Dataset: Antarctic ACROBAT data

Name: Water temperature, salinity, and optical properties from an Acrobat towed vehicle from bi-weekly grids conducted at Palmer Station, Antarctica in 2020
Published: 2023-12-01
Keywords: earth science, oceans, ocean temperature, salinity, ocean optics, oceans

Cite This Dataset

DOI:10.26008/1912/bco-dmo.916046.1

Spatial Extent: N:-63.77 E:-64.7354 S:-64.285 W:-64.9104

Temporal Extent: 2020-01-01 - 2020-05-01

Project:

Collaborative Research: Physical Mechanisms Driving Food Web Focusing in Antarctic Biological Hotspots (Project SWARM)

Principal Investigator:

Joshua Kohut (Rutgers University)

Hank Statscewich (University of Alaska Fairbanks, UAF)

Co-Principal Investigator:

Matthew Oliver (University of Delaware)

Student:

Jacquelyn Veatch (Rutgers University)

BCO-DMO Data Manager:

Amber D. York (Woods Hole Oceanographic Institution, WHOI BCO-DMO)

Version:

Version Date:

2023-12-01

Restricted:

Validated:

Yes

Current State:

Final no updates expected

Water temperature, salinity, and optical properties from an Acrobat towed vehicle from bi-weekly grids conducted at Palmer Station, Antarctica in 2020

Abstract:

This data is from a towed instrument called an ACROBAT. The Acrobat is a winged instrument platform that cycles between the surface and 60 m as it is towed behind a ship traveling at speeds of 5 to 8 knots. It is equipped with a SeaBird 49 FastCAT CTD (temperature, conductivity, and pressure) and a Wetlabs EcoPUCK optical sensor (chlorophyll a, colored dissolved organic matter (CDOM), and backscatter). The ACROBAT system has been used to map submesoscale features (fronts, eddies and filaments) and provides a real-time data feed via a faired Kevlar cable to the vehicle operator. The ACROBAT enables adaptive sampling of features of interest and detailed mapping of the upper ocean without aliasing due to tides. Bi-Weekly sampling survey grids were conducted out of Palmer Station through the use of the USAP RHIB platform.

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Archival Copy

Version Date	Archive	Persistent Identifier (PID)	Date PID Issued
2023-12-01	Marine Biological Laboratory/Woods Hole Oceanographic Institution Library (MBLWHOI DLA)	10.26008/1912/bco-dmo.916046.1	2024-10-09

Methods & Sampling

Data from the CTD, EcoPUCK, and GPS were combined and vertical profiles were constructed from dives using MATLAB. Data were written to a .mat file that was then combined with metadata to create a netCDF file.

Location: Ocean waters south of Palmer Station, located between 63 - 62.3 S latitude and 64-65 W longitude in depths less than 60 m.

Deployment information:
Palmer RHIB (small boat) operated by United States Antarctic Program operated during the months of Jan - April, 2020 with Principal Investigators: Jackie Veatch, Hank Statscewich, and Josh Kohut.

Related dataset information:

Danielson, S., & Statscewich, H. (2020). Water temperature, salinity, and optical properties from an Acrobat towed vehicle during cruises for the Northern Gulf of Alaska LTER site, 2018 and 2019(Version 1) [Data set]. Axiom Data Science. https://doi.org/10.24431/RW1K471
* This related dataset was collected during a separate deployment of the same instrument platform. The Gulf of Alaska LTER data collection effort was completed aboard the RV Sikuliaq, a 230' icebreaker, whereas the Palmer Station data published in this BCO-DMO dataset (916046) was conducted on smaller rigid hull inflatable vessels.

Data Processing Description

The CTD data were corrected for thermistor thermal response, time lag due to the physical separation of the temperature and conductivity sensors, and conductivity sensor thermal lag following Johnson et al. [2007]. The EcoPUCK did not have a pressure sensor, so depth was added to the data via interpolation using time stamps generated by the data acquisition computer. Position information was collected from the shipboard GPS system and logged at 1 HZ intervals.

Related software:
* initial release of the ACROBAT code developed by the Dr. Seth Danielson's physical oceanography lab ("isreister/ACROBAT: v1.0.0_UAFOceansACROBAT", doi:10.5281/ZENODO.7768458)

BCO-DMO Processing

* No additional processing performed

Data Files

File

SWARM 2020 ACROBAT data in netCDF format
filename: swarm2020_acrobat.nc

(NetCDF, 15.03 MB)
MD5:3a59a941885ec030949c49620c3a28eb

variables and attributes contained in this file:

netcdf swarm2020_acrobat {
dimensions:
        mtime = 4894 ;
        z = 66 ;
        char = 20 ;
variables:
        double Temperature(mtime, z) ;
        double Salinity(mtime, z) ;
        double Density(mtime, z) ;
        double Chlorophyll_a(mtime, z) ;
        double Backscatter(mtime, z) ;
        double CDOM(mtime, z) ;
        double DiveDirection(mtime) ;
        double mtime(mtime) ;
        double Longitude(mtime) ;
        double Latitude(mtime) ;
        char mtime_readable(char, mtime) ;
}

See detailed parameter information in the supplemental file  "PLDP2020_acrobat_metadata.json"
Note: Date_Time "mtime" and "mtime_readable are in time zone UTC.

Supplemental Files

File
Metadata in json format filename: PLDP2020_acrobat_metadata.json (Plain Text, 9.50 KB) MD5:45a91de8865fff2383410383113851ed Metadata presented in an alternate format in addition to BCO-DMO metadata formats. This .json file is formatted to meet "Conventions": "CF-1.6, ACDD-1.3." Date_Time "mtime" is in time zone UTC.

More Information about this dataset

Funding Sources

Funding Source	Award Number
NSF Office of Polar Programs (formerly NSF PLR)	OPP-1745023

Deployments

None available yet

Instruments

Sea-Bird SBE 49 FastCAT CTD Sensor

Supplied Name:

Supplied Description:

Observational data collected using a Seabird SBE49 FastCAT CTD

Instrument Type

Generic Name: Sea-Bird SBE 49 FastCAT CTD Sensor

Acronym: SBE-49

Generic Description:

The SBE 49 FastCAT is a CTD sensor for use in autonomous platforms. It contains a SBE 3P temperature sensor, a SBE 4C conductivity sensor and a strain-gauge pressure sensor as standard. It can operate in autonomus (16 Hz per sec) or polled mode (transmits each sample). The sensor is depth-rated to 350 m (plastic housing) or 7000 m (titanium housing). Accuracy: +/- 0.002 deg C (temperature), +/- 0.0003 S/m (conductivity), 0.1% of full scale range (pressure).

towed undulating vehicle

Supplied Name: ACROBAT

Supplied Description:

The Acrobat is a winged instrument platform that cycles between the surface and 60 m as it is towed behind a ship traveling at speeds of 5 to 8 knots. It is equipped with a SeaBird 49 FastCAT CTD (temperature, conductivity, and pressure) and a Wetlabs EcoPUCK optical sensor (chlorophyll a, colored dissolved organic matter (CDOM), and backscatter). The ACROBAT system has been used to map submesoscale features (fronts, eddies and filaments) and provides a real-time data feed via a faired Kevlar cable to the vehicle operator. The ACROBAT enables adaptive sampling of features of interest and detailed mapping of the upper ocean without aliasing due to tides.

Instrument Type

Generic Name: towed undulating vehicle

Acronym: TUV

Generic Description:

A towed undulating vehicle is a generic class of instruments. See the data set specific information for a detailed description. These are often prototype instrument packages designed to make very specific measurements.

WETLabs ECO FLBB scattering fluorescence sensor

Supplied Name: Wetlabs three-channel flbbcd EcoPUCK

Supplied Description:

Wetlabs three-channel flbbcd EcoPUCK mounted on an Acrobat vehicle.

Instrument Type

Generic Name: WETLabs ECO FLBB scattering fluorescence sensor

Acronym: WETLabs ECO FLBB

Generic Description:

A dual-optical-sensor that carries a single-wavelength chlorophyll fluorometer (470nm ex/695nm em) and backscattering sensor (700 nm) that measures phytoplankton and particle concentration. It operates by using blue (470nm) and red (700 nm) LEDs that alternately flash. The blue LED stimulates chlorophyll fluorescence in plants while the red light illuminates the total particle field. The backscattering sensor has an in-water centroid angle of 142 degrees and can be calibrated to measure turbidity. The fluorometer can typically measure phytoplankton concentrations in the range 0-30 ug/l, with a sensitivity of 0.015 ug/l. The backscattering sensor can measure within the range 0-3 m-1, with a sensitivity of 0.0015 m-1. The instrument output in the standard version is digital and uses a low power mode and stores data. Other variants are used. The instrument is rated to a depth of 600m as standard, with the options of deeper instruments rated up to 6000m and instruments with bio-wipers, rated to 300 m.

This instrument comes in the following optional models: FLbb(RT), FLbb(RT)D, FLbbB, FLbbS, FLbbBS, FLbb2k. Refer to the datasheet from the manufacturer: https://www.seabird.com/asset-get.download.jsa?id=55460873804

Parameters

None available yet

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Database

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Dataset: Antarctic ACROBAT data