Dataset: Underway pCO2

Name: Underway pCO2 from the R/V Pelican cruise GOM_UW_1704 conducted in the Northern Gulf of Mexico in April 2017.
Published: 2019-07-01
Keywords: Underway pCO2, Gulf of Mexico, Spring bloom, oceans

Cite This Dataset

DOI:10.1575/1912/bco-dmo.770864.1

Spatial Extent: N:29.6455 E:-88.7984 S:27.4902 W:-93.4223

Temporal Extent: 2017-04-06 - 2017-04-16

Project:

Collaborative Research: pH Dynamics and Interactive Effects of Multiple Processes in a River-Dominated Eutrophic Coastal Ocean (nGOMx acidification)

Principal Investigator:

Wei-Jun Cai (University of Delaware)

Co-Principal Investigator:

Katja Fennel (Dalhousie University)

Nancy Rabalais (Louisiana State University, LSU)

BCO-DMO Data Manager:

Karen Soenen (Woods Hole Oceanographic Institution, WHOI BCO-DMO)

Version:

Version Date:

2019-07-01

Restricted:

Validated:

Yes

Current State:

Final no updates expected

Underway pCO2 from the R/V Pelican cruise GOM_UW_1704 conducted in the Northern Gulf of Mexico in April 2017.

Abstract:

Underway pCO2 from R/V Pelican cruise conducted in the northern Gulf of Mexico (27.5 N, 30 N, 88 W, 94 W) from April 5th to 16th in 2017. The precision of pCO2 is ±2 µatm.

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Archival Copy

Version Date	Archive	Persistent Identifier (PID)	Date PID Issued
2019-07-01	Marine Biological Laboratory/Woods Hole Oceanographic Institution Library (MBLWHOI DLA)	10.1575/1912/bco-dmo.770864.1	2019-07-10

Description

Underway pCO2 from R/V Pelican cruise GOM_UW_1704 conducted in northern Gulf of Mexico in April 2017.

Methods & Sampling

Underway sea surface temperature, salinity, and pCO2 data were collected continuously along the cruise track. Surface seawater was collected from an intake on the port side of the ship at about 4m depth. SST and SSS were measured by an SBE45 (Sea-Bird Electronics) Thermosalino graph installed in the sea chest. Seawater was pumped to the ship's labs. There, underway pCO2 was measured inline by an automated system (Apollo Scitech) with a Li-7000 (LICOR, Inc.) non-dispersive infrared detector at a water flow rate of 3-4L/min; The sampling interval was 2 min. This autonomous system was twice daily against three certified CO2 gas standards (150.62, 404.72, and 992.54 ppm) obtained from NOAA's Earth System Research Laboratory (ESRL), Global Monitoring Division in Boulder, CO. These gas standards are directly traceable to the World Meteorological Organization (WMO) scale. The precision of underway pCO2 measurements of this system is 0.1 μatm, and the overall accuracy is estimated at 2 μatm, as documented by Pierrot et al. (2009). The underway system uses a shower head type equilibrator with ~0.5L headspace volume.

Instruments:
Underway pCO2 was measured inline by an automated system (Apollo Scitech) with a Li-7000 (LICOR, Inc.) non-dispersive infrared detector .

The pCO2 measurement was calibrated twice daily against 3 certified CO2 gas
standards (150.62, 404.72, and 992.54 ppm)

Data Processing Description

1) Read the data into Excel.
2) Get the data log book and delete any questionable data such as those during instrument failure. Note: data during calibration should be cut and pasted into another worksheet.
3) Correct the CO2 data directly from Li-Cor using the calibration results. Specifically, first get the linear relationship between the known xCO2 from gas cylinders and the Li-Cor reading; then use the correlated equation to correct the raw xCO2 to calibrated xCO2.
4) Calculate the surface water pCO2 at the temperature of equilibration (it will be corrected to in-situ temperature later) [pCO2 (eq), units: μatm][Weiss and Price, 1980].
5) Calculate in-situ pCO2 [pCO2@SST, units: μatm] (Takahashi et al. 1993)

Data Manager processing notes:
- Converted longitude range from 0-360 to -180 - 180
- Added "Z" to end the datetime stamp to indicate it was in UTC time

Data Files

File
pco2.csv (Comma Separated Values (.csv), 834.46 KB) MD5:d33c7c7db72ebac5d5a207d179b6b459 Primary data file for dataset ID 770864

More Information about this dataset

Funding Sources

Funding Source	Award Number
NSF Division of Ocean Sciences	OCE-1559279

Deployments

Deployment	Synonyms	Start Date	Platform	Investigator
PE17-18	GOM_UW_1704 GOM_CTD_1704	2017-04-05	R/V Pelican	Baoshan Chen (Chief Scientist)	data info

Instruments

LI-COR LI-7000 Gas Analyzer

Supplied Name: a Li-7000 (LICOR, Inc.) non-dispersive infrared detector

Supplied Description:

Underway pCO2 was measured inline by an automated system (Apollo Scitech) with a Li-7000 (LICOR, Inc.) non-dispersive infrared detector .

Instrument Type

Generic Name: LI-COR LI-7000 Gas Analyzer

Acronym: LI-COR LI-7000

Community Identifier: http://vocab.nerc.ac.uk/collection/L05/current/382/

Generic Description:

The LI-7000 CO2/H2O Gas Analyzer is a high performance, dual cell, differential gas analyzer. It was designed to expand on the capabilities of the LI-6262 CO2/ H2O Gas Analyzer. A dichroic beam splitter at the end of the optical path provides radiation to two separate detectors, one filtered to detect radiation absorption of CO2 and the other to detect absorption by H2O. The two separate detectors measure infrared absorption by CO2 and H2O in the same gas stream. The LI-7000 CO2/ H2O Gas Analyzer is a differential analyzer, in which a known concentration (which can be zero) gas is put in the reference cell, and an unknown gas is put in the sample cell.

pCO2 Sensor

Supplied Name:

Supplied Description:

Underway pCO2 was measured inline by an automated system (Apollo Scitech) with a Li-7000 (LICOR, Inc.) non-dispersive infrared detector .

Instrument Type

Generic Name: pCO2 Sensor

Generic Description:

A sensor that measures the partial pressure of CO2 in water (pCO2)

Sea-Bird SBE 45 MicroTSG Thermosalinograph

Supplied Name: SBE45 (Sea-Bird Electronics) Thermosalino graph

Supplied Description:

Instrument Type

Generic Name: Sea-Bird SBE 45 MicroTSG Thermosalinograph

Acronym: SBE 45 MicroTSG

Community Identifier: http://vocab.nerc.ac.uk/collection/L22/current/TOOL0190/

Generic Description:

A small externally powered, high-accuracy instrument, designed for shipboard determination of sea surface (pumped-water) conductivity and temperature. It is constructed of plastic and titanium to ensure long life with minimum maintenance. It may optionally be interfaced to an external SBE 38 hull temperature sensor.

Sea Bird SBE 45 MicroTSG (Thermosalinograph)

Parameters

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

Supplied Name	Supplied description	Supplied Units	Standard Name
Region	Study area: MisPlume (west), MisPlume (east), AtchCoast or AtchPlume	unitless	region
Cruise	Cruise name	unitless	cruise_name
GPS_DateTime_UTC	Date time in format yyyy-mm-ddTHH:MM:SS (UTC)	unitless	ISO_DateTime_UTC
Longitude	Longitude, west is negative	decimal degrees	lon
Latitude	Latitude, south is negative	decimal degrees	lat
Temperature	Sea surface tempearture, measured with SBE45	degrees Celsius (°C)	temperature
Salinity	Sea surface salinity, measured with SBE45	PSU	sal
pCO2	pCO2 at SST (+-2 uatm)	microatmosphere (uatm)	pCO2
Flag_pCO2	Flag of pCO2 at SST. A flag indicated as 2 is good, it means the precision is less than +- 2 uatm	unitless	flag

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