Simulation of rain events from rain‐gauge measurements

Abstract

AbstractPoint rainfall as measured by a rain‐gauge is examined in terms of a space and time dependent rain event. The rain event is determined such that the total number of rain events in any one year account for at least 80 per cent of the annual area rainfall. The remaining fraction of annual rainfall is considered to be rainfall due to isolated unorganized rain systems. A 1‐year record from 19 digital rain‐gauge recorders over a 600 km2 area in the vicinity of the Kennedy Space Flight Center is used. Each tipping bucket rain‐gauge has a resolution of 1 minute 0.25 mm.Rain rates, duration, areas and frequency of occurrence are presented for nearly 200 rain events identified in a single year. Strong seasonal signals are seen particularly in extreme rain events, which produce more than 90 mm of rain per event, account for 60 per cent of the total network rainfall but occur less than 22 per cent of the time. A simulation of the detection of the extreme rainfall events by a remote sensing system such as TRMM suggests that the satellite will see only 10 per cent of the rainfall due to extreme rain events. The results illustrate the difficulties of sampling convective rainfall, especially over a continental tropical area such as Florida, by an orbiting platform.