Ice cover variability in the Caspian and Aral seas from active and passive microwave satellite data

Kouraev et al. 2003: Polar Research 22(1), 43–50 A stable and strong ice cover forms during winter months in the Aral Sea and northern part of the Caspian Sea. The presence of ice cover negatively affects navigation and fi shery condi tions and endangers facilities located on the coast as well as on the shelf, such as oil rigs that have recently been installed in the northern Caspian by Russia and Kazakhstan. Ice conditions in these two seas vary signifi cantly from year to year in response to meteorological changes. Data on ice cover variability may therefore serve as an early indicator of large-scale climate change (Allison et al. 2001). Regular studies of ice cover in the Caspian and Aral seas started in the fi rst half of the 20th century (Bortnik & Chistyayeva 1990; Terziev et al. 1992). With the collapse of the Soviet Union, data on ice conditions for these seas became very scarce. Most published time series of ice cover parameters stop in the mid-1980s. For the past decade, data that reside in local archives are irregular, exist in heterogeneous forms (data from aerial surveys and fi eld research, satellite imag ery, etc.), are stored on different media, and are not available to the public. For the region of the northern Caspian Sea and lower Volga there are some recent initiatives to compile these data into a comprehensive atlas of ice features (Buharizin & Sharomov 2002) but this work is just in the beginning stage. For many years, global sea ice cover has been studied using satellite observations, especially from instruments operating in the microwave range, such as passive radiometers, SAR, radar altimeters, etc. (Allison et al. 2001). Numerous studies of ice cover variability have been conducted using passive microwave observations Ice cover variability in the Caspian and Aral seas from active and passive microwave satellite data