Diurnal variation of atmospheric water vapor based on GPS observations over Taiwan

Diurnal variations in the atmospheric vapor at Banchiao of Taiwan are studied by analyzing 30 min-averaged data in the summer of 1998. The surface meteorological measurements were mainly obtained from the Central Weather Bureau (CWB) of Taiwan. It is found that precipitable water (PW) is increased in the afternoon. The maximum of precipitable water appears at around 0900 LST. The diurnal range of precipitable water is larger on the days with than without rainfall events. Rainfall events often occur in the afternoon and early morning. We also examine the difference in the characteristics of the PW signatures with and without rainfall according to the occurrence of the times for the rainfall peak and the onset of rainfall.