Features of the Intrinsic L-Band Radiation of the Gulf of Ob during the Freeze-Up Period

This article analyzes seasonal and interannual dependences of brightness temperature in different zones of the Gulf of Ob according to data from the MIRAS radiometer (SMOS satellite). It is shown that, while the brightness temperature dynamics of the freshwater zone of the Gulf of Ob (the estuary and the central zone) is similar to that of freshwater lakes, this dynamics in the seawater zone is different. The authors explain this difference by an increase in water salinity and, consequently, an increase in radiation absorption in the lower ice layer, which is in contact with the water surface. The regularities of seasonal variations of brightness temperature in different zones of the Gulf of Ob and related ice-cover phases can be used to assess salinity and water mixing in large estuaries of the Arctic in winter based on satellite microwave radiometry.