Processed bed elevation picks from airborne radar depth sounding from the FISS 2016 survey covering the Filchner and Halley Ice Shelves (2016/2017)

This dataset contains bed and surface elevation picks derived from airborne radar collected in 2016/17 over the Filchner Ice Shelf and Halley Ice Shelf (West Antarctica) as part of the 5-year Filchner Ice Shelf System (FISS) project funded by NERC (grant reference number: NE/L013770/1) and awarded to the British Antarctic Survey with contribution from the National Oceanography Centre, the Met Office Hadley Centre, University College London, the University of Exeter, Oxford University, and the Alfred Wenger Institute.

The aim of this project was to investigate how the Filchner Ice Shelf might respond to a warmer world, and what the impact of sea-level rise could be by the middle of this century. This collaborative initiative collected ~15,000 line-km of new aerogeophysical data using the 150MHz PASIN radar echo sounding system (Corr et al., 2007) deployed on a British Antarctic Survey (BAS) Twin Otter.

The majority of flights were flown as part of FISS over the Support Force, Recovery, Slessor, and Bailey ice streams. Separate flights over Halley 6 research station and Brunt Ice Shelf were also collected as part of this season. The bed and surface elevation picks for the English Coast part of this season are available at: https://doi.org/10.5285/e07d62bf-d58c-4187-a019-59be998939cc.

Date (Creation): 2021-10-12

Date (Revision): 2021-10-12

Date (Publication): 2021-10-12

Date (released): 2021-10-12

Edition: 1.0

Unique resource identifier: https://doi.org/10.5285/e7851bba-21ff-4645-b557-d8eafdf89462

Codespace: doi

Unique resource identifier: GB/NERC/BAS/PDC/01573

Codespace: https://data.bas.ac.uk/

Unique resource identifier: NE/L013770/1

Codespace: award

Other citation details: Please cite this item as: Corr, H., Robinson, C., Jordan, T., Nicholls, K., & Brisbourne, A. (2021). Processed bed elevation picks from airborne radar depth sounding from the FISS 2016 survey covering the Filchner and Halley Ice Shelves (2016/2017) (Version 1.0) [Data set]. NERC EDS UK Polar Data Centre. https://doi.org/10.5285/e7851bba-21ff-4645-b557-d8eafdf89462

Credit: No credit.

Status: Completed

Point of contact

Organisation name	Individual name	Electronic mail address	Role
British Antarctic Survey	Corr, Hugh		Author
British Antarctic Survey	Robinson, Carl		Author
British Antarctic Survey	Jordan, Tom		Author
British Antarctic Survey	Nicholls, Keith		Author
British Antarctic Survey	Brisbourne, Alex		Author
NERC EDS UK Polar Data Centre		PDCServiceDesk@bas.ac.uk	Point of contact

Maintenance and update frequency: As needed

Maintenance note: Completed

Global Change Master Directory (GCMD) Science Keywords

Theme

Antarctic
aerogeophysics
ice thickness
radar
surface elevation

Place

Filchner Ice Shelf Antarctica
Halley Ice Shelf Antarctica

GEMET - INSPIRE themes, version 1.0

Elevation

Access constraints: Other restrictions

Other constraints: no limitations to public access

Access constraints: Other restrictions

Other constraints: no limitations

Use constraints: License

Other constraints: Open Government Licence v3.0

Use constraints: Other restrictions

Other constraints: This data is governed by the NERC Data Policy: https://www.ukri.org/who-we-are/nerc/our-policies-and-standards/nerc-data-policy/

Use constraints: Other restrictions

Other constraints: Further by downloading this data the user acknowledges that they agree with the NERC data policy (), and the following conditions:

1. To cite the data in any publication as follows:

Corr, H., Robinson, C., Jordan, T., Nicholls, K., & Brisbourne, A. (2021). Processed bed elevation picks from airborne radar depth sounding from the FISS 2016 survey covering the Filchner and Halley Ice Shelves (2016/2017) (Version 1.0) [Data set]. NERC EDS UK Polar Data Centre. https://doi.org/10.5285/E7851BBA-21FF-4645-B557-D8EAFDF89462

2. The user recognizes the limitations of data. Use of the data is at the users' own risk, and there is no warranty as to the quality or accuracy of any data, or the fitness of the data for your intended use. The data are not necessarily fully quality assured and cannot be expected to be free from measurement uncertainty, systematic biases, or errors of interpretation or analysis, and may include inaccuracies in error margins quoted with the data.

Use constraints: Other restrictions

Other constraints: None

Unique resource identifier: url

Codespace: url

Association Type: Larger work citation

Unique resource identifier: doi

Codespace: doi

Association Type: Cross reference

Unique resource identifier: doi

Codespace: doi

Association Type: Cross reference

Unique resource identifier: url

Codespace: url

Association Type: Cross reference

Unique resource identifier: doi

Codespace: doi

Association Type: Cross reference

Spatial representation type: Text, table

Language: English

Character set: UTF8

Topic category

Elevation
Geoscientific information

Begin date: 2016-12-15

End date: 2017-01-19

Supplemental Information: It is recommended that careful attention be paid to the contents of any data, and that the author be contacted with any questions regarding appropriate use. If you find any errors or omissions, please report them to polardatacentre@bas.ac.uk.

Title: European Petroleum Survey Group (EPSG) Geodetic Parameter Registry

Date (Publication): 2008-11-12

Cited responsible party

Organisation name	Individual name	Electronic mail address	Role
European Petroleum Survey Group		EPSGadministrator@iogp.org	Publisher

Unique resource identifier: urn:ogc:def:crs:EPSG::3031

Version: 6.18.3

Distributor

Distributor contact

Organisation name	Individual name	Electronic mail address	Role
NERC EDS UK Polar Data Centre		PDCServiceDesk@bas.ac.uk	Distributor

Distributor format

Name	Version
text/csv

Units of distribution: bytes

Transfer size: 308281344

OnLine resource

Protocol	Linkage	Name
WWW:LINK-1.0-http--link	https://ramadda.data.bas.ac.uk/repository/entry/show?entryid=e7851bba-21ff-4645-b557-d8eafdf89462	Get Data

Hierarchy level: Dataset

Statement: Methodology:

Radar data were collected using the new bistatic PASIN-2 radar echo sounding system mounted on the BAS Twin Otter aircraft "VP-FBL" and operating with a centre frequency of 150 MHz and using a 4-microseconds, 13 MHz bandwidth linear chirp. Data provided here includes picks and derived elevations of the ice sheet surface and bed.

The radar data was processed using a coherent averaging filter (commonly referred to as unfocused Synthetic Aperture Radar (SAR) processing) with Doppler beam sharpening to enhance the signal to clutter ratio of the bed echo and improve visualisation. The received chirp of 4 microseconds, 13 MHz bandwidth data was compressed, filtered, and decimated from the original trace acquisition rate of 156.25 Hz to 5Hz, equivalent to ~11m in along-track spacing.

The bed reflector was first automatically depicted on the chirp data using a semi-automatic picker in the PROMAX software package. All the picks were afterwards checked and corrected by hand if necessary. The picked travel time was then converted to depth using a radar wave speed of 168 m/microseconds and a constant firn correction of 10 m. Where possible, the ice surface location within the radargrams was calculated using lidar measurements of surface elevation. In areas where lidar data was not available, the location of the surface reflection was picked directly from the radargram. The origin of the elevation measurement can be found in the 'Surface_Source' header in the CSV, and is composed of either: 0 = LIDAR, 1 = interpolated LIDAR for gaps ~55 m, 2 = radar.

Positions are calculated for the phase centre of the aircraft antenna. All positions (Longitude, Latitude and Height) are referred to the WGS1984 ellipsoid. Longitude and Latitude are provided in WGS84 (EPSG 4326).

DATA FORMAT:

The dataset includes an intermediate processing product (in .csv), with attributes as follows:

Line_ID: Flight name e.g. F02

Trace: Radar segy file trace number

Longitude_decimal_degrees: Longitude in decimal degrees (WGS84 EPSG:4326)

Latitude_decimal_degrees: Latitude in decimal degrees (WGS84 EPSG:4326)

DateTime_YYYY-MM-DD_HH:MM:SS.SSS: Date (YYYY/MM/DD) and Time UTC (HH:MM:SS.SSS) of trace separated by 'T'

Surface_elevation_WGS84_m: Surface Elevation (m) relative to WGS84 Ellipsoid

Ice_thickness_m: Ice thickness (m) calculated for a radar velocity in ice of 168 microseconds and applying a 10-m firn

Bed_elevation_WGS84_m: Bedrock Elevation (m) relative to WGS84 Ellipsoid

PriNumber: Radar counter in segy header (arbitrary units)

Surface_pick: Location down trace of surface pick

Bed_pick: Location down trace of bed elevation pick

Surface_Source: Source of elevation measurements 0 = lidar, 1 = interpolated lidar for gaps ~ 55 m, 2 = from ice sounding radar

Aircraft_elevation_WGS84_m: Elevation (m) of aircraft IMU relative to WGS84 Ellipsoid

Campaign_name: Name of the campaign

Owner: Owner of the data

Funding: Funding provider and grant number

Note: missing data values where no surface/bed pick/elevation exist are reported as '-9999'.

Data collection:

Radar data were collected using the new bistatic PASIN-2 radar echo sounding system

operating with a centre frequency of 150 MHz and using a 4-microseconds, 13 MHz bandwidth linear chirp.

Data quality:

- Average spacing between radar traces: 11 m

- Radar centre frequency: 150 MHz

- Radar bandwidth: 13 MHz

- Radar Receiver vertical sampling frequency: 22 MHz

- Absolute GPS positional accuracy: ~0.1 m (relative accuracy is one order of magnitude better). Banking angle was limited to 10 degrees during aircraft turns to avoid phase issues between GPS receiver and transmitter.

Metadata

File identifier: e7851bba-21ff-4645-b557-d8eafdf89462 XML

Metadata language: English

Character set: UTF8

Hierarchy level: Dataset

Hierarchy level name: dataset

Date stamp: 2021-10-12

Metadata standard name: ISO 19115 Geographic Information - Metadata

Metadata standard version: ISO 19115:2003(E)

Metadata author

Organisation name	Individual name	Electronic mail address	Role
NERC EDS UK Polar Data Centre		polardatacentre@bas.ac.uk	Point of contact

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