Ice Thickness and Bed Topography Data from Kamelryggen and Verbljud Ice Rises
Dronning Maud Land, Antarctica

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OVERVIEW
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This dataset provides ice thickness and bed elevation data derived from deep-
sounding radar measurements collected during the austral summer of 2021-22 over
Kamelryggen (KAM) and Verbljud (VER) ice rises. The data includes both along-
profile measurements and gridded interpolations.

Goel et al., 2025 (in review for The Cryosphere)
https://egusphere.copernicus.org/preprints/2025/egusphere-2025-2037/

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DATASET CONTENTS
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Files:
  KAM_BED.mat (Kamelryggen - MATLAB format)
  VER_BED.mat (Verbljud - MATLAB format)
  KAM_BED_profile.csv (Kamelryggen along-profile data)
  VER_BED_profile.csv (Verbljud along-profile data)
  KAM_BED_gridded.nc (Kamelryggen gridded data - NetCDF format)
  VER_BED_gridded.nc (Verbljud gridded data - NetCDF format)

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METHODOLOGY
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Ice thickness was calculated from two-way travel time measured by the deep-
sounding radar (2 MHz) using a radio-wave propagation speed of 169 m/μs. Firn
correction (7-10 m) was applied to account for faster radar wave propagation in
the firn layer. The correction was estimated using a steady-state firn density
model (Herron and Langway, 1980) constrained by firn core density data and
surface mass balance. The speed-density relation by Kovacs et al. (1995) was
used to calculate the correction from density profiles. Surface elevation was
measured using GNSS precise-point positioning. Bed elevation was calculated by
subtracting firn-corrected ice thickness from surface elevation. Gridded data
products were generated using bilinear interpolation.

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DATA FORMAT
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MATLAB FORMAT (.mat files):

Each .mat file contains a structure variable 'BED' with the following fields:

ALONG-PROFILE DATA:
Field       Dimensions   Description
---------   -----------  -----------------------------------------------------
x           N x 1        Easting (meters, EPSG:3031)
y           N x 1        Northing (meters, EPSG:3031)
z           N x 1        Surface elevation (meters above WGS84 ellipsoid)
twt         N x 1        Two-way travel time from surface to bed (seconds)
IT          N x 1        Ice thickness (meters)
ele         N x 1        Bed elevation (meters above WGS84 ellipsoid)
IT_fc       N x 1        Firn-corrected ice thickness (meters)
firn_corr   N x 1        Firn correction applied (meters)

GRIDDED DATA:
Field       Dimensions   Description
---------   -----------  -----------------------------------------------------
XX          M x P        Gridded x-coordinates (meters, EPSG:3031)
YY          M x P        Gridded y-coordinates (meters, EPSG:3031)
BB          M x P        Gridded bed elevation (meters above WGS84 ellipsoid)
TT          M x P        Gridded ice thickness (meters)

CSV FORMAT (*_profile.csv files):

Contains along-profile data with the following columns:
  x_m, y_m, z_m, twt_s, ice_thickness_m, bed_elevation_m,
  ice_thickness_firn_corrected_m, firn_correction_m

NETCDF FORMAT (*_gridded.nc files):

Contains gridded data with the following variables:
  x: easting (meters, EPSG:3031)
  y: northing (meters, EPSG:3031)
  bed_elevation: bed elevation (meters above WGS84 ellipsoid)
  ice_thickness: ice thickness (meters)

NetCDF files follow CF-1.8 conventions and include full metadata.

Note: EPSG:3031 = Polar Stereographic projection parallel to 71°S

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RELATED DATASETS
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Source data:
- Deep Radar (2 MHz) - Two-way travel time measurements
- GNSS - Surface elevation
- Surface Mass Balance - Used for firn correction
- Firn cores - Density profiles for firn correction

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ACKNOWLEDGMENTS
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This work was funded by the Ministry of Earth
Sciences (MoES), Government of India and the Research Council of Norway.
Logistical support: Maitri station and Troll station.
