WATER VAPOUR WEIGHTED MEAN TEMPERATURE MODEL FOR GPS-DERIVED INTEGRATED WATER VAPOUR IN PENINSULAR MALAYSIA

Abstract. This paper presents the development of T_M model by using the radiosonde stations from Peninsular Malaysia. Two types of T_M model were developed; site-specific and regional models. The result revealed that the estimation from site-specific model has small improvement compared to the regional model, indicating that the regional model is adequately to use in estimation of GPS-derived IWV over Peninsular Malaysia. Meanwhile, this study found that the diurnal cycle of T_S has influenced the T_M–T_S relationship. The separation between daytime and nighttime observation can improve the relationship of T_M–T_S. However, the impact of diurnal cycle to IWV estimation is less than 1 %. The T_M model from Global and Tropic also been evaluated. The Tropic T_M model is superior to be utilized as compared to the Global T_M model.