Dataset: Atmospheric pO2 data

Name: SOS-Argo floats: atmospheric pO2 data acquired in different ocean basins between May 2012 and July 2023
Published: 2023-02-08
Keywords: oceans

Cite This Dataset

DOI:10.26008/1912/bco-dmo.915289.1

Spatial Extent: N:52.558 E:180 S:-59.214 W:-179.99

Temporal Extent: 2012-05-31 - 2023-07-13

Project:

The Biological Pump in the Eastern Equatorial Pacific: in situ measurements of Oxygen and Nitrate (Biological Pump in the Equatorial Pacific)

Principal Investigator:

Steven R. Emerson (University of Washington, UW)

Contact:

Steven R. Emerson (University of Washington, UW)

Technician:

Jonah Dirks (University of Washington, UW)

BCO-DMO Data Manager:

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

Version:

Version Date:

2023-02-08

Restricted:

Validated:

Yes

Current State:

Final no updates expected

SOS-Argo floats: atmospheric pO2 data acquired in different ocean basins between May 2012 and July 2023

Abstract:

This dataset contains data from Argo floats deployed by the Emerson group at the University of Washington between May 2012 and July 2023. The name SOS-Argo stands for “Special Oxygen Sensor Argo” Floats. These floats have standard Argo sensors for hydrostatic pressure, temperature, and salinity in addition to an Aanderaa oxygen sensor (optode) installed on a 61 cm stalk above the end cap of the float. The tall stalk allows the float to make atmospheric pO2 measurements uncontaminated by surface waters while the float is at the surface during data transfer to shore. The atmospheric pO2 data are used for in situ calibration of the O2 sensor against atmospheric pO2.

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Archival Copy

Version Date	Archive	Persistent Identifier (PID)	Date PID Issued
2023-02-08	Marine Biological Laboratory/Woods Hole Oceanographic Institution Library (MBLWHOI DLA)	10.26008/1912/bco-dmo.915289.1	2024-02-08

Description

These data also appear on the University of Washington Google website (see related datasets) along with maps of the float locations and preliminary sections and figures of selected data.
Data archived here are: time, location and the partial pressure of O2.

Methods & Sampling

The floats were deployed in different ocean basins: Northwest, Central and Eastern Pacific, Atlantic, Arabian Sea and Indian Ocean. These floats are standard Argo APEX floats with a variety of sensors in addition to those for pressure, temperature, and salinity.

Most of the data (47 floats that are called SOS-Argo floats) have an Aanderaa pO2 sensor (optode) installed on a 61 cm stalk above the end cap of the float, which allows the float to capture uncontaminated atmospheric pO2 for the purpose of in-situ calibration while the float is at the surface.

In addition to the SOS-Argo floats there are five equatorial floats with sensors for nitrate (NO3) and pH in addition to a pO2 sensor on a stalk that is 10 cm high rather than the 61 cm on the SOS-Argo floats. We refer to these floats as BGC floats (here meaning they carry a NO3 and pH sensor in addition to the standard P,T and S sensors). The numbers of these floats are 8474, 8482, 11017, 12788, 17862 and 18608; and are marked with two asterisks ** on the UW website.

There are an additional six standard Argo floats without a 61 cm optode stalk. The numbers of these floats are 12632, 12780, 12783, 12792, 18827 and 18822; and are marked with a single asterisk * on the UW webpage.

Data Processing Description

Measurements of pO2 in the air when the floats reach the surface were used calibrate the optodes against atmospheric pO2. The procedure for doing this is described in detail in the paper by Bushinski et al., 2016. Briefly, we used a two-stage process in which each optode was calibrated as a function of pO2 and temperature in the Emerson Lab. This procedure resulted in the following polynomial for pO2 as a function of temperature and optode t-phase. The “C” values are presented in "Data Files" under the “Optode calibration table”.

pO2 = (((C(5)*T+C(4))/(C(6)+C(7)*y))-1)/(C(1)+C(2)*T+C(3)*T^2)

where: T is optode temperature (deg C), y is optode t-phase (degrees), “C” values are given in the table below

Laboratory-calibrated oxygen sensors were recalibrated at sea against in situ atmospheric pO2 values calculated from NCEP reanalysis atmospheric pressure, P, and humidity, pH2O, for the float location and sampling time along with the oxygen mole fraction in air (XO2=0.20946).”

pO2 (atm) = XO2 (P – pH2O)

When the SOS-Argo float surfaced the pO2 measurements were made every two minutes for a period of one hour. Profile timing was adjusted so that the float surfaced during night time to avoid heating of the optode foil by direct exposure to the sun. Surface profile pO2 measurements were adjusted to equal the mean of the atmospheric measurements while the float was on the surface.

BCO-DMO Processing

* Merged data of all floats into a single dataset

Data Files

File
915289_v1_sosargo_atmosphericpo2.csv (Comma Separated Values (.csv), 18.30 MB) MD5:a960002b89bf1d28b32450fc46ab9606 Primary data file for dataset ID 915289, version 1

Supplemental Files

File
Optode Calibration File filename: Float_Optodes_coef_table.docx (Microsoft Word document, 23.33 KB) MD5:497e3983cd79f182d3a4b29cfbc4248b

More Information about this dataset

Funding Sources

Funding Source	Award Number
NSF Division of Ocean Sciences	OCE-1737080

Deployments

None available yet

Instruments

drifting subsurface profiling float

Supplied Name: SOS-Argo Float

Supplied Description:

Instrument Type

Generic Name: drifting subsurface profiling float

Generic Description:

An unmanned instrumented platform drifting freely in the water column that periodically makes vertical traverses through the water column (e.g. Argo float).

Parameters

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

Supplied Name	Supplied description	Supplied Units	Standard Name
Float	Float serial number	unitless	sample_descrip
Float_Profile	Float profile number (1, 2, 3…)	unitless	sample_descrip
Matlab_Time	Matlab time (days since Jan 1, year 0000)	unitless	date
Excel_Time	Excel time (days since Jan 1, 1900)	unitless	date
Longitude	Degrees Longitude (east is positive)	decimal degrees	lon
Latitude	Degrees Latitude (north is positive)	decimal degrees	lat
O2_tphase	Oxygen sensor (optode) t-phase (degrees)	degrees	O2
O2_temp	Oxygen sensor (optode) temperature (deg C)	degrees Celsius (C)	O2
Matlab_time_HumanReadable	Matlab time converted to human readable date notation (yyyy-mm-dd). Format: %Y-%m-%d	unitless	no_bcodmo_term
O2_optode	Oxygen (optode) pO2 (atmospheres)	atmospheres (atm)	O2