QuikSCAT's SeaWinds facilitates early identification of tropical depressions in 1999 hurricane season

Far from land and surface ship observations, most tropical depressions are identified by examining images from geostationary satellites for the presen ce of rotation of the convective cloud masses. During the 1999 hurricane se ason, surface wind vectors obtained by the SeaWinds scatterometer on the Qu ikSCAT satellite for the tropical Atlantic and Caribbean Sea were examined to test the hypothesis that developing tropical depressions (TDs) could be observed with this satellite sensor, before identification by the tradition al means. QuikSCAT was able to detect the presence of closed circulation in the surface winds before the systems were designated as depressions. The s atellite's unprecedented large swath width of 1800 km allows twice a day ob servation of most of the tropical oceans. SeaWinds data can, therefore, pro vide valuable guidance that are an important addition to the tools availabl e to the tropical cyclone forecasting community.