Dataset: GP16 Helium Isotopes and Noble Gas Concentrations

Name: Helium Isotopes and Noble Gas Concentrations from the 2013 Eastern Pacific Zonal Transect cruise on R/V Thomas G. Thompson (TN303) (US GEOTRACES EPZT project)
Published: 2017-03-02
Keywords: oceans

Cite This Dataset

Spatial Extent: N:-10.5003 E:-77.3761 S:-16.0006 W:-152.0006

Project:

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

U.S. GEOTRACES East Pacific Zonal Transect (GP16) (U.S. GEOTRACES EPZT)

Program:

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

Principal Investigator:

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

BCO-DMO Data Manager:

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

Version:

02 March 2017

Version Date:

2017-03-02

Restricted:

Validated:

Yes

Current State:

Final no updates expected

Helium Isotopes and Noble Gas Concentrations from the 2013 Eastern Pacific Zonal Transect cruise on R/V Thomas G. Thompson (TN303) (US GEOTRACES EPZT project)

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Description

Helium Isotopes and Noble Gas Concentrations from GEOTRACES 2013 Eastern Pacific Zonal Transect cruise (TN303).

Note: These data, originally served on 15 November 2016, were revised on 02 March 2017. A correction was made to Krypton samples that were done using peak height manometry. A correction for matrix effects of 0.65% during mass spectrometric analysis was neglected in the original submission, and has now been made.

Methods & Sampling

Noble gas and helium isotope samples were acquired by gravity-feeding from NISKIN bottle into lengths of 5/8" OD copper tubing which were cold-welded to form replicate ~45 g, helium-leak-tight samples (Young and Lupton 1983) and returned for shore-based sample extraction and mass-spectrometric analysis. Gases were quantitatively extracted in a bellows-compression UHV vacuum line and quantitatively transferred to ~30 ml aluminosilicate glass ampoules. The gases were purified and cryogenically separated in an automated mass spectrometer processing line (Stanley, Baschek et al. 2009). Abundances of the light noble gases (He, Ne, and Ar) were determined by QMS ion-current manometry against atmospheric standards to an accuracy 0.2% or better. For a subset of the samples, the heavy noble gases (Kr and Xe) were analyzed in a similar fashion subject to an empirical "matrix effect" correction (Stanley 2007), and these results are characterized by an uncertainty of order 0.3% and 1% for Kr and Xe concentrations respectively. The remainder of the Kr and Xe measurements were done using an improved isotope dilution ratiometry, with subsequent uncertainties of order 0.2%. The isotope dilution ratiometry involved the use of a mono-isotopic 78-Kr and 124-Xe spike combined with the measurement of two other isotopes (82-Kr, 86-Kr, 129-Xe, and 132-Xe) to correct for isotopic fractionation when comparing to running standards.

References:
Stanley, R. H. R. (2007). A Determination of Air-Sea Gas Exchange Processes and Upper Ocean Biological Production From Five Noble Gases and Tritiugenic Helium-3. PhD, MIT-WHOI Joint Program in Chemical Oceanography.

Stanley, R. H. R., B. Baschek, D. E. I. Lott and W. J. Jenkins (2009). "A new automated method for measuring noble gases and their isotopic ratios in water samples." Geochemistry Geophysics Geosystems 10(5): Q05008, doi:05010.01029/02009GC002429.

Young, C. and J. E. Lupton (1983). "An ultratight fluid sampling system using cold-welded copper tubing." EOS Transactions AGU 64: 735.

Data Processing Description

Additional columns (pressure, temperature, salinity, longitude, sigma_0 and gamma_n) provided in original data are included for reference only. All quality flags follow CCHDO/WOCE conventions.

BCO-DMO Processing Notes:
- modified parameter names to conform with BCO-DMO and GEOTRACES naming conventions;
- updated data on 02 March 2017: a correction was made to Krypton samples that were done using peak height manometry. A correction for matrix effects of 0.65% during mass spectrometric analysis was neglected in the original submission, and has now been made.

Additional 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.

Data Files

File
noble_gas_helium_joined.csv (Comma Separated Values (.csv), 137.97 KB) MD5:6e71e96eafc6c95cad4af97f96b6f1bd Primary data file for dataset ID 664696

More Information about this dataset

Funding Sources

Funding Source	Award Number
NSF Division of Ocean Sciences	OCE-1232991

Deployments

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

Instruments

Mass Spectrometer

Supplied Name:

Supplied Description:

Instrument Type

Generic Name: Mass Spectrometer

Acronym: Mass Spec

Community Identifier: http://vocab.nerc.ac.uk/collection/L05/current/LAB16/

Generic Description:

General term for instruments used to measure the mass-to-charge ratio of ions; generally used to find the composition of a sample by generating a mass spectrum representing the masses of sample components.

Niskin bottle

Supplied Name: NISKIN bottle

Supplied Description:

Instrument Type

Generic Name: Niskin bottle

Community Identifier: http://vocab.nerc.ac.uk/collection/L22/current/TOOL0412/

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.

Parameters

Date and time formats are described in python strftime() syntax.

Supplied Name	Supplied description	Supplied Units	Standard Name
CTDPRS	CTD pressure	decibars	press
BTL_LAT	Latitude of bottle firing; north is positive; joined from BCO-DMO GEOTRACES master file	decimal degrees	lat
BTL_LON	Lonitude of bottle firing; east is positive; joined from BCO-DMO GEOTRACES master file	decimal degrees	lon
CTDTMP	CTD temperature	degrees Celsius	temp
BTMDEPTH	Bottom depth; joined from BCO-DMO GEOTRACES master file	meters	depth_bottom
CTDDEPTH	CTD bottle firing depth; joined from BCO-DMO GEOTRACES master file	meters	depth
Ar_D_CONC_BOTTLE	Dissolved argon concentration in micromoles/kg	micromoles per kilogram	diss_noble_gas_conc
Ar_D_CONC_BOTTLE_ERR	Uncertainty in dissolved argon concentration in micromoles/kg	micromoles per kilogram	diss_noble_gas_conc
Kr_D_CONC_BOTTLE	Dissolved krypton concentration in nanomoles/kg	nanomoles per kilogram	diss_noble_gas_conc
Kr_D_CONC_BOTTLE_ERR	Uncertainty in dissolved krypton concentration in nanomoles/kg	nanomoles per kilogram	diss_noble_gas_conc
Xe_D_CONC_BOTTLE	Dissolved xenon concentration in nanomoles/kg	nanomoles per kilogram	diss_noble_gas_conc
Xe_D_CONC_BOTTLE_ERR	Uncertainty in dissolved xenon concentration in nanomoles/kg	nanomoles per kilogram	diss_noble_gas_conc
He_D_BOTTLE	Dissolved helium concentration in nanomoles/kg	nanomoles per kilogram	diss_noble_gas_conc
He_D_BOTTLE_ERR	Uncertainty in dissolved helium concentration in nanomoles/kg	nanomoles per kilogram	diss_noble_gas_conc
Ne_D_CONC_BOTTLE	Dissolved neon concentration in nanomoles/kg	nanomoles per kilogram	diss_noble_gas_conc
Ne_D_CONC_BOTTLE_ERR	Uncertainty in dissolved neon concentration in nanomoles/kg	nanomoles per kilogram	diss_noble_gas_conc
He_3_D_DELTA_BOTTLE	Helium isotope ratio anomaly in percent	percent	diss_noble_gas_conc
He_3_D_DELTA_BOTTLE_ERR	Uncertainty in helium isotope ratio anomaly in percent	percent	diss_noble_gas_conc
CTDSAL	CTD salinity	PSU	sal
Ne_D_CONC_BOTTLE_FLAG_W	Quality flag for dissolved neon concentration	unitless	q_flag
Ar_D_CONC_BOTTLE_FLAG_W	Quality flag for dissolved argon concentration	unitless	q_flag
GEOTRC_EVENTNO	GEOTRACES event number; joined from BCO-DMO GEOTRACES master file	unitless	event
CASTNO	Cast number	unitless	cast
SAMPNO	Sequential sample number within the cast (usually corresponds to bottle number).	unitless	bottle
Kr_D_CONC_BOTTLE_FLAG_W	Quality flag for dissolved krypton concentration	unitless	q_flag
GEOTRC_SAMPNO	Unique GEOTRACES sample number	unitless	sample
Xe_D_CONC_BOTTLE_FLAG_W	Quality flag for dissolved xenon concentration	unitless	q_flag
He_3_D_DELTA_FLAG_W	Quality flag for helium isotope ratio anomaly	unitless	q_flag
GEOTRC_INSTR	Sampling instrument; joined from BCO-DMO GEOTRACES master file	unitless	instrument
BTLNBR	Bottle number; typically 1-24; joined from BCO-DMO GEOTRACES master file	unitless	bottle
BTLNBR_FLAG_W	Bottle number quality flag; follows WOCE conventions. 2 = good; 3 = questionable; 4 = bad; 9 = missing data; joined from BCO-DMO GEOTRACES master file	unitless	flag
He_D_BOTTLE_FLAG_W	Quality flag for dissolved helium concentration	unitless	q_flag
cruise_id	Cruise identification	unitless	cruise_id
STNNBR	Station number	unitless	station
BTL_ISO_DATETIME_UTC	Date and time, formatted to the ISO 8601 standard, at the time of bottle firing; joined from BCO-DMO GEOTRACES master file	YYYY-MM-DDTHH:MM:SS[.xx]Z	ISO_DateTime_UTC

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Dataset: GP16 Helium Isotopes and Noble Gas Concentrations