ABSTRACTThis paper discusses a technique for mapping the area coverage of sea ice regardless of a cloud cover. Data from the AVHRR sensor of the NOAA-9 satellite were recorded on 22 May 1988. The study area is situated in the Arctic from Greenland to Norway including the islands of Svalbard. One of the thermal channels of the NOAA AVHRR sensor is used for the cloud inventory, but it is not suitable for separation of ice and open water due to similar brightness temperatures. The visible and near infrared channels of NOAA AVHRR are, on the other hand, suitable for ice and water separation. Problems arise when the ice margin disappears under a cloud cover. The visible and near infrared channels are highly correlated in the Arctic, mainly due to lack of vegetated surfaces. By extracting the small portion of uncorrelated features in these two channels, the extent of the ice cover is revealed even under the clouds. It is possible to estimate and map the extent of sea ice, cloud types and areas where ice and cloud overlap.