Abstract
The mechanism of heavy rainfall in the Philippines was analyzed, taking an extraordinarily heavy rainfall of July 1972 which, for example, brought the record monthly precipitation to 4774.5mm at Baguio.
There seems to be two cases of heavy rainfall which correspond to two sets of atmospheric conditions. One is when a typhoon passes over or near the islands, and a heavy rain occurs, lasting for two to three days. The other is when a typhoon (or typhoons) comes to a halt near the islands and a monsoon current flows in from the South China Sea. In this case heavy rainfall continues for a prolonged period.
Thunderstorms are another important type of heavy rainfall for the region. The mean life time of this is shorter than 45 minutes.
In the same season, Japan also has heavy rainfalls caused by the combined effects of typhoons and Baiu-fronts. There is a close connection between the heavy rainfalls of these two regions.
