A sea-ice thickness retrieval model for 1.4 GHz radiometry and application to airborne measurements over low salinity sea-ice 1Institute of Oceanography, University of Hamburg, Bundesstraße 53, 20146 Hamburg, Germany
13 Dec 2010
2Department of Earth & Atmospheric Sciences, University of Alberta Edmonton, Alberta T6G 2E3, Canada
3Alfred Wegener Institute for Polar and Marine Research, Bussestr. 24, 27570 Bremerhaven, Germany
4Institute of Environmental Physics, University of Bremen, P.O. Box 330440, Germany
5Center for Ocean & Ice, Danish Meteorological Institute, Lyngbyvej 100, 2100 Copenhagen, Denmark
Received: 19 October 2009 – Published in The Cryosphere Discuss.: 18 November 2009 Abstract. In preparation for the European Space Agency's (ESA) Soil Moisture
and Ocean Salinity (SMOS) mission, we investigated the potential of
L-band (1.4 GHz) radiometry to measure sea-ice thickness.
Revised: 07 June 2010 – Accepted: 24 November 2010 – Published: 13 December 2010
Sea-ice brightness temperature was measured at 1.4 GHz and ice
thickness was measured along nearly coincident flight tracks during
the SMOS Sea-Ice campaign in the Bay of Bothnia in March 2007. A
research aircraft was equipped with the L-band Radiometer EMIRAD and
coordinated with helicopter based electromagnetic induction (EM) ice
We developed a three layer (ocean-ice-atmosphere) dielectric slab model for
the calculation of ice thickness from brightness temperature. The dielectric
properties depend on the relative brine volume which is a function of the
bulk ice salinity and temperature.
The model calculations suggest a thickness sensitivity of up to
1.5 m for low-salinity (multi-year or brackish) sea-ice. For Arctic
first year ice the modelled thickness sensitivity is less than half
a meter. It reduces to a few centimeters for temperatures
approaching the melting point.
The campaign was conducted under unfavorable melting conditions and
the spatial overlap between the L-band and EM-measurements was
relatively small. Despite these disadvantageous conditions we
demonstrate the possibility to measure the sea-ice thickness with
the certain limitation up to 1.5 m.
The ice thickness derived from SMOS measurements would be
complementary to ESA's CryoSat-2 mission in terms of the error
characteristics and the spatiotemporal coverage. The relative error
for the SMOS ice thickness retrieval is expected to be not less than
Citation: Kaleschke, L., Maaß, N., Haas, C., Hendricks, S., Heygster, G., and Tonboe, R. T.: A sea-ice thickness retrieval model for 1.4 GHz radiometry and application to airborne measurements over low salinity sea-ice, The Cryosphere, 4, 583-592, doi:10.5194/tc-4-583-2010, 2010.