Dataset: GP16 Water Mass Percentages

Name: Results from Optimum Multiparameter Water Mass Analysis (OMPA) obtained using temperature, salinity, nutrient, and oxygen data from R/V Thomas G. Thompson cruise TN303 in the Eastern Tropical Pacific from October to December 2013
Published: 2017-08-17
Keywords: oceans

Cite This Dataset

Spatial Extent: N:-10.25 E:-77.3761 S:-16.0006 W:-152.0006

Temporal Extent: 2013-10-29 - 2013-12-18

Project:

GEOTRACES Peru-Tahiti Nitrogen Isotope Measurements (EPZT Nitrogen Isotopes)

U.S. GEOTRACES East Pacific Zonal Transect (U.S. GEOTRACES EPZT)

Measurement of Helium Isotopes, Tritium, Noble Gases, and Radiocarbon (EPZT Noble Gases He Tritium)

Program:

U.S. GEOTRACES (U.S. GEOTRACES)

Principal Investigator:

Karen L. Casciotti (Stanford University)

Co-Principal Investigator:

Mark A. Brzezinski (University of California-Santa Barbara, UCSB)

Gregory Cutter (Old Dominion University, ODU)

Christopher R. German (Woods Hole Oceanographic Institution, WHOI)

William J. Jenkins (Woods Hole Oceanographic Institution, WHOI)

James W. Moffett (University of Southern California, USC)

James H. Swift (University of California-San Diego, UCSD-SIO)

BCO-DMO Data Manager:

Shannon Rauch (Woods Hole Oceanographic Institution, WHOI BCO-DMO)

Version:

17 August 2017

Version Date:

2017-08-17

Restricted:

Validated:

Yes

Current State:

Final no updates expected

Data URL:

https://www.bco-dmo.org/dataset/713003/data

Results from Optimum Multiparameter Water Mass Analysis (OMPA) obtained using temperature, salinity, nutrient, and oxygen data from R/V Thomas G. Thompson cruise TN303 in the Eastern Tropical Pacific from October to December 2013

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Description

Water mass percentage data from Optimum Multiparameter Water Mass Analysis (OMPA) for GP16 obtained using temperature, salinity, nutrient, and oxygen data.

Acquisition Description

We use the Optimum Multiparameter Analysis (OMPA) method to determine water mass percentages along the GP16 transect. This involves the use of hydrographic measurements from GP16 (temperature, salinity, oxygen, and nutrients), which can be found in a separate BCO-DMO dataset (see CTD - ODF Bottle). For samples having potential density anomalies greater than 27 kg m-3, the OMPA was conducted according to the procedure outlined by Tomczak (1981), Tomczak and Large (1989), and others. For samples in the thermocline, defined as those samples having densities between 26 and 27, we use the 'thermocline array' method to determine the water mass fractions, according to the procedure outlined by Jenkins et al. (2015). Samples having densities less than 26 kg m-3 were not included in the water mass analysis. The uncertainty in water mass percentage is calculated using a Monte Carlo routine, where the defined properties of each water mass are varied to encompass the reported range of properties in that water mass. Lastly, the signal to noise ratio is calculated by dividing the percentage of given water mass in a each sample by the uncertainty of that water mass.

Processing Description

BCO-DMO GEOTRACES Processing:
As was done for the GEOTRACES-NAT data, BCO-DMO added standard US GEOTRACES information, such as the US GEOTRACES event number, to each submitted dataset lacking this information. To accomplish this, BCO-DMO compiled a 'master' dataset composed of the following parameters:

cruise_id, EXPOCODE,SECT_ID, STNNBR, CASTNO, GEOTRC_EVENTNO, GEOTRC_SAMPNO, GEOTRC_INSTR, SAMPNO, GF_NO, BTLNBR, BTLNBR_FLAG_W, DATE_START_EVENT, TIME_START_EVENT, ISO_DATETIME_UTC_START_EVENT, EVENT_LAT, EVENT_LON, DEPTH_MIN, DEPTH_MAX, BTL_DATE, BTL_TIME, BTL_ISO_DATETIME_UTC, BTL_LAT, BTL_LON, ODF_CTDPRS, SMDEPTH, FMDEPTH, BTMDEPTH, CTDPRS, CTDDEPTH.

This added information will facilitate subsequent analysis and inter comparison of the datasets.

Bottle parameters in the master file were taken from the GT-C_Bottle and ODF_Bottle datasets. Non-bottle parameters, including those from GeoFish tows, Aerosol sampling, and McLane Pumps, were taken from the TN303 Event Log (version 30 Oct 2014). Where applicable, pump information was taken from the PUMP_Nuts_Sals dataset.

A standardized BCO-DMO method (called "join") was then used to merge the missing parameters to each US GEOTRACES dataset, most often by matching on sample_GEOTRC or on some unique combination of other parameters.

If the master parameters were included in the original data file and the values did not differ from the master file, the original data columns were retained and the names of the parameters were changed from the PI-submitted names to the standardized master names. If there were differences between the PI-supplied parameter values and those in the master file, both columns were retained. If the original data submission included all of the master parameters, no additional columns were added, but parameter names were modified to match the naming conventions of the master file.

See the dataset parameters documentation for a description of which parameters were supplied by the PI and which were added via the join method.

More Information about this dataset

Funding Sources

Funding Source	Award Number
NSF Division of Ocean Sciences	OCE-1233339
NSF Division of Ocean Sciences	OCE-1130870
NSF Division of Ocean Sciences	OCE-1232991
NSF Division of Ocean Sciences	OCE-1130245
NSF Division of Ocean Sciences	OCE-1233028

Deployments

Deployment	Synonyms	Start Date	Platform	Investigator
TN303	GEOTRACES EPZT GEOTRACES East Pacific Zonal Transect (EPZT) GT13 325020131025 GP16	2013-10-25	R/V Thomas G. Thompson	James W. Moffett (Chief Scientist) Gregory Cutter (Co-Chief Scientist) Christopher R. German (Co-Chief Scientist)	data info

Instruments

CTD Sea-Bird SBE 911plus

(more info)

Short Name: CTD SBE 911plus

Community Standard Description

Generic Description

The Sea-Bird SBE 911plus is a type of CTD instrument package for continuous measurement of conductivity, temperature and pressure. The SBE 911plus includes the SBE 9plus Underwater Unit and the SBE 11plus Deck Unit (for real-time readout using conductive wire) for deployment from a vessel. The combination of the SBE 9plus and SBE 11plus is called a SBE 911plus. The SBE 9plus uses Sea-Bird's standard modular temperature and conductivity sensors (SBE 3plus and SBE 4). The SBE 9plus CTD can be configured with up to eight auxiliary sensors to measure other parameters including dissolved oxygen, pH, turbidity, fluorescence, light (PAR), light transmission, etc.). more information from Sea-Bird Electronics

PI supplied instrument name:

Dataset-specific description

Niskin bottle

(more info)

Short Name: Niskin bottle

Community Standard Description

Generic Description

A Niskin bottle (a next generation water sampler based on the Nansen bottle) is a cylindrical, non-metallic water collection device with stoppers at both ends. The bottles can be attached individually on a hydrowire or deployed in 12, 24, or 36 bottle Rosette systems mounted on a frame and combined with a CTD. Niskin bottles are used to collect discrete water samples for a range of measurements including pigments, nutrients, plankton, etc.

PI supplied instrument name:

Dataset-specific description

Parameters

Supplied Name	Supplied description	Supplied Units	Standard Name
cruise_id	Cruise identification	unitless	cruise_id
GEOTRC_INSTR	Sampling instrument; added from BCO-DMO EPZT master data file	unitless	instrument
STNNBR	Station number	unitless	station
LATITUDE	Station latitude (south is negative)	decimal degrees	lat
LONGITUDE	Station longitude (west is negative)	decimal degrees	lon
GEOTRC_SAMPNO	Unique GEOTRACES sample number	unitless	sample
GEOTRC_EVENTNO	GEOTRACES event number; added from BCO-DMO EPZT master data file	unitless	event
CASTNO	Cast number; added from BCO-DMO EPZT master data file	unitless	cast
CTDPRS	CTD pressure; added from BCO-DMO EPZT master data file	decibars (db)	press
CTDDEPTH	CTD bottle firing depth; added from BCO-DMO EPZT master data file	meters (m)	depth
SAMPNO	Sequential sample number within the cast (usually corresponds to bottle number); added from BCO-DMO EPZT master data file	unitless	bottle
BTLNBR	Bottle number; typically 1-24; added from BCO-DMO EPZT master data file	unitless	bottle
BTLNBR_FLAG_W	Bottle number quality flag; follows WOCE conventions. 2 = no problems noted; 3 = leaking; 4 = did not trip correctly; 9 = samples not drawn from this bottle. Added from BCO-DMO EPZT master data file	unitless	flag
BTL_ISO_DATETIME_UTC	Date and time, formatted to the ISO 8601 standard, at the time of bottle firing. Format: YYYY-MM-DDTHH:MM:SS[.xx]Z	unitless	ISO_DateTime_UTC
BTL_LAT	Latitude of bottle firing; north is positive. Added from BCO-DMO EPZT master data file	decimal degrees	lat
BTL_LON	Lonitude of bottle firing; east is positive. Added from BCO-DMO EPZT master data file	decimal degrees	lon
ESSW_PCT	the amount of Equatorial Subsurface Water in a sample, in units of percent	percent (%)	unknown
ESSW_UNCT	the uncertainty in the percent of Equatorial Subsurface Water, in units of percent	percent (%)	unknown
ESSW_STN	the signal to noise ratio for Equatorial Subsurface Water	dimensionless	unknown
ESPIW_PCT	the amount of Eastern South Pacific Intermediate Water, in units of percent	percent (%)	unknown
ESPIW_UNCT	the uncertainty of Eastern South Pacific Intermediate Water, in units of percent	percent (%)	unknown
ESPIW_STN	the signal to noise ratio of Eastern South Pacific Intermediate Water	dimensionless	unknown
SPCW_PCT	the amount of South Pacific Central Water in a sample, in units of percent	percent (%)	unknown
SPCW_UNCT	the uncertainty in South Pacific Central Water, in units of percent	percent (%)	unknown
SPCW_STN	the signal to nose ratio of South Pacific Central Water	dimensionless	unknown
AAIW_PCT	the amount of Antarctic Intermediate Water in a sample, in units of percent	percent (%)	unknown
AAIW_UNCT	the uncertainty of Antarctic Intermediate Water, in units of percent	percent (%)	unknown
AAIW_STN	the signal to noise ratio of Antarctic Intermediate Water	dimensionless	unknown
EQPIW_PCT	the amount of Equatorial Pacific Intermediate Water in a sample, in units of percent	percent (%)	unknown
EQPIW_UNCT	the uncertainty in Equatorial Pacific Intermediate Water, in units of percent	percent (%)	unknown
EQPIW_STN	the signal to noise ratio of Equatorial Pacific Intermediate Water	dimensionless	unknown
UCDW_PCT	the amount of Upper Circumpolar Deep Water in a sample, in units of percent	percent (%)	unknown
UCDW_UNCT	the uncertainty of Upper Circumpolar Deep Water, in units of percent	percent (%)	unknown
UCDW_STN	the signal to noise ratio of Upper Circumpolar Deep Water	dimensionless	unknown
PDW_PCT	the amount of Pacific Deep Water in a sample, in units of percent	percent (%)	unknown
PDW_UNCT	the uncertainty of Pacific Deep Water, in units of percent	percent (%)	unknown
PDW_STN	the signal to noise ratio in Pacific Deep Water	dimensionless	unknown
LCDW_PCT	the amount of Lower Circumpolar Deep Water in a sample, in units of percent	percent (%)	unknown
LCDW_UNCT	the uncertainty of Lower Circumpolar Deep Water, in units of percent	percent (%)	unknown
LCDW_STN	the signal to noise ratio in Lowe Circumpolar Deep Water	dimensionless	unknown
AABW_PCT	the amount of Antarctic Bottom Water in a sample, in units of percent	percent (%)	unknown
AABW_UNCT	the uncertainty of Antarctic Bottom Water, in units of percent	percent (%)	unknown
AABW_STN	the signal to noise ratio in Antarctic Bottom Water	dimensionless	unknown
total	Sum of percentages for the sample	percent (%)	unknown

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Dataset: GP16 Water Mass Percentages