SoWMEX 2008(Southwest Monsoon Experiment 2008)主要的研究目的為:經由對南海地區西南氣流的熱動力特性的了解和加強台灣本島複雜地形降雨過程的認識，進而去改善定量降雨預報的準確度。 本篇使用SoWMEX 2008年NCAR(National Center of Atmosphreric Research) SPOL(10cm波長偏極化雷達)的雷達折射指數資料與台灣西南部氣象站的溫度、氣壓反演得到水氣壓(e)與相對溼度(RH)來討論6月14日(IOP 8)的水氣分布情形。 從高雄測站與繁華自動氣象觀測站所反演的相對濕度，與其實際觀測到的相對濕度的比較，可發現觀測與反演兩者有相當好的一致性，因此本研究進一步利用客觀分析方法將氣象站的氣壓與溫度場內插至網格點上與折射指數做反演，可得到水氣壓與相對濕度場的水平分布。本文探討水氣壓場、相對溼度場的變化情形，並討論其與回波場的關係。由於目前傳統濕度量測的缺乏，本研究藉由折射指數水氣場之反演，可增加水氣與降水系統交互作用之了解。 The major goal of SoWMEX/TiMREX is to provide the better data set to understand the kinematic and thermodynamic characteristics of the southwesterly flows during Asian summer monsoon. This unique data set is able to strengthen our basic understanding of physical processes leading to development of heavy orographic precipitation through intensive field observation campaign during the 2008 Mei-Yu season. This research used the refractivity data from NCAR SPOL (S-band polarimetric Doppler radar system) and the temperature/pressure data from the surface stations to retrieve water vapor pressure (e) and relative humidity (RH) and to illustrate the horizontal distribution of humidity. Results show there is a high agreement between retrieved and observed RH at KaoHsiung and FenHua stations. Based on this encouraging verification result, the temperature and pressure data from surface stations and the refractivity data from SPOL radar were interpolated onto the common Cartesian horizontal grids through objective analysis. The retrieved horizontal distributions of water vapor pressure and relative humidity during 00 LST to 12 LST on June 14 of 2008 were illustrated and compared with the reflectivity field. Because of the shortage of moisture data, this research provides the possibility of using radar refractivity to retrieve moisture field for future study of the interaction between moisture and precipitation.
