SPATIOTEMPORALCHARACTERISTICSOF EXTREMERAINFALL EVENTS OVER.TAVA ISLAND, INDONESIA

The patterns and trends of extreme daily rainfall within period o.f 1981 - 2010 have been analyzed for Java Island, Indonesia particularly East Java Province. A set of extreme indices recommended by WMO were calculated using high quality data fi-om 84 rain stations to express the frequency and intensity of those events. The spatial patterns was identified by mapping climatological mean of indices while temporal trends was assessed using the nonparametric Mann-Kendal test. The study found that the spatial pattern of extreme rainfall events over East Java Province is generally characterized by low frequency and intensity in the coastal area, and high frequency and intensity in the mountainous area: The dominant finding from trend assessment is not-significant trend. However, the consistently significant trend was observed in some districts. Rain stations in District of Ponorogo, Ngawi, Bojonegoro, Gresik and Sumenep showed significant negative trend for almost all indices whereas significant positive trend was found in District of Surabaya and Pasuruan. Key words: spatia-temporal characteristics, extreme rainfall events, Java Islan