Model Vertical Profiles of Extreme Rainfall Rate, Liquid Water Content, and Drop-Size Distribution
Final technical rept. 1984-1985
AIR FORCE GEOPHYSICS LAB HANSCOM AFB MA
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This report provides a new model of hydrometeors and associated cloud-water content from the surface to 20 km. The model profiles at altitude were developed based on five surface rainfall rates 36, 84, 168, 432, and 1872 mmhr. The first three rates correspond to a frequency of occurrence of 0.5 percent, 0.1 percent, and 0.01 percent of the time during the worst month in the most severe area of the world for intense rainfall. The last two are the 42- and 1-min world record rainfalls. The surface rainfall rates were extrapolated aloft using results from previous studies. A large sample of drop-size distributions from intense rainfall collected during reconnaisance of Atlantic hurricanes tropical storms was analyzed. The data set was normalized and fit by a gamma distribution. This was used to specify the drop-size distributions and liquid water content for rainfall rates specifies at the surface and aloft. Concurrent cloud-water content was estimated. Results are presented at 2-km intervals.