Ice-sounding airborne synthetic aperture radar depth profiles from Recovery Ice Stream 2016/17 and Rutford Ice Stream 2019/20 to test the RGB-Doppler-Decomposition method.

This data set corresponds to data acquired by the British Antarctic Survey (BAS) airborne Synthetic Aperture Radar (SAR) PASIN2 (Polarimetric Airborne Scientific INstrument, mark 2), designed for deep ice sounding and basal 3d-mapping. The data set includes the processed SAR images as depth profiles in the Recovery Ice Stream and Rutford Ice Stream, respectively downstream and upstream of the grounding line, and respectively for the 2016/17 FISS (Filchner Ice Shelf System) and the 2019/20 BEAMISH (Bed Access, Monitoring and Ice Sheet History) projects, both during the Antarctic Summer. With multiple antennas for transmission and reception at 150-MHz central frequency, and an across-track physical array, PASIN2 resolves the ambiguities for distinguishing between scatterers from port and starboard directions; however, in the two SAR images of the current dataset the port/starboard ambiguities are not resolved. On this dataset the user will be able to apply the RGB Doppler Decomposition method in the Doppler domain, interpret the results, and modify the different parameters and colours to contrast the results, all with the outcome of conducting new decompositions according to other datasets and needs. The RGB Spectral Decomposition is a generalised framework to interpret the SAR images: first, the Doppler or range spectral domains are first split into three sub-bandwidths; next, to each of the three a colour of a triplet of colours is assigned; and finally the three are superposed into one single image by the addition of the three colours. If the decomposition is applied on the Doppler spectrum, the new image contains the directional information related to the Doppler frequencies: positive frequencies when the radar approaches the target, near zero frequencies when the relative distance from radar to target is near stationary, and negative when the radar leaves it behind. If the backscattering is characterised by a very broad beamwidth the target will be gray/white, and if by a very narrow beamwidth then the target will be represented by one of the colours of the triplet.

This work has received funding from the NERC grant NE/L013444/1, project: Ice shelves in a warming world: Filchner Ice Shelf System (FISS), Antarctica.

The 2016/17 data were collected as part of the NERC grant NE/L013770/1, project: Ice shelves in a warming world: Filchner Ice Shelf System (FISS), Antarctica.

The 2019/20 data were collected as part of the BAS National Capability contribution to the NERC/NSF International Thwaites Glacier Collaboration (ITGC) program.

Alternate title: Polar Data Centre (PDC) record GB/NERC/BAS/PDC/01766

Date (Publication): 2025-01-16

Citation identifier: http://www.antarctica.ac.uk/dms/metadata.php?id= / GB/NERC/BAS/PDC/01766

Point of contact

Organisation name	Individual name	Electronic mail address	Role
British Antarctic Survey		pdc@bas.ac.uk	Custodian
NERC EDS UK Polar Data Centre	Arenas Pingarron, A., Brisbourne, A., Corr, H., Jordan, T., Robinson, C., Martin, C., Nicholls, K., & Smith, A.	pdc@bas.ac.uk	Originator

Maintenance and update frequency: Unknown

Keywords

NDGO0001

NERC OAI Harvesting

NERC_DDC

GCMD Parameter Valids

EARTH SCIENCE > Cryosphere > Glaciers/Ice Sheets
EARTH SCIENCE > Spectral/Engineering > Radar

BAS Free-text keywords

Antarctic
Recovery Ice Stream
Rutford Ice Stream
Synthetic Aperture Radar
aerogeophysics
ice thickness

Use limitation: This data is covered by a UK Open Government Licence ( http://www.nationalarchives.gov.uk/doc/open-government-licence/version/3/). Further by downloading this data the user acknowledges that they agree with the NERC data policy ( http://www.nerc.ac.uk/research/sites/data/policy.asp), and the following conditions:

1. To cite the data in any publication.

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.

Access constraints: Other restrictions

Other constraints: This data is covered by a UK Open Government Licence ( http://www.nationalarchives.gov.uk/doc/open-government-licence/version/3/). Further by downloading this data the user acknowledges that they agree with the NERC data policy ( http://www.nerc.ac.uk/research/sites/data/policy.asp), and the following conditions:

1. To cite the data in any publication.

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.

Language: English

Topic category

Geoscientific information

Begin date: 2019-12-24

End date: 2019-12-24

Reference system identifier: OGP / urn:ogc:def:crs:EPSG::4326

Distribution format

Distributor contact

Organisation name	Individual name	Electronic mail address	Role
Polar Data Centre - British Antarctic Survey		pdc@bas.ac.uk	Distributor

OnLine resource

Protocol	Linkage	Name
http		GET DATA

Hierarchy level: Dataset

Domain consistency

Measure identification: INSPIRE / Conformity_001

Conformance result

Title: INSPIRE Data Specification on unknown theme Guidelines

Date

Explanation: See the referenced specification

Pass: No

Statement: The image above Recovery Ice Stream (season 2016/17, Flight F11):

- processing level: only to range-processing, thus without SAR (along-track) focussing of any kind;

- sampling of the output (back-projection) grid: 6.48 meters/pixel in range, and 16 milliseconds/pixel (62.5 Hz) in along-track;

- lightspeed in ice: Ci = 168.3751 meters/microsecond;

- spectral bandwidth: Bw = 13 MHz in pulse (range), and Dw = 50 Hz in Doppler (along-track);

- average aircraft speed: V = 60.92 m/s;

- processed along-track beamwidth (antenna aperture): 2 x arcsin(wavelength x (Dw/2) / (2 x V)) = 48.46 degrees in air, and 26.66 degrees in ice after refraction with refractive index 1.78;

- resolution (if without spectrum windowing): Ci/(2 x Bw) = 6.476 meters in range, and incremented with depth in along-track (because no SAR focusing).

The image above Rutford Ice Stream (season 2019/20, Flight T04):

- processing level: SAR focussing by back-projection;

- sampling of the output (back-projection) grid: 6.48 meters/pixel in range, and 16 milliseconds/pixel (62.5 Hz) in along-track;

- lightspeed in ice: Ci = 168.3751 meters/microsecond;

- spectral bandwidth: Bw = 13 MHz in pulse (range), and Dw = 30 Hz in Doppler (along-track);

- average aircraft speed: V = 55.18 m/s;

- processed along-track beamwidth (antenna aperture): 2 x arcsin(wavelength x (Dw/2) / (2 x V)) = 31.55 degrees in air, and 17.57 degrees in ice after refraction with refractive index 1.78;

- resolution (if without spectrum windowing): Ci/(2 x Bw) = 6.476 meters in range, and V/Dw = 1.84 meters in along-track.

The amplitude and relative phase of the antenna patterns in transmission (as an array of 4 antennas) and reception (as 12 single and independent antennas), were assessed with calibration flights above the sea surface. The patterns are assumed as invariant along each session, if the antenna configuration remains.

The transmitted radar pulses are not calibrated, as parameter drifts are not expected to affect the quality.