The ISCCP_ICESNOW_NAT data set is a merged product containing separate snow and sea ice data sets. The values given are fractional coverage for 5-day intervals. The data are collected on a global equal-area grid with the cell area equivalent to 1 deg. latitude/longitude at the equator. The grid begins at the South Pole with the intersection of the Greenwich meridian (0 deg. longitude) and the ... South Pole as a cell corner. Ice/Snow Data Set contents include 5-day averages of snow and sea ice fractional coverage deduced from ship/shore station reports and satellite visible, infrared, and microwave imagery data.
The International Satellite Cloud Climatology Project (ISCCP) was established as the first project of the World Climate Research Program (WMO, 1984), to collect and analyze satellite radiance measurements to infer the global distribution of cloud radiative properties and their diurnal and seasonal variations. These data and analysis products will be used to improve the understanding and modelling of the effects of clouds on climate. The ISCCP version of the ice/snow data set includes only information concerning fractional coverage. The version actually used in the cloud analysis is changed in two ways: reductions to ice/snow presence and creation of "margin zones" in the data. The first of these is simply the process of converting the coded parameters in the original data set to code values that indicate only the presence or absence of sea ice and/or snow. The latter process fills in nearby grid cells in the data to indicate proximity to snow or sea ice covered locations. The second change is not included in the archived version of this data.