Seasonal variation of the rainfall over Taiwan

Two different approaches [empirical orthogonal function (EOF) analysis and rainfall regime identification] were applied to analyse the seasonal variation in Taiwan rainfall using 15 coastal stations administrated by the Central Weather Bureau of Taiwan, during the period 1981-1997. The major findings are as follows: Using the EOF analysis, the major seasonal variations in Taiwan rainfall may be shown as a seasonal seesaw in rainfall between the southern and northern Taiwan modes following the alternation of the two East Asian monsoon components. The former mode is associated with the summer southwest monsoon, while the latter with the winter northeast monsoon. Four (spring, summer, summer-fall and fall-winter) rainfall regimes are identified by the second approach: the four regimes cover northwest, southwest, east, and northeast Taiwan, respectively. The southern Taiwan mode is primarily formed by the second rainfall regime, while the northern Taiwan mode by the fourth. The seasonal variation in Taiwan rainfall is formed by the transition of these four rainfall regimes; this is reflected by a counter-clockwise rotation in these rainfall regimes around the island. Copyright (C) 2000 Royal Meteorological Society.