Dataset: GOVARS SG502

Name: Data from GOVARS iRobot Seaglider AUV-SG-502 released into McMurdo Sound, Southern Ross Sea, 2010-2011 (GOVARS project)
Published: 2014-10-08
Keywords: oceans

Cite This Dataset

DOI:10.26008/1912/bco-dmo.532608.1

Spatial Extent: N:-76.3403 E:-179.8902 S:-77.5342 W:164.5883

Temporal Extent: 2010-11-22 - 2011-01-20

Project:

Seasonal Evolution of Chemical and Biological Variability in the Ross Sea (GOVARS)

Principal Investigator:

Walker O. Smith (Virginia Institute of Marine Science, VIMS)

Co-Principal Investigator:

Marjorie A.M. Friedrichs (Virginia Institute of Marine Science, VIMS)

Dr Karen J. Heywood (University of East Anglia, UEA)

Contact:

Walker O. Smith (Virginia Institute of Marine Science, VIMS)

BCO-DMO Data Manager:

Stephen R. Gegg (Woods Hole Oceanographic Institution, WHOI BCO-DMO)

Version:

Version Date:

2014-10-08

Restricted:

Validated:

Current State:

Final no updates expected

Data from GOVARS iRobot Seaglider AUV-SG-502 released into McMurdo Sound, Southern Ross Sea, 2010-2011 (GOVARS project)

Abstract:

Data from GOVARS iRobot Seaglider AUV-SG-502 released into McMurdo Sound, Southern Ross Sea, 2010-2011. Temperature, salinity, oxygen, fluorescence, and optical backscatter data reported in 2-month deployment. Full resolution profiles (surface to 600 m, or near bottom of water column) of temperature, potential temperature, salinity, and dissolved oxygen from Seaglider equipped with CTD, oxygen, and optical sensors. The glider was released into the southern Ross Sea from the fast ice surrounding McMurdo Sound. The Southern Ross Sea, bounded by -77.436° and 169.517E°, and extending to -76.3403° and 180°; the glider made two long transects near the 76.5° line from the eastern side of the Ross Sea polynya to the dateline, and back; recovery was by the NB Palmer.

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Archival Copy

Version Date	Archive	Persistent Identifier (PID)	Date PID Issued
2014-10-08	Marine Biological Laboratory/Woods Hole Oceanographic Institution Library (MBLWHOI DLA)	10.26008/1912/bco-dmo.532608.1	2021-02-08

Description

These results were published in:
Kaufman et al. (2014): peer-reviewed paper describing the project and the physical-biological results.
Smith et al. (2014): peer-reviewed paper describing the results in conjunction with other ongoing projects in the area.
Quest et al. (2015): peer-reviewed paper describing the results of the oxygen dynamics.

All of the above have maps showing the study area and data.

Methods & Sampling

Latitude and longitude (parameter names lat and lon) were measured at the surface and linearly interpolated when the glider was at depth. Parameter name GPS value id indicates measurements while glider was at the surface (value = 1) or interpolated while diving (value = 0). No interpolation or smoothing was performed on other data.

Temperature and salinity (parameter names temp and sal): Temperature and salinity data were calculated using pre deployment calibration coefficients. A first-order lag correction was applied to raw measurements of temperature and conductivity (due to temperature latency). For each dive, out of range measurements and spikes (3 interquartile ranges above or below the median in windows of 15 contiguous measurements) were flagged and replaced with NaNs, which were repopulated by linear interpolation. Data were smoothed with an 11-point median filter. Parameters potemp and sigma_0 were calculated from the smoothed temp and sal datasets.

Dissolved oxygen, O2 (parameter name O2_cal): Oxygen data from the Aanderaa optode were corrected for time lags in oxygen and temperature. The resulting oxygen has an error of ±2 µmol kg-1.

Particulate backscattering coefficients, bbp (parameter names bbp470, bbp700): Backscattering digital counts were converted to at 117° by subtracting factory-provided dark counts and β multiplying by factory calibration scale factors.

Particulate organic carbon (POC) derived from bbp(700) (parameter name POC_bbp): The regression to convert ship downcast bbp at 700 nm to POC is: POC (mg C m-3) = 19607*bbp700 + 17.621; R2 = 0.85, p < 0.01. Because all backscatter sensors were cross calibrated with the ship CTD downcast, this regression was directly applied to glider bbp at 700 nm to compute glider POC.

Chlorophyll fluorescence (parameter names chl_raw): Chlorophyll fluorescence measured by glider ECOPuck BB2F was calibrated with discrete chlorophyll samples taken from calibration profiles. The regression was CHL = (FL -141)*0.00225 (R2 = 0.94, p < 0.01).

Data Processing Description

Data Processing: All data were analyzed for peaks and lost data, and if unexplained values were recorded, replaced by a smoothed average from +/- ten points above and below the spike. Sigma-T values are calculated using standard algorithms.

BCO-DMO Processing Notes
- Generated from original file: "SG502.csv" contributed by Walker Smith

Data Files

File
GOVARS_SG502.csv (Comma Separated Values (.csv), 55.02 MB) MD5:aa4e9d4fa1cac6d22566bc6659672637 Primary data file for dataset ID 532608

More Information about this dataset

Funding Sources

Funding Source	Award Number
NSF Antarctic Sciences	ANT-0838980

Deployments

Deployment	Synonyms	Start Date	Platform	Investigator
AUV-SG-502		2010-11-22	iRobot Seaglider	Walker O. Smith (Principal Investigator)	data info

Instruments

Aanderaa Oxygen Optodes

Supplied Description:

Instrument Type

Generic Name: Aanderaa Oxygen Optodes

Acronym: AOO

Community Identifier: http://vocab.nerc.ac.uk/collection/L05/current/351/

Generic Description:

Aanderaa Oxygen Optodes are instrument for monitoring oxygen in the environment. For instrument information see the Aanderaa Oxygen Optodes Product Brochure.

Druck PDCR 4020 pressure sensor

Supplied Name: Druck PDCR 4020

Supplied Description:

Instrument Type

Generic Name: Druck PDCR 4020 pressure sensor

Acronym: Druck PDCR 4020

Generic Description:

The PDCR 4000 Series provides a complete range of mV output pressure transducers offering advanced levels of measurement accuracy stability and flexibility from a standard production device.

Seaglider

Supplied Description:

Instrument Type

Generic Name: Seaglider

Generic Description:

The Seaglider is an autonomous underwater vehicle developed through a collaboration between The Applied Physics Laboratory -University of Washington and the University of Washington School of Oceanography. These small, free-swimming vehicles can gather conductivity-temperature-depth (CTD) data from the ocean for months at a time and transmit it to shore in near-real time via satellite data telemetry. Seagliders make oceanographic measurements traditionally collected by research vessels or moored instruments. They can survey along a transect, profile at a fixed location, and can be commanded to alter their sampling strategies throughout a mission.

Wet Labs ECO Puck BB2F-VMG

Supplied Description:

Instrument Type

Generic Name: Wet Labs ECO Puck BB2F-VMG

Acronym: ECO Puck BB2F-VMG

Generic Description:

The ECO BB measures scattering at 117 degrees, the angle determined as a minimum convergence point for variations in the volume scattering function (VSF) induced by suspended materials and water itself. As a result, the signal measured by this meter is less determined by the type and size of the materials in the water and is more directly correlated to the concentration of the materials. Conversely, the meter provides unparalleled accuracy for any single-angle measurement in determining the optical backscattering coefficient: an important parameter for remote sensing and in many in-water bio-optical applications.

Parameters

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

Supplied Name	Supplied description	Supplied Units	Standard Name
dive_id	dive identification number	dimensionless	dive_id
date	date (UTC) start of sampling	YYYYMMDD	date
julian_day_yr0	time when sample was taken in decimal days since Jan-0-0000	dimensionless	julian_day_yr0
lat	latitude (South is negative)	decimal degrees	lat
lon	longitude (West is negative)	decimal degrees	lon
GPS_id	GPS value id; measurement taken while on surface (value=1) or interpolated while diving (value=0)	integer	GPS_id
depth	depth at which sample was taken	meters	depth
temp	Temperature	degrees Celsius	temp
potemp	Potential Temperature	degrees Celsius	potemp
sal	Salinity	dimensionless	sal
sigma_0	potential density minus 1000	kilograms/meter^3	sigma_0
O2_cal	dissolved oxygen concentration measured from Aanderaa Optode 3830 oxygen sensor	micromol/kilogram	O2_cal
POC_bbp	particulate organic carbon from bbp(700); based on POC and bbp(700) measurements	milligrams/meter^3	POC_bbp
bbp470	particulate backscattering coefficient at 470 nm; bbp(470) from ECOPuck BB2F;based on factory calibrations	β(θc) /m /sr	bbp470
bbp700	particulate backscattering coefficient at 700 nm; bbp(700) from ECOPuck BB2F; intercalibrated with KN19303 bbp(700) measurements	(θc) /m /sr	bbp700
chl_raw	chlorophyll fluorescence (raw output minus dark counts)	milligrams/meter^3	chl_raw

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Dataset: GOVARS SG502