台灣地區近年來飽受颱風豪雨肆虐，中央大學大氣科學系雷達氣象實驗室，為提升雷達降水估計及預報能力，已於2004年11月底成功將都卜勒雷達完成偏極化功能升級。此種偏極化功能除了可以在三維空間中，測量水滴大小、扁平度、粒子個數分佈等雨滴譜儀參數外，並且提供不受地形影響之電磁波相位資料。偏極化雷達的降雨即時觀測配合雨滴譜儀網，將成為精密校正台灣北部雷達站/雨量計網降水估計最重要並無可取代的工具。本團隊在2005年的計畫中積極進行偏極化雷達觀測，並從所得到的參數發展反演雨滴譜及降雨率的方法，從2005年的計畫結果看來C–波段雙偏極化雷達對定量降雨估計為豪大雨的結果相當良好。因此此雷達對防災的定量降雨應該是足夠的。2006年本委辦計畫之目的：提供中央大學偏極化都卜勒雷達資料，配合北部雷達站網、雨量計網、雨滴譜儀網，研發產生最佳降水估計流程、發展自動化數值程式及即時降雨率分布產品，以計畫主持人在國科會自然處計畫發展出來之偏極化雷達參數降水估計應用方法，以及在永續氣象防災雷達降水計畫發展之雨滴譜儀導出之雷達降水公式統計及雨量站網進行驗證，維護中央大學偏極化/都卜勒氣象雷達；在台灣北部進行即時雙偏極化雷達觀測，並且和雨滴譜儀相互配合，以提升水文降水資料之品質。 Taiwan area has been suffered from the Typhoon, heavy rain, and thunderstorm in this years. However, because of the different rain drop distribution characteristics of each rainfall event, the variation of the relations between radar reflectivity and the rainfall rate estimation (Z-R relation) is quite large. So the single formula for the Z-R relation often underestimates the rainfall during heavy rain. The complex terrain also cause ground clutter and the blocking of radar beam energy, these factors also induce rainfall estimate errors. In order to promote the ability of rainfall estimation by radar, the radar meteorology laboratory in National Central University had upgraded the NCU Doppler radar to Doppler/dual polarimetric radar successfully on November 2004. During 2005 project, the polarimeric data sets in many heavy rain cases were collected, the results proved that the polarimetric variables can provide drop size distribution, drop oblateness, and hydrometer types in a precipitation system. The most important result is the rainfall average estimate is much more accurate than the Doppler radar. The real time drop size distribution from distrometer can be used to calibrate the new polarimetric radar. In 2006, this project will provide the polarimetric radar rain map , develop the automatic rainfall rate estimation procedure and maintain the NCU polarimetric radar. 研究期間：9504 ~ 9512
