Nutrients
o
Radium
·
Zooplankton
o
Nutrients
o
Micro
Zooplankton
o
C13/N15
The
correspondence between individual sample containers and the rosette bottle from
which the sample was drawn was recorded on the sample log for the cast. This
log also included any comments or anomalous conditions noted about the rosette
and bottles.
Normal
sampling practice included opening the drain valve before the air vent on the
bottle, to check for air leaks. This observation together with other diagnostic
comments (e.g., "lanyard caught in lid", "valve left open")
that might later prove useful in determining sample integrity was routinely
noted on the sample log.
After the samples were drawn and analyzed, the next stage of processing involved merging the different data streams into a common file. The rosette cast and bottle numbers were the primary identification for all ODF-analyzed samples taken from the bottle, and were used to merge the analytical results with the CTD data associated with that bottle.
Diagnostic comments from the sample log, and notes from analysts and/or bottle data processors were entered into a computer file associated with each station (the "quality" file) as part of the quality control procedure. Sample data from bottles suspected of leaking were checked to see if the properties were consistent with the profile for the cast, with adjacent stations, and, where applicable, with the CTD data. Direct inspection of the tabular data, property-property plots and vertical sections were all employed to check the data. Revisions were made whenever there was an objective reason to delete, annotate or re-calculate a datum. WHP water sample codes were selected to indicate the reliability of the individual parameters affected by the comments. WHP bottle codes were assigned where evidence showed the entire bottle was affected, as in the case of a leak, or a bottle trip at other than the intended depth.
Specific data processing and techniques and additional quality control are included with the parameter write-up.
All pressures and temperatures
for the bottle data tabulation were obtained by averaging CTD data for a brief
interval at the time the bottle was closed and then applying the appropriate
calibration data.
The temperatures are reported
using the International Temperature Scale of 1990.
384 salinity samples were analyzed
in 14 analyses runs.
Salinity
samples were drawn into 200 ml high alumina borosilicate bottles, which were
rinsed three times with sample prior to filling. The bottles were sealed with
custom-made plastic insert thimbles and Nalgene screw caps. This container
provides very low container dissolution and sample evaporation.
A
Guildline Autosal 8400B #65-715, standardized with IAPSO Standard Seawater
(SSW) batch P-144, was used to measure the salinities. Prior to the analyses,
the samples were stored to permit equilibration to laboratory temperature,
usually 8-20 hours. The salinometer was
outfitted with an Ocean Scientific International interface for computer-aided
measurement. The salinometer was standardized with a fresh vial of standard
seawater (SSW) at the beginning of each analysis run. Instrument drift was determined by running a SSW vial after the
last sample was run through the autosal. The salinometer cell was flushed until
two successive readings met software criteria for consistency; these were then
averaged for a final result. The estimated accuracy of bottle salinities run at
sea is usually better than 0.002 PSU relative to the particular standard
seawater batch used.
The
temperature stability in the salinometer laboratory was good; variation was no
more than 1ºC during a run of samples.
The laboratory temperature was generally 2-3ºC lower than the Autosal
bath temperature.
463 samples were analyzed for
oxygen.
Samples were collected for dissolved oxygen analyses as the first sample after the rosette was brought on board. Using a Tygon drawing tube, nominal 125ml volume-calibrated iodine flasks were rinsed three times, then filled and allowed to overflow for approximately 3 flask volumes. The sample draw temperature was measured with a small platinum resistance thermometer embedded in the drawing tube. Reagents were added to fix the oxygen before stoppering. The flasks were shaken twice to assure thorough dispersion of the precipitate, once immediately after drawing, and then again after about 20 minutes. The samples were usually analyzed within a few hours of collection.
Thiosulfate normalities were calculated from each standardization and corrected to 20ºC. Periodically, the 20ºC normalities and the blanks were plotted versus time and were reviewed for possible problems. New thiosulfate normalities were recalculated as a linear function of time, if warranted. The oxygen data were recalculated using the smoothed normality and an averaged reagent blank. Oxygens were converted from milliliters per liter to micromoles per kilogram using the sampling temperature.
Dissolved
oxygen analyses were performed with an ODF-designed automated oxygen titrator
using photometric end-point detection based on the absorption of 365nm
wavelength ultra-violet light. The titration of the samples and the data
logging were controlled by PC software. Thiosulfate was dispensed by a Dosimat
665 buret driver fitted with a 1.0 ml buret. The ODF method used a whole-bottle
modified-Winkler titration following the technique of Carpenter (1965) with
modifications by Culberson (1991), but with higher concentrations of potassium
iodate standard (approximately 0.012N) and thiosulfate solution (55 g/l).
Standard KIO3 solutions prepared ashore were run at the beginning of each run.
Reagent and distilled water blanks were determined, to account for presence of
oxidizing or reducing materials.
Oxygen flask volumes were
determined gravimetrically with degassed deionized water to determine flask
volumes at ODF’s chemistry laboratory. This was done once before using flasks
for the first time and periodically thereafter when a suspect bottle volume was
detected. The volumetric flasks used in preparing standards were
volume-calibrated by the same method, as was the 10 ml Dosimat buret used to
dispense standard iodate solution.
Potassium iodate was obtained from
Johnson Matthey Chemical Co. and was reported by the supplier to be >99.4%
pure.
1229 samples were analyzed for
nutrients in 63 analyses runs.
Nutrient samples were drawn into 45 ml polypropylene, screw-capped “oak-ridge type” centrifuge tubes. The tubes were rinsed with 10% HCl and then with sample three times before filling. Standardizations were performed at the beginning and end of each group of analyses (typically 6-24 samples) with an intermediate concentration mixed nutrient standard, which was prepared prior to each run from a secondary standard in a low-nutrient seawater matrix. The secondary standards were prepared aboard ship by dilution from primary standard solutions. Dry standards were pre-weighed at the laboratory at ODF, and transported to the vessel for dilution to the primary standard. Sets of 6-7 different standard concentrations covering the range of sample concentrations were analyzed periodically to determine the deviation from linearity, if any, as a function of concentration for each nutrient analysis. A correction for non-linearity was applied to the final nutrient concentrations when necessary.
After
each group of samples was analyzed, the raw data file was processed to produce
another file of response factors, baseline values, and absorbances. These values were then checked for accuracy
against values taken from strip chart recordings. A stable deep seawater check
sample was run occasionally as a substandard check.
Nutrients,
when reported in micromoles per kilogram, were converted from micromoles per
liter by dividing by sample density calculated at 1 atm pressure (0 db), in
situ salinity, and the sample temperature measured at the time of analysis.
Nutrient analyses
(nitrate+nitrite, nitrite, phosphate, silicate, ammonium, and urea) were
performed on an ODF-modified 6-channel Technicon AutoAnalyzer II, generally
within a few hours after sample collection.
The samples were kept in the dark by covering with tin foil or
refrigerated at 4°C, if
necessary, but brought to within 5°C of lab temperature before analysis. The analog outputs from each of the six channels were digitized
and logged automatically by computer (PC) at 2-second intervals.
A modification of the Armstrong et
al. (Armstrong 1967) procedure was used for the analysis of nitrate and
nitrite. For the nitrate plus nitrite analysis, the seawater sample was passed
through a cadmium reduction column where nitrate was quantitatively reduced to
nitrite. The stream was then passed through a 15mm flowcell and the absorbance
measured at 540nm. The same technique
was employed for nitrite analysis, except the cadmium column was bypassed, and
a 50mm flowcell was used for measurement.
Periodic checks of the column efficiency were made by running alternate
equal concentrations of NO2 and NO3 through the NO3 channel to ensure that
column efficiencies were high (> 95%). Nitrite concentrations were
subtracted from the nitrate+nitrite values to obtain nitrate concentrations.
Phosphate was analyzed using a
modification of the Bernhardt and Wilhelms [Bernhardt 1967.] technique. The
reaction product was heated to ~55ºC to enhance color development, then passed
through a 50mm flowcell and the absorbance measured at 820m.
Silicate was analyzed using the
technique of Armstrong et al., (Armstrong, 1967). The sample was passed
through a 15mm flowcell and the absorbance measured at 660nm.
Ammonium was determined by the
Berthelot reaction (Patton and Crouch 1977) in which sodium hypochlorite and
phenol react with ammonium ion to produce indophenol blue, a blue
compound. The solution was heated to
55°C and passed through a 50mm flowcell at 640nm.
Urea was analyzed via a
modification of the method of Rahmatullah and Boyde (1980), which is based on
the classic diacetyl monoxime method. A
solution of diacetyl monoxime, thiosemicarbizide and acetone is followed by the
addition of ferric chloride, which acts as a catalyst. The resultant solution was heated to 90°C
and passed through a 50mm flowcell. The absorbance was measured at 520nm.
Na2SiF6, the
silicate primary standard, was obtained from Johnson Matthey Company and Fisher
Scientific and was reported by the suppliers to be >98% pure. Primary
standards for nitrate (KNO3), nitrite (NaNO2), and phosphate (KH2PO4)
were obtained from Johnson Matthey Chemical Company, and the supplier reported
purities of 99.999%, 97%, and 99.999%, respectively. Ammonia, (NH4(SO4)2), and
Urea primary standards were obtained from Fisher Scientific and reported to be
>99% pure.
WHP
water bottle quality flags were assigned as defined in the WOCE Operations
Manual [Joyce]. These flags and interpretation are tabulated in the Data
Distribution, Bottle Data, Quality Flags section of this document.
The CTD and bottle data can be obtained through the JOSS website, www.JOSS.ucar.edu/sbi. The data are reported using the WHP-Exchange (WOCE Hydrographic Program) format and the quality coding follows those outlined by the WOCE program (Joyce, 1994). In addition, the format can be obtained through the WOCE Hydrographic Program website, www.WHPO.ucsd.edu. The descriptions in this document have been edited from the reference to annotate the format specific to this data distribution. ASCII files for each station were created with comments recorded on the CTD Station Logs during data acquisition. These ASCII files include data processing comments noting any problems, the resolution, and footnoting that may have occurred. A separate ASCII file was also created with the comments from the Sample Log Sheets that include problems with the Niskin bottles that could compromise the samples. Comments arising from inspection and checking of the data are also included in the ASCII file. These comment files are also in the JOSS database.
4. The "missing value" for a data value is always defined as -999, but written in the decimal place format of the parameter in question. For example, a missing salinity would be written -999.0000 or a missing phosphate -999.00.
5. The first four characters of the EXPOCODE are the U.S. National Oceanographic Data Center (NODC) country-ship code, then followed by up to an 8 characters expedition name of cruise number, i.e. 31H1HLY0402.
|
1st line |
File type, here CTD, followed by a comma and a DATE_TIME stamp YYYYMMDDdivINSwho YYYY 4 digit year MM 2 digit month DD 2 digit day div division of Institution INS Institution name who initials of responsible person |
|
# lines |
A file may include 0-N optional lines at the start of a data file, each beginning with a "#" character and each ending with carriage return or end-of-line. Information relevant to file change/update history may be included here, for example. |
|
2nd line |
NUMBER_HEADERS = n (n = 10 in this table and the example_ct1.csv file.) |
|
3rd line |
EXPOCODE = [expocode] The expedition code, assigned by the user. |
|
4th line |
SECT_ID = [section] The SBI station specification. Optional. |
|
5th line |
STNNBR = [station] The originator's station number |
|
6th line |
CASTNO = [cast] The originator's cast number |
|
7th line |
DATE = [date] Cast date in YYYYMMDD integer format. |
|
8th line |
TIME = [time] Cast time that CTD was at the deepest sampling point. |
|
9th line |
LATITUDE = [latitude] Latitude as SDD.dddd where "S" is sign (blank or missing is positive), DD are degrees, and dddd are decimal degrees. Sign is positive in northern hemisphere, negative in southern hemisphere |
|
10th line |
LONGITUDE = [longitude] Longitude as SDDD.dddd where "S" is sign (blank or missing is positive), DDD are degrees, and dddd are decimal degrees. Sign is positive for "east" longitude, negative for "west" longitude |
|
11th line |
DEPTH = [bottom] Reported depth to bottom. Preferred units are "meters" and should be specified in Line 2. In general, corrected depths are preferred to uncorrected depths. Documentation accompanying data includes notes on methodology of correction. Optional. |
|
next line |
Parameter headings. |
|
next line |
Units. |
|
data lines |
A single _ct1.csv CTD data file will normally contain data lines for one CTD cast. |
|
END_DATA |
The line after the last data line must read END_DATA, and be followed by a carriage return or end of line. |
|
other lines |
Users may include any information they wish in 0-N optional lines at the end of a data file, after the END_DATA line. |
|
Parameter |
Units |
Format |
Comments |
|
CTDPRS |
DB |
F9.1 |
CTD pressure, decibars |
|
CTDPRS_FLAG_W |
|
I1 |
CTDPRS quality flag |
|
CTDTMP |
ITS-90 |
F9.3 |
CTD temperature, degrees C (ITS-90) |
|
CTDTMP_FLAG_W |
|
I1 |
CTDTMP quality flag |
|
CTDSAL |
|
F9.3 |
CTD salinity |
|
CTDSAL_FLAG_W |
|
I1 |
CTDSAL quality flag |
|
CTDOXY |
UMOL/KG |
F9.1 |
CTD oxygen, micromoles/kilogram |
|
CTDOXY_FLAG_W |
|
I1 |
CTDOXY quality flag |
|
XMISS |
%TRANS |
F7.1 |
Transmissivity, percent transmittance |
|
XMISS_FLAG_W |
|
I1 |
XMISS quality flag |
|
HAARDT |
VOLTS |
F8.3 |
CDOM Fluorometer, voltage |
|
HAARDT_FLAG_W |
|
I1 |
HAARDT quality flag |
|
FLUORO |
VOLTS |
F8.3 |
Fluorometer, voltage |
|
FLUORO_FLAG_W |
|
I1 |
Fluorometer quality flag |
|
PAR |
VOLTS |
F8.3 |
PAR, voltage |
|
PAR_FLAG_W |
|
I1 |
PAR quality flag |
|
SPAR |
VOLTS |
F8.3 |
Surface PAR, voltage |
|
SPAR_FLAG_W |
|
I1 |
Surface PAR quality flag |
|
CTD_DEP |
METERS |
F5.0 |
Depth |
|
|
|
|
|
CTD data quality flags were assigned to the CTDTMP (CTD temperature), CTDSAL (CTD salinity) and XMISS (Transmissivity) parameters as follows:
2 Acceptable measurement.
3 Questionable measurement. The data did not fit the station profile or adjacent station comparisons (or possibly bottle data comparisons). The data could be acceptable, but are open to interpretation.
4 Bad measurement. The CTD data were determined to be unusable.
5 Not reported. The CTD data could not be reported, typically when CTD salinity is flagged 3 or 4.
9 Not sampled. No operational sensor was present on this cast
WHP CTD data quality flags were assigned to the CTDOXY (CTD O2), FLUORO (Fluorometer), PAR (PAR), SPAR (Surface PAR), and HAARDT (Haardt Fluorometer CDOM) parameter as follows:
1 Not calibrated. Data are uncalibrated.
9
Not
sampled. No operational sensor was present on this cast. Either the sensor
cover was left on or the depth rating necessitated removal.
|
1st line |
File type, here BOTTLE, followed by a comma and a DATE_TIME stamp YYYYMMDDdivINSwho |
|
|
YYYY 4 digit
year |
|
#lines |
A file may include 0-N optional lines, typically at the start of a data file, but after the file type line, each beginning with a "#" character and each ending with carriage return or end-of-line. Information relevant to file change/update history of the file itself may be included here, for example. |
|
2nd line |
Column headings. |
|
3rd line |
Units. |
|
data lines |
As many data lines may be included in a single file as is convenient for the user, with the proviso that the number and order of parameters, parameter order, headings, units, and commas remain absolutely consistent throughout a single file. |
|
END_DATA |
The line after the last data line must read END_DATA. |
|
other lines |
Users may include any information they wish in 0-N optional lines at the end of a data file, after the END_DATA line. |
|
Parameter |
Format |
Description notes |
||
|
EXPOCODE |
A12 |
The expedition code, assigned by the user. |
||
|
SECT |
A7 |
The SBI station specification. Optional. |
||
|
STNNBR |
A6 |
The originator's station number. |
||
|
CASTNO |
I3 |
The originator's cast number. |
||
|
BTLNBR |
A7 |
The bottle identification number. |
||
|
BTLNBR_FLAG_W |
I1 |
BTLNBR quality flag. |
||
|
SAMPNO |
A7 |
Cast number *100+BTLNBR. Optional |
||
|
DATE |
I8 |
Cast date in YYYYMMDD integer format. |
||
|
JULIAN |
F8.4 |
Julian day and time as fraction of day of the bottle trip. |
||
|
LATITUDE |
F8.4 |
Latitude as SDD.dddd where "S" is sign (blank or missing is positive), DD are degrees, and dddd are decimal degrees. Sign is positive in northern hemisphere, negative in southern hemisphere |
||
|
LONGITUDE |
F9.4 |
Longitude as SDDD.dddd where "S" is sign (blank or missing is positive), DDD are degrees, and dddd are decimal degrees. Sign is positive for "east" longitude, negative for "west" longitude |
||
|
DEPTH |
I5 |
Reported depth to bottom. Preferred units are "meters" and should be specified in Line 2. In general, corrected depths are preferred to uncorrected depths. Documentation accompanying data includes notes on methodology of correction. Optional. |
||
|
|
|
|
|
|
|
Parameter |
Units |
Format |
Comments |
|
CTDPRS |
DB |
F9.1 |
CTD pressure, decibars |
|
CTDTMP |
ITS-90 |
F9.3 |
CTD temperature, degrees C, (ITS-90) |
|
CTDTMP_FLAG_W |
|
I1 |
CTDTMP quality flag |
|
CTDCOND |
MS/CM |
F9.3 |
CTD Conductivity, milliSiemens/centimeter |
|
CTDCOND_FLAG_W |
|
I1 |
CTDCOND quality flag |
|
CTDSAL |
|
F9.3 |
CTD salinity |
|
CTDSAL_FLAG_W |
|
I1 |
CTDSAL quality flag |
|
SALNTY |
|
F9.4 |
bottle salinity |
|
SALNTY_FLAG_W |
|
I1 |
SALNTY quality flag |
|
CTDOXY |
UMOL/KG |
F9.1 |
CTD oxygen, micromoles/kilogram |
|
CTDOXY_FLAG_W |
|
I1 |
CTDOXY quality flag |
|
CTDOXY |
ML/L |
F9.3 |
CTD oxygen, milliliters/liter |
|
CTDOXY_FLAG_W |
|
I1 |
CTDOXY quality flag |
|
OXYGEN |
UMOL/KG |
F9.1 |
bottle oxygen |
|
OXYGEN_FLAG_W |
|
I1 |
OXYGEN quality flag |
|
OXYGEN |
ML/L |
F9.3 |
bottle oxygen, milliliters/liter |
|
OXYGEN_FLAG_W |
|
I1 |
OXYGEN quality flag |
|
O2TEMP |
DEGC |
F9.1 |
Temperature of water from spigot during oxygen draw, degrees C |
|
SILCAT |
UMOL/KG |
F9.2 |
SILICATE, micromoles/kilogram |
|
SILCAT_FLAG_W |
|
I1 |
SILCAT quality flag |
|
SILCAT |
UMOL/L |
F9.2 |
SILCATE, micromoles/liter |
|
SILCAT_FLAG_W |
|
I1 |
SILCAT quality flag |
|
NITRAT |
UMOL/KG |
F9.2 |
NITRATE, micromoles/kilogram |
|
NITRAT_FLAG_W |
|
I1 |
NITRAT quality flag |
|
NITRAT |
UMOL/L |
F9.2 |
NITRATE, micromoles/liter |
|
NITRAT_FLAG_W |
|
I1 |
NITRAT quality flag |
|
NITRIT |
UMOL/KG |
F9.2 |
NITRITE, micromoles/kilogram |
|
NITRIT_FLAG_W |
|
I1 |
NITRIT quality flag |
|
NITRIT |
UMOL/L |
F9.2 |
NITRITE, micromoles/liter |
|
NITRIT_FLAG_W |
|
I1 |
NITRIT quality flag |
|
PHSPHT |
UMOL/KG |
F9.2 |
PHOSPHATE, micromoles/kilogram |
|
PHSPHT_FLAG_W |
|
I1 |
PHSPHT quality flag |
|
PHSPHT |
UMOL/L |
F9.2 |
PHOSPHATE, micromoles/liter |
|
PHSPHT_FLAG_W |
|
I1 |
PHSPHT quality flag |
|
NH4 |
UMOL/KG |
F9.2 |
AMMONIUM, micromoles/kilogram |
|
NH4_FLAG_W |
|
I1 |
NH4 quality flag |
|
NH4 |
UMOL/L |
F9.2 |
AMMONIUM, micromoles/liter |
|
NH4_FLAG_W |
|
I1 |
NH4 quality flag |
|
UREA |
UMOL/KG |
F9.2 |
UREA, micromoles/kilogram |
|
UREA_FLAG_W |
|
I1 |
UREA quality flag |
|
UREA |
UMOL/L |
F9.2 |
UREA, micromoles/liter |
|
UREA_FLAG_W |
|
I1 |
UREA quality flag |
|
FLUORO |
VOLTS |
F8.3 |
Fluorometer, voltage |
|
FLUORO_FLAG_W |
|
I1 |
Fluorometer quality flag |
|
PAR |
VOLTS |
F8.3 |
PAR, voltage |
|
PAR_FLAG_W |
|
I1 |
PAR quality flag |
|
SPAR |
VOLTS |
F8.3 |
Surface PAR, voltage |
|
SPAR_FLAG_W |
|
I1 |
Surface PAR quality flag |
|
N** |
UMOL/L |
F9.2 |
N**, micromoles/liter |
|
N**_FLAG_W |
|
I1 |
N** quality flag |
|
CHLORO |
UG/L |
F7.2 |
Chlorophyll, micrograms/liter |
|
CHLORO_FLAG_W |
|
I1 |
Chlorophyll quality flag |
|
PHAEO |
UG/L |
F7.2 |
Phaeophytin, micrograms/liter |
|
PHAEO_FLAG_W |
|
I1 |
Phaeophytin quality flag |
|
BTL_DEP |
METERS |
F5.0 |
bottle depth, meters |
|
BTL_LAT |
|
F8.4 |
Latitude at time of bottle trip, decimal degrees |
|
BTL_LONG |
|
F9.4 |
Longitude at time of bottle trip, decimal degrees |
|
|
|
|
|
CTD data quality flags were assigned to CTDPRS (CTD pressure), CTDTMP (CTD temperature), CTDCOND (CTD Conductivity), and CTDSAL (CTD salinity) as defined in Data Distribution, CTD Data, Quality Flags section of this document. CTDOXY (CTD O2), FLUORO (Fluorometer), PAR (PAR), and SPAR (Surface PAR) parameters are flagged with either a 2, acceptable or 9, not drawn.
Bottle quality flags were assigned to the BTLNBR (bottle number) as defined in the WOCE Operations Manual [Joyce] with the following additional interpretations:
2 No problems noted.
3
Leaking. An air
leak large enough to produce an observable effect on a sample is identified by
a flag of 3 on the bottle and a flag of 4 on the oxygen. (Small air leaks may have no observable
effect, or may only affect gas samples.)
4 Did not trip correctly. Bottles tripped at other than the intended depth were assigned a flag of 4. There may be no problems with the associated water sample data.
9 The samples were not drawn from this bottle.
WHP water sample quality flags were assigned to the water samples using the following criteria:
1 The sample for this measurement was drawn from the water bottle, but the results of the analysis were not (yet) received.
2 Acceptable measurement.
3 Questionable measurement. The data did not fit the station profile or adjacent station comparisons (or possibly CTD data comparisons). No notes from the analyst indicated a problem. The data could be acceptable, but are open to interpretation.
4 Bad measurement. The data did not fit the station profile, adjacent stations or CTD data. There were analytical notes indicating a problem, but data values were reported. Sampling and analytical errors were also flagged as 4.
5 Not reported. The sample was lost, contaminated or rendered unusable.
9 The sample for this measurement was not drawn.
Not all of the quality flags are necessarily used on this data set.
Armstrong,
F. A. J., Stearns, C. R., and Strickland, D. H., “The measurement of upwelling
and subsequent biological processes by means of the Technicon AutoAnalyzer and
associated equipment,” Deep-Sea Research, 14, pp. 381-389, (1967).
Bernhardt,
Wilhelms A., “The continuous determination of low level iron, soluble phosphate
and total phosphate with the AutoAnalyzer”, Technicon Symposia, I,
pp. 385-389 (1967).
Carpenter,
J. H., “The Chesapeake Bay Institute technique for the Winkler dissolved oxygen
method,” Limnology and Oceanography, 10, pp. 141-143 (1965).
Culberson,
C. H., Knapp, G., Stalcup, M., Williams, R.T., and Zemlyak, F., “A comparison
of methods for the determination of dissolved oxygen in seawater,” Report WHPO
91-2, WOCE Hydrographic Programme Office (Aug 1991).
Gordon,
L.I., Jennings, J.C., Ross, A.A. and J.M. Krest, “A Suggested Protocol for
Continuous Flow Automated Analysis of Seawater Nutrients in the WOCE
Hydrographic Program and the Joint Global Ocean Fluxes Study”. 1993. WOCE
Hydrographic Programs Office, Methods Manual WHPO 91-1.
Intergovernmental
Oceanographic Commission, Scientific Committee on Oceanic Research Manual and
Guides 29 Protocols for the Joint Global Ocean Flux Study (JGOFS) Core
Measurements. UNESCO, 170pp., (1994).
Joyce,
T. ed., and Corry, C. ed., “Requirements for WOCE Hydrographic Programme Data
Reporting,” Report WHPO 90-1, WOCE Report No. 67/91 3.1, pp. 52-55, WOCE
Hydrographic Programme Office, Woods Hole, MA, USA (May 1994, Rev. 2),
UNPUBLISHED MANUSCRIPT
Macdonald,
R.W., F. A. McLaughlin and C.S. Wong, “The storage of reactive silicate samples
by freezing,” Limnology and Oceanography, 31, pp. 1139-1142 (1986).
Patton,
C.J. and Crouch, S.R., “Spectrophotometric and kinetics investigation of the
Berthelot reaction for the determination of ammonia,” Analytical Chemistry,
49(3), pp.464-469 (1977).
Rahmatullah,
Mohammed, and Boyde, T.R.C, “Improvements in the determination of urea using
diacetyl monoxime; methods with and without deproteinisation,” Clinica
Chimica Acta, 107, pp.3-9 1980.
Sea-Bird
Electronics, Inc, CTD Data Acquisition Software Manual, March 2001.
Sea-Bird
Electronics, Inc., CTD Operating and Repair Manual, February 2002.