THINICE
THIN ICE - Investigation of THIN ICE using dual-polarization, multi-frequency microwave observations
Duration: 06/2008 - 06/2010 (2011)
Involved: Institute of Oceanography, Hamburg; Institute of Environmental Physics, Bremen; Alfred-Wegener Institute for Polar and Marine Research, Bremerhaven
Summary:
The heat exchange through openings in the sea-ice cover (leads, polynyas) can exceed the one over adjacent thick ice by two orders of magnitude during winter. Such openings are sites for maximum ice production and maximum input of solar radiation. This study aims at improving the identification and classification of thin ice, and the estimation of its thickness. Available and future satellite data of the radar signature of sea ice will be analyzed in combination with helicopter-borne measurements of the radar signature of sea ice at different frequencies, polarizations, and incidence angles, and concurrent in-situ observations, both carried out during field campaigns into the polar region. One aspect of this analysis will be the improvement of numerical modeling of the radar signature of thin ice. An existing approach to obtain an estimate of the thickness of thin ice using helicopter-borne data will be reviewed and optimized, and modified to use it for satellite data, considering the results from numerical modeling. The approach will be validated with data from the field campaigns and applied to satellite observation of one winter.
Aims:
I: Which combination (frequency, polarization, incidence angle) of RB data enables to unambiguously separate young ice from open water and other ice types, to differentiate between different thin ice (surface, i.e. bare, snow covered) types (grease ice, nilas), and to use them for thin-ice thickness retrieval?
II: Which is the optimal measurement strategy to obtain a robust and reliable retrieval of thin ice thickness, considering the results obtained for item I, and independent of daylight, cloud cover and auxiliary data?
III: What would be the conclusion of the results of items I and II to use AMSR-E 6.9 GHz channels and SMOS to identify thin ice and derive its thickness?
coordinated by: Prof. Dr. D. Stammer, Remote Sensing & Assimilation Group, Institute of Oceanography, University of Hamburg
Please address questions to Detlef Stammer or Stefan Kern
- Map of the Arctic Ocean sea-ice concentration of Sep. 6 2007 superposed with the cruise track of the R/V polarstern during the Expedition ARKXXII/2; symbols refer to locations where Multi³Scat measurement flights and/or ice station work have been carried out.
- Sample set of time-series of the radar backscatter values measured at approx. 52° incidence angle at X-Band on Sep. 16, 2007, over a patch of light nilas, grey ice embedded in a matrix of second-year / brach ice. The time-series at the top is original temporal resolution (1/16 s), while those at the bottom have been smoothed with a running 1s-long filter.
- Overview about radar backscatter values and ratios obtained over the same patch of thin ice simultaneously at (above) S-, C-, (below) X-, and Ku-Band.
