Dataset: GT10-11 - Th234 Particulate
Deployment: KN199-04

Particulate Thorium-234 from in situ pumps.

Principal Investigator:

Kenneth O. Buesseler (Woods Hole Oceanographic Institution, WHOI)

Contact:

Stephanie Owens (Woods Hole Oceanographic Institution, WHOI)

BCO-DMO Data Manager:

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

Project:

U.S. GEOTRACES North Atlantic Transect (GA03) (U.S. GEOTRACES NAT)

Current State:

Final no updates expected

Version:

31 Dec 2012

Deployment Synonyms:

GA03, GT10, USGT-NAT-2010, KN199-4, GNAT, U.S. GEOTRACES NAZT Leg 1, knorr199-4/5, Section Cruise (GA03), 316N20101015

Version Date:

2013-03-06

Data URL:

https://www.bco-dmo.org/dataset-deployment/455689/data

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Description

Particulate Th-234 from in situ pumps, including large size fraction (> 51 um) and small size fraction (1-51 um), from the 2010 and 2011 U.S. GEOTRACES cruises.

Methods & Sampling

Dataset acquisition description

Particulate material was collected using in situ McLane pumps (also see data from Charette and Lam groups). All data were decay corrected back to the mid-pump times.

1-51 um Th-234
On KN199-4, the mesh screens were cut in half and the material from one half was rinsed onto a silver filter and dried down. On KN 204-01a and KN 204-01b, the whole mesh screen was rinsed onto a silver filter and dried down. The mean volume pumped through the whole Supor mesh screens was 475 L.

>51 um Th-234
Whole QMAs, located below a mesh screen in the filter head housing, were oven-dried upon recovery. A 25 mm subsample was taken from this whole filter for beta counting for Th-234. The mean effective volume for the 25 mm QMA subsample was 47 L.

Data Processing Description

Dataset Processing Description

Data were flagged with quality indicators: 1 = Good; 2 = Questionable; 3 = Bad.

BCO-DMO made the following modifications:
- Parameter names have been modified to conform with BCO-DMO naming conventions.
- 'NaN' was replaced with 'nd' to indicate 'no data'.
- cruise_part was separated from the official cruise ID for cruise KN204-01.
- Added ISO_DateTime_UTC from the original date and time fields provided for each cast/event.

Additional GEOTRACES Processing:
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.

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.

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 deployment

Funding

Award Number	Funding Source
OCE-0925158	NSF Division of Ocean Sciences

Instruments

McLane Pump

Supplied Description:

Particulate material was collected using in situ McLane pumps.

Instrument Type

Generic Name: McLane Pump

Generic Description:

McLane pumps sample large volumes of seawater at depth. They are attached to a wire and lowered to different depths in the ocean. As the water is pumped through the filter, particles suspended in the ocean are collected on the filters. The pumps are then retrieved and the contents of the filters are analyzed in a lab.

Parameters

Supplied Name	Supplied description	Supplied Units	Standard Name
cruise_id	Official cruise identifier e.g. KN199-04 = R/V Knorr cruise number 199-04.	text	cruise_id
cruise_part	Part of cruise. For KN204-01: A = 11/6/2011 to 11/18/2011 (Woods Hole to Bermuda) B = 11/19/2011 to 12/11/2011 (Bermuda to Praia, Cabo Verde)	text	cruise_part
station_GEOTRC	GEOTRACES station number; ranges from 1 through 12 for KN199-04 and 1 through 24 for KN204-01. Stations 7 and 9 were skipped on KN204-01. PI-supplied values were identical to those in the intermediate US GEOTRACES master file. Originally submitted as 'Station', this parameter name has been changed to conform to BCO-DMO's GEOTRACES naming conventions.	unitless	station
lat	Latitude. Positive = North.	decimal degrees	lat
lon	Longitude. Negative = West.	decimal degrees	lon
event_GEOTRC	Unique identifying number for US GEOTRACES sampling events; ranges from 2001 to 2225 for KN199-04 events and from 3001 to 3282 for KN204-01 events. PI-supplied values were identical to those in the intermediate US GEOTRACES master file. Originally submitted as 'Event #', this parameter name has been changed to conform to BCO-DMO's GEOTRACES naming conventions.	unitless	event
cast_GEOTRC	Cast identifier, numbered consecutively within a station. PI-supplied values were identical to those in the intermediate US GEOTRACES master file. Originally submitted as 'Cast', this parameter name has been changed to conform to BCO-DMO's GEOTRACES naming conventions.	unitless	cast
month_gmt	2-digit month of year (GMT). in the format mm (01 to 12)	unitless	month_gmt
day_gmt	2-digit day of month (GMT). in the format dd (01 to 31)	unitless	day_gmt
year	4-digit year. in the format YYYY	unitless	year
time_gmt	Time (GMT); 24-hour clock. in the format HHMM	unitless	time_gmt
pump	Pump number.	unitless	no_bcodmo_term
sample_GEOTRC	Unique identifying number for US GEOTRACES samples; ranges from 5033 to 6078 for KN199-04 and from 6112 to 8148 for KN204-01. PI-supplied values were identical to those in the intermediate US GEOTRACES master file. Originally submitted as 'Geotraces #', this parameter name has been changed to conform to BCO-DMO's GEOTRACES naming conventions.	unitless	sample
depth_n	Nominal sample depth.	meters	depth_n
depth	Actual sample depth; provided in original data submission.	meters	depth
Th234_p_1to51	Particulate Thorium-234 from QMA filters. Particle size of 1 to 51 um. Data were decay corrected back to mid-pump times.	dpm/Liter	Th234_part
Th234_p_1to51_unc	Th234_p_1to51 uncertainty.	dpm/Liter	no_bcodmo_term
Th234_p_gt51	Particulate Thorium-234 from mesh screens, filtered onto silver filters. Particle size greater than 51 um. Data were decay corrected back to mid-pump times.	dpm/Liter	Th234_part
Th234_p_gt51_unc	Th234_p_gt51 uncertainty.	dpm/Liter	no_bcodmo_term
q_flag	Quality flag: 1 = Good 2 = Questionable 3 = Bad	unitless	q_flag
ISO_DateTime_UTC	Cast date/time (UTC) formatted to ISO8601 standard. T indicates start of time string; Z indicates UTC. Calculated from original date and time fields.	yyyy-MM-dd'T'HH:mm:ss.SS'Z'	ISO_DateTime_UTC
depth_GEOTRC_CTD	Observation/sample depth in meters, calculated from CTD pressure. Values were added from the intermediate US GEOTRACES master file (see Processing Description).	meters	depth
sample_bottle_GEOTRC	Unique identification numbers given to samples taken from bottles; ranges from 1 to 24; often used synonymously with bottle number. Values were added from the intermediate US GEOTRACES master file (see Processing Description).	unitless	bot_Nis
bottle_GEOTRC	Alphanumeric characters identifying bottle type (e.g., NIS representing Niskin and GF representing GOFLO) and position on a CTD rosette. Values were added from the intermediate US GEOTRACES master file (see Processing Description).	unitless	bottle
BTL_ISO_DateTime_UTC	Date and time (UTC) variable recorded at the bottle sampling time in ISO compliant format. Values were added from the intermediate US GEOTRACES master file (see Processing Description). This standard is based on ISO 8601:2004(E) and takes on the following form: 2009-08-30T14:05:00[.xx]Z (UTC time)	unitless	ISO_DateTime_UTC

Database

Contribute Data

Dataset: GT10-11 - Th234 Particulate
Deployment: KN199-04

Dataset acquisition description

Dataset Processing Description

Database

Contribute Data

Dataset: GT10-11 - Th234 ParticulateDeployment: KN199-04

Dataset acquisition description

Dataset Processing Description

Dataset: GT10-11 - Th234 Particulate
Deployment: KN199-04