Abstract

An algorithm converting satellite-measured microwave radiances to rainfall rates was used to analyze the rainfall patterns of western North Pacific tropical cyclones (typhoons) mainly of the 1987 season. Having realized that these rainfall rates were reasonable and compared favorably with those existing in the tropical cyclone climatology, they were correlated to the 24-h Dvorak intensifies of typhoons in search of diagnostic insights and prognostic aids.

Special Sensor Microwave/Imager rainfall rates from 27 map times of 12 typhoons were computed. Mean rainfall rates were computed for various rectangular areas within a typhoon. Those storms filled the mean areal rainfall-rate distributions along an x axis that showed several maxima. Rain volume rates within boxes of various sizes centered an the storms correlated differently with the future 24-h pressures. Correlation between these two parameters was −0.68 for a 444-km box, −0.38 for a 666-km box, and 0.10 for a 888-km box. Results further showed that a northwestward-moving storm was likely to deepen, if lighter (≤3 mm h−1) rainfall rates dominated a 222-km box.

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