The Cryosphere Discussions
www.the-cryosphere-discuss.net
1994-0432
1994-0440
3
3
2009
10.5194/tcd-3-995-2009
http://www.the-cryosphere-discuss.net/3/995/2009/
http://www.the-cryosphere-discuss.net/3/995/2009/tcd-3-995-2009.html
http://www.the-cryosphere-discuss.net/3/995/2009/tcd-3-995-2009.pdf
995
1022
2009-11-18
A sea ice thickness retrieval model for 1.4 GHz radiometry and application to airborne measurements over low salinity sea ice
L. Kaleschke
lars.kaleschke@zmaw.de
N. Maaß
C. Haas
S. Hendricks
G. Heygster
R. T. Tonboe
Institute of Oceanography, University of Hamburg, Bundesstraße 53, 20146 Hamburg, Germany
Department of Earth & Atmospheric Sciences, University of Alberta Edmonton,\newline Alberta T6G 2E3, Canada
Alfred Wegener Institute for Polar and Marine Research, Bussestr. 24, 27570 Bremerhaven, Germany
Institute of Environmental Physics, University of Bremen, P.O. Box 330440, Germany
Center for Ocean & Ice, Danish Meteorological Institute, Lyngbyvej 100, 2100 Copenhagen, Denmark
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)
radiometery to measure sea ice thickness.
<br><br>
Sea ice brightness temperature was measured at 1.4 GHz and ice thickness were
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 thickness measurements.
<br><br>
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.
<br><br>
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
modeled thickness sensitivity is roughly half a meter. It reduces to a few
centimeters for temperatures approaching the melting point. Although the
campaign was conducted under such unfavorable melting conditions and despite
limited spatial overlap between the L-band and EM-measurements was small we
demonstrate a large potential for retrieving the ice thickness in the range
of 0.2 to 1.5 m.
<br><br>
Furthermore, we show that the ice thickness derived from SMOS measurements
would be complementary to ESA's CryoSat-2 mission in terms of the error
characteristics and the spatio-temporal coverage.
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