PRECIPITATION CHARACTERISTICS IN GREENLAND-ICELAND-NORWEGIAN SEAS DETERMINED BY USING SATELLITE MICROWAVE DATA

Precipitation characteristics and their connection with atmospheric co nditions are studied for the Greenland-Iceland-Norwegian (GIN) Seas du ring wintertime using satellite microwave (Special Sensor Microwave/Im ager) and SSM/T2 data. A snowfall algorithm using SSM/T2 data is prese nted, which makes it possible to estimate the total precipitation and the relative contribution of each precipitation component (rain or sno w) over open water. The monthly mean snowfall rate distribution compar es well with the snowfall frequency derived from shipboard present wea ther reports although no data are available for direct snowfall rate v alidation. The retrieved results show that more than half of the preci pitation falls as snow in the GIN Seas during winter and that the mont hly mean horizontal distributions of rain and snow have different patt erns. By examining the relationship between surface wind and precipita tion and conducting case studies, it is found that rainfall and snowfa ll are associated with different weather types: rainfall occurs mainly in low pressure systems, while snowfall is more likely associated wit h cold air outbreaks.