Variations of sea ice extent in the Caspian and Aral seas derived from combination of active and passive satellite microwave data

The paper discusses time and space variations of ice cover in the Caspian and Aral seas. We use the synergy of data from active (radar altimeter) and passive (radiometer) microwave instruments onboard the TOPEX/Poseidon satellite, as well as passive microwave data from SSMR and SSM/I sensors. The results indicate significant spatial and temporal variability of ice conditions, with a marked decrease of both duration of ice season and ice extent during winters 1998/99-2001/02. The satellite-derived time series of sea ice parameters are very valuable in view of the heterogeneous and mostly unpublished data on ice conditions over the Caspian and Aral seas since the mid-1980s.