An analysis of the spatio-temporal variability of rainfall in the Philippines

Abstract

In response to the serious implications of changes in the local climate, this study describes the temporal and spatial patterns of rainfall variability for the Philippines. Precipitation and wet-day frequency are obtained from the 0.5-degree resolution gridded dataset of monthly surface climate of global land areas, excluding Antarctica, of the Climatic Research Unit (CRU) for the period of 1901-1990. Results indicate that high variability is located over areas during their respective rainy seasons. Among the three major islands, the rainfall in Luzon is more spatially variable during the wet and dry seasons. This may illustrate that the area is composed of different climate zones. Aside from standard deviation, a new indicator of variability based on the ratio of total rainfall to number of wet days is proposed in this study. It is found that the last decade is characterized by a high spatial variability, which lasted the entire rainy season. Information derived from this study may be used in effective land use planning and in updating the Coronas climatological atlas.