TREND OF DAILY RAINFALL AND TEMPERATURE IN PENINSULAR MALAYSIA BASED ON GRIDDED DATA SET

Abstract

A gridded data set with the size of 0.05 degree resolution (approximately 5.5km) which representing
ground observations of daily rainfall and temperature of Peninsular Malaysia has been created over 1975-2006.
The integration and processing of the variety of data sources and data assessment is also presented. The 32-year
period of the daily gridded rainfall and temperature data set were assessed to see how the daily mean rainfall and
temperature have changed over time and space. Northeast monsoon (NEM) contributes more rainfall over the
country compare to southwest monsoon (SWM). The rainfall trend during NEM is found significantly increased
at the 95% confidence level (7mm/season/year), meanwhile SWM rainfall does not pose any significant trends.
Both NEM and SWM temperature trends show significant increasing trends at 95% confidence level at
0.32oC/decade and 0.31oC/decade, respectively over the 32-year period. A drastic increased of mean temperature
(1.20oC) was found in Klang Valley over the 20-year period. The mean decadal temperature was found consistently
decrease as it approached the northern, east coast and southern part of the country.