| Summary: | 碩士 === 健行科技大學 === 空間資訊與防災研究所 === 101 === The applications of Global Positioning System （GPS）are not only existed in the engineering field, but also extended to the scientific field of meteorology. Through the analysis of zenithal wet delay from GPS observation, it could be further applied to estimate the vertical total perceptible water vapor（PWV）in the atmosphere. This technique has been implemented worldwide by the meteorological societies for more efficiency in weather forecast.
In this study, tropospheric water vapor derived by GPS data and rainfall recorded at the precipitation stations, both collected for the period of 2006-2012, are compared for further discussion. The trends of PWV and rainfall around Taiwan are analyzed, and the relationship between PWV and station elevation are also established. Moreover, the harmonic analysis is adopted to realize the trends of rainfall and tend to further explore the change of PWV in the atmosphere associated with the occurrence of heavy rainfall.
The results show that the higher elevation of GPS station, the lower estimate of PWV, along with the function of the elevation increasing every 100 m, the water vapor falling 1.1 mm to 1.8 mm. The trends during the period of 2006-2012 can be found in Taiwan that the precipitation is increased linearly, but the recorded rainfall is decreased. This phenomenon indicates that more water vapor is needed to arouse rains; and it somehow reflects the fact that the drought might be more evident in the Taiwan area.
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