Evolution of two oceanic extratropical cyclones as observed with the special sensor microwave/imager and the Geosat and ERS 1 altimeters

Abstract

The evolution of two marine cyclones across the North Atlantic and the North Pacific Oceans is followed with a combination of sequential passive and active microwave data. The special sensor microwave/imager (SSM/I) provides estimates of atmospheric parameters: integrated water vapor, precipitation, and ocean surface wind speed. The Geosat and ERS 1 altimeter data are used to derive sea state parameters along the satellite tracks: the significant wave height and the ocean surface wind speed. The SSM/I integrated water vapor gradients are used to locate and follow the evolution of the atmospheric fronts. In regions of precipitation, often located behind the atmospheric fronts, the SSM/I surface wind speed cannot be derived, while the Geosat and ERS 1 altimeter wind speed yields estimates of wind speed gradients across the fronts. It is shown that the combination of SSM/I and satellite altimeters permits additional observations of surface fronts with higher resolution both in space and time than those given in the National Meteorological Center analyses.