Low frequency and quasi-biennial oscillations in the Malaysian precipitation anomaly

The spatial and temporal variability of the precipitation anomaly in Malays ia in the quasi-biennial (1.5-2.5 years) and the low-frequency (3-7 years) bands were investigated. The oscillations in both bands contributed a signi ficant proportion of the variance in the precipitation anomaly. The most do minant modes for both bands had large impacts on the stations in Sabah, Sar awak and on the east coast of the Malaysian peninsula. These dominant modes had a similar manifestation, i.e. the stations experienced enhanced rainfa ll during periods of large negative anomaly of sea surface temperature (SST ) in the central-eastern Pacific Ocean and suppressed rainfall during perio ds of large positive SST anomaly. Hence, these areas may face severe drough t during an El Nino event and flood during La Nina. Both bands appeared to have large-scale coherence with SST, sea level pressure and zonal wind over the tropical Pacific and Indian Oceans and South China Sea. However, the t wo signals differed with respect to timing and propagation. Copyright (C) 2 001 Royal Meteorological Society.