不同季節以及不同降雨型態的雨滴粒徑分佈(DSDs)特性以及降雨的垂直結構，不僅 關係著降雨的微物理性質，也影響雷達定量降雨估計的正確性，本計畫將利用台灣全島過去多年地面雨量站網、雨滴譜監測網以及全島雷達網的長期間觀測所得之巨量資料，進行不同區域、不同季節的雨滴粒徑與 雷達回波垂直結構的統計分析，以了解降雨之微物理性質，利用降雨強度以及雷達 回波垂直結構可以將降雨區分為對流性、層狀性，以及淺對流等三種型態，並將比 較不同地面雨滴譜儀(如2DVD、Parsivel、JWD等)雨滴粒徑統計特性之差異，結合雨滴粒徑與雷達回波可以建構不同季節與不同降雨型態的雷達回波定量降水估計公 式，進一步則將利用雙偏極化雷達參數所建立之降雨估計關係式來進行比對與驗證 。同時結合地面、探空、氣象衛星與氣象雷達特別是雙偏極化雷達之觀測探討比較不同區域、不同季節與不同降水系統所伴隨之動力與降雨雲微物理過程之特性差異。本研究第一期已完成台灣北部過去十年之雨滴譜儀資料收集分析統計，特別是JWD撞擊是雨滴譜儀資料之收集與格式整理以及資料品質檢定與雨量觀測資料比對，建立雨滴譜儀資料庫，分析比對撞擊式雨滴譜儀與垂直回波的關係，並已在ＪＧＲ、JMSJ以及Scientific Reports等期刊上發表多篇論文。本計劃將以此資料庫為基礎，建立不同區域、不同季節與不同降水系統的降雨公式與反演的偏極化雷達參數，提升定量降水估計與預報的能力。由北台灣雨滴粒徑與降水物理特徵，進而擴展分析氣象局全台灣Parsivel雨滴譜儀站網的資料，了解不同區域的雨滴粒徑與降水特徵，並和都普勒與雙偏極化雷達觀測做結合，建構更準確的雷達降雨估計技術。 降水對土壤的侵蝕作用不但關係著農業、水資源與土地利用之規量，而且也影響坡地災害的預警與防治，本計畫將結合地面雨滴譜儀觀測、地面雨量站、雷達估計降水強度分布，以及雙偏極化雷達之三維雨滴粒徑反演資料，進行不同型態降水對坡地土壤侵蝕作用與水文防災評估應用之研究。 ;The statistical characteristics of raindrop size distributions (DSDs) and vertical structures of rainfall during the past ten years in Northern area of Taiwan are studied using measurements from a ground-based disdrometer network and radar network in the northern part ofTaiwan. Based on rainfall intensity and vertical structure of radar reflectivity the observed rainfall will be classified into convective, stratiform and shallow precipitation types. The statistical characteristics of DSDs based on different ground-based disdrometers will be intercompared and analyzed. Based on the statistics of DSDs and radar reflectivity, the Z-R relationship will be constructed with respective to different season and different precipitation type. Finally rainfall estimation relationships using polarimetric radar measurementswill be derived compared and discussed. An optimum radar QPE technique could be constructed in Taiwan. In the first year of this project, the DSD data base was constructed, especially for the format and quality control on JWD disdrometer data. Moreover, there were two papers have been published in JGR. In the future works, by using these data base and retrieved dual polarization radar parameters, the optimal QPE technique could be improved with several formulas. According to the previous experience on the characteristics of DSD and precipitation, the Parsivel, doppler and duel-polarization radar data from CWB network around Taiwan in different regions could be analyzed, in order to realize precipitating cloud microphysics process and quantitative precipitation estimation.. The kinetic energy with which raindrops impact the soil surface is one of the key factors that responsible for the soil erosion. The rainfall intensity and kinetic energy relations obtained from the RSD play a key role in the rainfall-induced soil erosion. Estimating kinetic energy from rainfall intensity records by using empirical kinetic energy-rainfall intensity (KE-I) relationships is the most widely used method.In this study rainfall erosivity by using RSD information will be conducted and KE-I relations for different precipitations types over Taiwan will be studied too.
