<div><p><strong>Sampling Description:</strong><br />
Helium isotope, and helium and neon concentrations were measured on samples drawn from Niskin bottles via tygon tubing and stored in crimped 5/8" copper tubing using the technique described by Young and Lupton (Young and Lupton, 1983).</p>
<p><strong>Sample Processing:</strong><br />
The gas samples were quantitatively extracted on shore using a water vapor extraction method into 25 ml aluminosilicate glass ampoules (Lott and Jenkins, 1998).</p>
<p><strong>Sample Analysis:</strong><br />
Helium isotopes, helium and neon concentrations were measured using an automated magnetic sector-QMS system with cryogenic separation methods described elsewhere (Lott, 2001; Lott and Jenkins, 1984, 1998). Helium isotope measurements were made mass spectrometrically referenced to marine air to an accuracy of 0.15% or better, and corrected for instrumental non-linearity (dependence of isotope ratio determination on sample size). Helium and neon concentrations were determined by peak-height manometry against a calibrated marine air standard. Helium was measured to 0.3% and neon was determined to 0.55%. All uncertainties were confirmed by replicate analyses of water samples and standards.</p>
<p><strong>References:</strong><br /><strong>Lott,</strong> D.E., 2001. Improvements in noble gas separation methodology: a nude cryogenic trap. Geochemistry, Geophysics, Geosystems 2, 10.129/2001GC000202.<br /><strong>Lott</strong>, D.E., Jenkins, W.J., 1984. An automated cryogenic charcoal trap system for helium isotope mass spectrometry. Review of Scientific Instruments 55, 1982-1988. doi: <a href="https://dx.doi.org/10.1063/1.1137692" target="_blank">10.1063/1.1137692</a><br /><strong>Lott</strong>, D.E., Jenkins, W.J., 1998. Advances in the analysis and shipboard processing of tritium and helium samples. International WOCE Newsletter 30, 27-30.<br /><strong>Weiss</strong>, R.F., 1971. Solubility of helium and neon in water and seawater. Journal of Chemical Engineering Data 16, 235-241.<br /><strong>Young,</strong> C., Lupton, J.E., 1983. An ultratight fluid sampling system using cold-welded copper tubing. EOS Transactions AGU 64, 735.</p></div>
Helium and Neon duplicates from station 1 of KN199-04 (GT10) cruise.
<div><p>Helium and Neon concentration duplicates from station 1 of KN199-04 (GT10) cruise. Station, cast, and Niskin bottle numbers are provided along with CTD pressure.</p>
<p>
Please note that some US GEOTRACES data may not be final, pending intercalibration results and further analysis. If you are interested in following changes to US GEOTRACES NAT data, there is an RSS feed available via the BCO-DMO <a href="http://www.bco-dmo.org/project/2066">US GEOTRACES project page</a> (scroll down and expand the "Datasets" section).</p></div>
GT10 - HeNe_dups
<div><p>Parameter names were modified to conform with BCO-DMO naming conventions.</p>
<p>lat_nom and lon_nom were added by BCO-DMO from station waypoints provided by the Chief Scientist of cruise KN199-04.</p>
<p><strong>Additional GEOTRACES Processing:</strong><br />
After the data were submitted to the International Data Management Office, BODC, the office noticed that important identifying information was missing in many datasets. With the agreement of BODC and the US GEOTRACES lead PIs, 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: station_GEOTRC, cast_GEOTRC (bottle and pump data only), event_GEOTRC, sample_GEOTRC, sample_bottle_GEOTRC (bottle data only), bottle_GEOTRC (bottle data only), depth_GEOTRC_CTD (bottle data only), depth_GEOTRC_CTD_rounded (bottle data only), BTL_ISO_DateTime_UTC (bottle data only), and GeoFish_id (GeoFish data only). This added information will facilitate subsequent analysis and inter comparison of the datasets.</p>
<p>Bottle parameters in the master file were taken from the GT-C_Bottle_GT10, GT-C_Bottle_GT11, ODF_Bottle_GT10, and ODF_Bottle_GT11 datasets. Non-bottle parameters, including those from GeoFish tows, Aerosol sampling, and McLane Pumps, were taken from the Event_Log_GT10 and Event_Log_GT11 datasets. McLane pump cast numbers missing in event logs were taken from the Particulate Th-234 dataset submitted by Ken Buesseler.</p>
<p>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.</p>
<p>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.</p>
<p>See the dataset parameters documentation for a description of which parameters were supplied by the PI and which were added via the join method.</p></div>
3825
GT10 - HeNe_dups
2012-12-28T13:21:54-05:00
2012-12-28T13:21:54-05:00
2023-07-07T16:10:26-04:00
urn:bcodmo:dataset:3825
Helium and Neon duplicates from station 1 of R/V Knorr cruise KN199-04 (GT10) in the Subtropical northern Atlantic Ocean in 2010 (U.S. GEOTRACES NAT project)
false
Jenkins, W. J. (2013) Helium and Neon duplicates from station 1 of R/V Knorr cruise KN199-04 (GT10) in the Subtropical northern Atlantic Ocean in 2010 (U.S. GEOTRACES NAT project). Biological and Chemical Oceanography Data Management Office (BCO-DMO). (Version 20 Dec 2012) Version Date 2013-03-05 [if applicable, indicate subset used]. http://lod.bco-dmo.org/id/dataset/3825 [access date]
true
20 Dec 2012
false
2013-03-05
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