ИСТИНА

Open water season (OWS) changes in the Kara Sea coastal zone near Marresalya are analyzed using satellite-derived sea ice concentration data. In addition to state of the art 15% threshold method, original data-based rolling window approach was implemented to define the open water season characteristics (start/end dates, duration). To validate the results sea cover observations on Marresalya station, sea ice charts and Terra/MODIS images were used. Linear trend coefficients and RMSE (comparing with sea ice cover observations) were used as the main quality metrics.Near Marresalya the open water season duration increased significantly (α-level < 0.05) in recent decades (1979-2015) with the mean rates of 7-9 days/decade. The OWS start dates shifted to earlier dates with the mean rates about 4-6 days/decade while the end dates significantly shifted to later period with mean rates of 3 days/decade. Obtained OWS characteristics for nearshore satellite data pixels correspond to observations and sea ice charts archives. It is shown, that satellite-derived sea ice concentration data could be successfully used for the coastal zone cases.