This is a raster product representing the fraction (in %) of each pixel covered with sea ice. The variable is extracted from the SSM/I images through the Comiso Bootstrap algorithm. This algorithm is more than 94 % accurate. The extraction is set up monthly by the Scottish Association for Marine Science. The product is a monthly average of all the information available from observations during the month. This number of observations is usually really close to 30. Indeed the SSM/I imaging of the Arctic is daily renewed, and SSM/I sensors can penetrate the clouds better than infrared sensors.