First ISCCP Regional Experiment (FIRE) Atlantic Stratocumulus Transition Experiment (ASTEX) ERS-1 Wind Scatterometer Data

The First ISCCP Regional Experiments have been designed to improve data products and cloud/radiation parameterizations used in general circulation models (GCMs). Specifically, the goals of FIRE are (1) to improve the basic understanding of the interaction of physical processes in determining life cycles of cirrus and marine stratocumulus systems and the radiative properties of these clouds during their life cycles and (2) to investigate the interrelationships between the ISCCP data, GCM parameterizations, and higher space and time resolution cloud data. To-date, four intensive field-observation periods were planned and executed: a cirrus IFO (October 13 - November 2, 1986); a marine stratocumulus IFO off the southwestern coast of California (June 29 - July 20, 1987); a second cirrus IFO in southeastern Kansas (November 13 - December 7, 1991); and a second marine stratocumulus IFO in the eastern North Atlantic Ocean (June 1 - June 28, 1992). Each mission combined coordinated satellite, airborne, and surface observations with modeling studies to investigate the cloud properties and physical processes of the cloud systems.The wind scatterometer aboard ERS-1 scans a 300km wide zone, situated 300km right of the satellite track. Orbital data are given for each orbit (number 1 to 501), starting from the orbit node (10:30 solar time for the descending orbit at the equator). The complete cycle duration is 35 days. Data from the ASTEX domain have been extracted for June, 1992 from the fast delivery product tapes provided by ESA. The raw data have been processed by ESA, using an algorithm (CMOD2) which has has revealed to fail in a number of cases. Itresults in particular in erroneous wind direction (180deg ambiguit\ y). These data thus cannot be used without a careful examination of their coherence.