Dataset: LabSea_Hamme et al 2017

Name: Noble gas concentrations, N2/Ar and saturation anomalies (with associated CTD data) from the Labrador Sea in 2007, 2011, 2015, 2016 (N2:Ar Deep Tracer)
Published: 2017-12-06
Keywords: oceans

Cite This Dataset

Spatial Extent: N:60.4428 E:-48.542 S:55.4228 W:-56.5368

Temporal Extent: 2007-05-14 - 2016-05-14

Project:

The Marine Dissolved N2/Ar Ratio, A Tracer for Deep Ocean Denitrification? (N2:Ar Deep Tracer)

Principal Investigator:

Roberta C. Hamme (University of Victoria, UVic)

Co-Principal Investigator:

Steven R. Emerson (University of Washington, UW)

Igor Yashayaev (Bedford Institute of Oceanography, BIO)

BCO-DMO Data Manager:

Nancy Copley (Woods Hole Oceanographic Institution, WHOI BCO-DMO)

Version Date:

2017-12-06

Restricted:

Validated:

Yes

Current State:

Final no updates expected

Noble gas concentrations, N2/Ar and saturation anomalies (with associated CTD data) from the Labrador Sea in 2007, 2011, 2015, 2016 (N2:Ar Deep Tracer)

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Description

This data is provided free for educational and non-profit research purposes. Please cite the publication listed under Acquisition Description in any work that uses this database. If you would like to be apprised of any future corrections or updates to the data, send an e-mail to rhamme@uvic.ca. If you discover what you believe to be an error in the database, it is your responsibility to send an e-mail to rhamme@uvic.ca before using the data in a publication.

Both MatLab .mat databases and comma-delimited .csv text files are provided. These two formats contain identical information. The data from the paper is listed in order of collection (date). Different cruises can be identified by the cruise name or date.

Download the Matlab file: LabSea_Hammeetal2017-12-06

Methods & Sampling

Methodology is given in Hamme et al. (2017). Briefly, samples are collected through CO2-flushed tubing into ~180mL evacuated glass flasks until half full. Samples are weighed. The water is equilibrated with the headspace, then removed. Headspace gases are cryogenically purified to remove H2O and CO2 for N2/Ar samples or to remove all gases except noble gases for the noble gas samples. An additional aliquot of 38Ar is added to the noble gas samples along with a balance gas of either N2 or He. Samples are analyzed on a MAT 252 or 253 isotope ratio mass spectrometer for the noble gas and UVic N2/Ar samples, and on a Delta XL for the N2/Ar samples run at UW. Samples are analyzed against standards of similar composition. Standard gases are calibrated relative to air with assumed dry mole fractions of 1.818e-5 for Ne, 9.34e-3 for Ar, 1.141e-6 for Kr, and 0.78084 for N2.

Related Reference:
These data were published in Figures 1, 2 and 4 of:
Hamme, R. C., Emerson, S. R., Severinghaus, J. P., Long, M. C., & Yashayaev, I. (2017). Using noble gas measurements to derive air-sea process information and predict physical gas saturations. Geophysical Research Letters, 44, 9901–9909. https://doi.org/10.1002/2017GL075123

Data Processing Description

All samples were collected in duplicate. Only data for which both duplicates were successfully analyzed and whose standard deviation was within three times the overall dataset pooled standard deviation are included in this dataset.

BCO-DMO Processing Notes:
- added conventional header with dataset name, PI name, version date
- modified parameter names to conform with BCO-DMO naming conventions
- replaced commas and colons with semicolons

Data Files

File
LabSea_gas.csv (Comma Separated Values (.csv), 31.95 KB) MD5:2e4dec38a861b2d5c2b4db3192fab82e Primary data file for dataset ID 719989

More Information about this dataset

Funding Sources

Funding Source	Award Number
NSF Division of Ocean Sciences	OCE-1029299
National Sciences and Engineering Research Council of Canada	328290-2006
National Sciences and Engineering Research Council of Canada	329290-2012
National Sciences and Engineering Research Council of Canada	433898-2012
National Sciences and Engineering Research Council of Canada	433848-2012

Deployments

Deployment	Synonyms	Start Date	Platform	Investigator
18HU20070510	HUD2007-011 HUD2007011 2007011 18HU07011 2007 AR7W 2007 AZOMP	2007-05-10	CCGS Hudson	Dr Ross Hendry (Chief Scientist)	data info
18HU20110506	2011 AR7W 2011 AZOMP HUD2011009 18HU11009	2011-05-06	CCGS Hudson	Igor Yashayaev (Chief Scientist)	data info
18DL20150710	ArcticNet 1502 2015 Canadian Arctic GEOTRACES GEOTRACES GN02	2015-07-10	CCGS Amundsen	Roger Francois (Chief Scientist)	data info
18HU20150504	HUD2015006 18HU15006 2015 AR7W 2015 AZOMP	2015-05-04	CCGS Hudson	Igor Yashayaev (Chief Scientist)	data info
18HU20160430	2016 AR7W 2016 AZOMP HUD2016006 18HU16006	2016-04-30	CCGS Hudson	Igor Yashayaev (Chief Scientist)	data info

Instruments

Isotope-ratio Mass Spectrometer

Supplied Name: Thermo Finnigan MAT253

Supplied Description:

Instrument Type

Generic Name: Isotope-ratio Mass Spectrometer

Acronym: IR Mass Spec; IRMS

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

Generic Description:

The Isotope-ratio Mass Spectrometer is a particular type of mass spectrometer used to measure the relative abundance of isotopes in a given sample (e.g. VG Prism II Isotope Ratio Mass-Spectrometer).

Isotope-ratio Mass Spectrometer

Supplied Name: Thermo Finnigan MAT252

Supplied Description:

Instrument Type

Generic Name: Isotope-ratio Mass Spectrometer

Acronym: IR Mass Spec; IRMS

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

Generic Description:

The Isotope-ratio Mass Spectrometer is a particular type of mass spectrometer used to measure the relative abundance of isotopes in a given sample (e.g. VG Prism II Isotope Ratio Mass-Spectrometer).

Isotope-ratio Mass Spectrometer

Supplied Name: Thermo Finnigan Delta XL

Supplied Description:

Instrument Type

Generic Name: Isotope-ratio Mass Spectrometer

Acronym: IR Mass Spec; IRMS

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

Generic Description:

The Isotope-ratio Mass Spectrometer is a particular type of mass spectrometer used to measure the relative abundance of isotopes in a given sample (e.g. VG Prism II Isotope Ratio Mass-Spectrometer).

Parameters

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

Supplied Name	Supplied description	Supplied Units	Standard Name
niskin	number of the niskin that the water samples were drawn from.	unitless	bottle
cruisename	The EXPO number is listed first, followed by a more colloquial cruise name, followed by the ship name, separated by semicolons. In Matlab file, formatted as cell array of strings.	unitless	cruise_name
day	day of sample collection	unitless	day
depth	Depth	meters	depth
Ne	Ne concentration in umol/kg determined by combining mass spectrometric Ne/Ar ratio measurements with absolute Ar concentrations by Ar isotope dilution with 38Ar. As discussed in the paper: the Ne method uses a helium balance gas but is otherwise similar to that of Hamme and Severinghaus (2007) "Trace gas disequilibria during deep-water formation" Deep Sea Research I: 54(6):939-950. Standard gases are calibrated relative to air with assumed dry mole fractions of 1.818e-5 for Ne.	micromol/kilogram	diss_noble_gas_conc
Ar	Ar concentration in umol/kg determined by Ar isotope dilution with 38Ar. As discussed in the paper, the 2007 measurements follow Hamme and Severinghaus (2007) "Trace gas disequilibria during deep-water formation" Deep Sea Research I: 54(6):939-950 while the later measurements use a similar method but with a helium balance gas. Standard gases are calibrated relative to air with assumed dry mole fractions of 9.34e-3 for Ar.	micromol/kilogram	diss_noble_gas_conc
Kr	Kr concentration in umol/kg determined by combining mass spectrometric Kr/Ar ratio measurements with absolute Ar concentrations by Ar isotope dilution with 38Ar. As discussed in the paper, the 2007 measurements follow Hamme and Severinghaus (2007) "Trace gas disequilibria during deep-water formation" Deep Sea Research I: 54(6):939-950; while the later measurements use a similar method but with a helium balance gas. Standard gases are calibrated relative to air with assumed dry mole fractions of 1.141e-6 for Kr.	micromol/kilogram	diss_noble_gas_conc
N2Ar	N2/Ar ratio determined by mass spectrometry with no units. Samples from 2007 were analyzed at Scripps Institution of Oceanography by purification with heated copper to remove oxygen following T. Kobashi; J.P. Severinghaus and K. Kawamura (2008) "Argon and nitrogen isotopes of trapped air in the GISP2 ice core during the Holocene epoch (0-11500 B.P.): Methodology and implications for gas loss processes" Geochim. Cosmochim. Acta 72 (19):4675-4686; doi:10.1016/j.gca.2008.07.006. Measurements from later years were analyzed at University of Victoria following Emerson et al. (1999) "Accurate measurement of O2, N2, and Ar gases in water and the solubility of N2" Marine Chemistry 64:337-347. Standard gases are calibrated relative to air with assumed dry mole fractions of 9.34e-3 for Ar and 0.78084 for N2.	unitless	diss_noble_gas_conc
N2Ar_UW	Same as for N2Ar but for data analyzed at University of Washington following a method that includes a 36Ar spike but otherwise follows Emerson et al. (1999) "Accurate measurement of O2, N2, and Ar gases in water and the solubility of N2" Marine Chemistry 64:337-347. Standard gases are calibrated relative to air with assumed dry mole fractions of 9.34e-3 for Ar and 0.78084 for N2.	unitless	diss_noble_gas_conc
event	number of the cast event that the water samples were drawn from.	unitless	event
latitude	The latitude of the station in degrees North.	decimal degrees	lat
longitude	The longitude of the station in degrees East. Negative numbers indicate oW.	decimal degrees	lon
month	month of sample collection	unitless	month
Nesat	Saturation anomaly of Ne in percent. 0% indicates that the Ne concentration is equal to that expected at equilibrium for the potential temperature and salinity of the water. ie. Nesat = (Ne/Neeq - 1) *100 The Ne saturation anomaly is calculated relative to the solubility curve of Hamme and Emerson (2004) "The solubility of neon, nitrogen, and argon in distilled water and seawater" Deep-Sea Research I: 51(11):1517-1528.	percent	no_bcodmo_term
Arsat	Saturation anomaly of Ar in percent. 0% indicates that the Ar concentration is equal to that expected at equilibrium for the potential temperature and salinity of the water. ie. Arsat = (Ar/Areq - 1) *100 The Ar saturation anomaly is calculated relative to the solubility curve of Hamme and Emerson (2004) "The solubility of neon, nitrogen, and argon in distilled water and seawater" Deep-Sea Research I: 51(11):1517-1528.	percent	no_bcodmo_term
Krsat	Saturation anomaly of Kr in percent. 0% indicates that the Kr concentration is equal to that expected at equilibrium for the potential temperature and salinity of the water. ie. Krsat = (Kr/Kreq - 1) *100 Kr saturation anomaly is calculated relative to the solubility curve of Weiss and Kyser (1978) "Solubility of Krypton in Water and Seawater" Journal of Chemical Thermodynamics 23(1):69-72.	percent	no_bcodmo_term
N2Arsat	Saturation anomaly of N2/Ar ratio in percent. N2/Ar ratio determined by mass spectrometry divided by the equilibrium ratio for the potential temperature and salinity of the water - 1 * 100; ie. N2Arsat = ((N2/Ar) / (N2eq/Areq) - 1) * 100. N2/Ar saturation anomaly is calculated relative to the solubility curves of Hamme and Emerson (2004) "The solubility of neon, nitrogen, and argon in distilled water and seawater" Deep-Sea Research I: 51(11):1517-1528.	percent	no_bcodmo_term
N2Arsat_UW	Same as for N2Arsat but for data analyzed at University of Washington.	percent	no_bcodmo_term
ptmp	Potential temperature in oC and referenced to the surface.	degrees Celsius	potemp
press	Pressure	decibars	press
CTDsal	salinity measured by the CTD (AR7W cruises: finalized CTD data is an average of downcasts and upcasts within 10dbar of the pressure where the niskin bottle closed; GEOTRACES cruise: finalized CTD data from rosette bottle file); expressed on the PSS-78 scale.	unitless	sal
sigma_theta	Potential density of the seawater expressed in sigma units and referenced to the surface.	kilograms per meter cubed - 1000	sigma_theta
water_mass	Water mass for each sample identified using potential temperature and salinity data. 1 = LSW (Labrador Sea Water); 2 = IC (Irminger Current); 3 = ISW (Icelandic Slope Water); 4 = NEADW (NorthEast Atlantic Deep Water); 5 = DSOW (Denmark Strait Overflow Water); 6 = transitional water masses.	unitless	site_descrip
CTDtemp	in situ temperature measured by the CTD (AR7W cruises: finalized CTD data is an average of downcasts and upcasts within 10dbar of the pressure where the niskin bottle closed;GEOTRACES cruise: finalized CTD data from rosette bottle file) in oC on the ITS-90 Temperature Scale.	degrees Celsius	temp
year	year of sample collection	unitless	year

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Dataset: LabSea_Hamme et al 2017