GPS determination on precipitable water vapor and analysis on its yearly variation

• Main Authors: Po-Long Chen, 陳博隆
• Other Authors: Chun-Sung Chen
• Format: Others
• Language: zh-TW
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/49640847129103028432

碩士 === 清雲科技大學 === 空間資訊與防災研究所 === 100 === In Taiwan, heavy rainfalls due to plum rain season or typhoons bring some serious natural disasters in recent years. Not only result casualties of human, but also affect significant loss of economy. Some continuous rainfall often happen to the countries of western pacific such as Taiwan, Japan and China during plum rain season on May or June every year. The rainfalls come from the troposphere of atmosphere is an unstable state and the role of an energy transfer on climate change. This study applied the observational data of the Central Weather Bureau in Taiwan and discussed the trend of the rainfall and the precipitable water vapor (PWV) of the atmosphere. Because the Global Positioning System (GPS) stations and the rainfall stations are not co-location, the 95 GPS tracking stations identify the shortest distance of 92 rainfall stations as to reduce the influence of the different environment. Moreover, the Bernese 5.0 software is used to calculate the zenithal wet delay (ZWD), and the experience formula is adopted to transfer the ZWD to PWV. In this study, we compared the PWV and rainfall data to show the trend and yearly variation during the period of 2006-2011, and reflected the variation of the ZWD. The results show that the PWV of annual variation is a consistent trend in different dis-tricts, because the water vapor in the atmosphere is a large scale phenomenon in Taiwan. There is an upward trend of the PVV data, and the annual increment is between 0.67 and 0.83 mm per year, which is inconsistent with the rainfall data. When the rainfall is higher, it usually has the airstream or typhoon events. According to the statistical analysis in this study, the changes of the rainfall are more relevant with the weather events in the past six years.