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 both the data and literature reference in any publication as follows:

DATA REFERENCE

Ferraccioli, F., Corr, H., Jordan, T.A., Forsberg, R., Matsuoka, K., Diez, A., Olesen, A.V., Ghidella, M., Zakrajsek, A., Robinson, C., King, O. 2018. Bed, surface elevation and ice thickness measurements derived from Radar acquired during the ICEGRAV-2013 airborne geophysics campaign. Polar Data Centre, British Antarctic Survey, NERC, Cambridge, UK. DOI: 10.5285/6549203d-da8b-4a22-924b-a9e1471ea7f1

LITERATURE REFERENCE

Diez A., K. Matsuoka, F. Ferraccioli, T.A. Jordan, H.F.J. Corr, J. Kohler, A. Olesen, and R. Forsberg (2018), Basal settings control fast ice flow in the Recovery/Slessor/Bailey Region, East Antarctica, Geophys. Res. Lett., 45, doi:10.1002/2017GL076601

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.

Methodology:

For the processing of the data a coherent moving-average filter, commonly referred to as an unfocused SAR, was used. The bed reflector was first automatically picked using 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/µs and a constant firn correction of 10 m. Surface elevation measurements were derived from radar altimeter for ground clearance < 750 m, and the PASIN system for higher altitudes.

The data was collected flying at an average flight velocity of 65 m/s. This resulted in approximately10 m alongtrack spacing of radar traces. The radar lines have a spacing of approximately 27 km. The majority of flights are at a constant elevation, required for coincident collection of gravity data.

Channel description:

Basic Channels Name Description

Date UTC date (YYYY/MM/DD)

Time UTC time (HH:MM:SS.SS)

FlightID Sequential flight number and survey ID e.g. W12

Line_name Line Number e.g. LW200.1

Lon Longitude WGS 1984

Lat Latitude WGS 1984

x x projected meters *

y y projected meters *

Height_WGS1984 Aircraft altitude (meters) in WGS 1984

Radar

segy_name Radar_segy file name

TraceNum Radar segy trace number

PriNum Raw radar time

surfPickLoc Location down trace of surface pick

bedPickLoc Location down trace of bed elevation pick

surfElev Surface elevation (m)

bedElev Ice bed elevation (m)

tIce Ice thickness (m)

* Projected coordinates (x and y) are in Weddell Lambert with two standard parallels defined as follows:

Latitude of false origin: -80

Longitude of false origin: -81

Latitude of 1st standard parallel -82

Latitude of 2nd standard parallel -78

False easting 26501

False northing 1977093

Data collection:

Radar data was collected using the PASIN radar echo sounding system (Corr et al., 2007) using a British Antarctic Survey (BAS) Twin Otter. The radar has a centre frequency of 150 MHz. As signal a 4 microsecond chirp was used with a bandwidth of 10 MHz. The used sampling frequency was 22 MHz.