臺灣地區雨滴譜分布特性與降雨動能之研究

臺灣目前所使用之單位降雨動能公式為Wischmeier and Smith (1958)以Laws and Parsons (1943)於美國華盛頓利用麵粉糰粒法量測100顆自然降雨之雨滴粒徑為基礎，以外插法求得其關係式，故此單位降雨動能公式係以美國地區為基礎而建立，倘若繼續沿用美國地區的單位降雨動能公式會因地區降雨特性及雨滴量測方法不同，可能會使得數據容易發生高估或低估之情形。本研究欲使用雷射雨滴譜儀量測臺灣北、中、南、東部地區之雨滴譜資料(雨滴終端速度及粒徑)，分析不同地區之降雨特性，並建立適用於臺灣地區之單位降雨動能公式。本研究於臺灣北部-華梵大學、中部-凍頂工作站、南部-屏東科技大學及東部-斑鳩分場分別架設雷射雨滴譜儀，利用儀器量測每五分鐘之雨滴譜資料。分析結果顯示，凍頂工作站與屏東科技大學所量測的雨滴終端速度及粒徑皆大於斑鳩分場與華梵大學。華梵大學、凍頂工作站、屏東科技大學及斑鳩分場之降雨強度與降雨動能關係式分別為E=0.1689(I)-0.0906，R2=0.89、E=0.3142(I)-0.2244，R2=0.95、E=0.1821(I)-0.0591，R2=0.91及E=0.1656(I)-0.0585，R2=0.92，且於相同降雨強度下，降雨動能由大至小依序為凍頂工作站、屏東科技大學、華梵大學、斑鳩分場。截至2019年12月為止，華梵大學、凍頂工作站、屏東科技大學及斑鳩分場之有效降雨事件分別為79場、130場、114場及13場，並建立適用於各地區之單位降雨動能公式，分別為e=0.047+0.0666 log(I)，R2=0.41、e=0.099+0.1052 log(I)，R2=0.46、e=0.089+0.0620 log(I)，R2=0.40及e=0.073+0.0583 log(I)，R2=0.48，於相同降雨強度下，單位降雨動能由大至小依序為凍頂工作站、屏東科技大學、斑鳩分場、華梵大學。

關鍵字

雷射雨滴譜儀；雨滴譜資料；降雨強度；降雨動能

並列摘要

The formula of unit rainfall kinetic energy used in Taiwan is based on the relationship established by Wischmeier and Smith (1958), which is based on the particle size of 100 natural raindrops measured by Laws and Parsons (1943) in Washington, DC, using the flour method. In the study, the raindrop size distribution (raindrops velocity and diameter of raindrops) were measured at Huafan University, Dong Ding Workstation, Pingtung University of Science and Technology and Banjiu Branch with laser raindrop spectrometer, analyze the rainfall characteristics of different regions, and establish formula of rainfall kinetic energy for Taiwan. The results showed that the raindrops velocity and diameter of raindrops measured by Dong Ding Workstation and Pingtung University of Science and Technology are faster and larger than Huafan University and Banjiu Branch. The relationship between rainfall intensity(I) and rainfall kinetic energy (E) is analyzed and discussion on different rainfall kinetic energy formula.The regression equations of E and I are E = 0.1689(I) - 0.0906 (R2 = 0.89), E = 0.3142(I) - 0.2244 (R2 = 0.95), E = 0.1821(I) - 0.0591 (R2 = 0.91) and E = 0.1656(I) - 0.0585 (R2 = 0.92), respectively.In the same rainfall intensity, the rainfall kinetic energy is decreased in the order of Dong Ding Workstation, Pingtung University of Science and Technology, Huafan University and Banjiu Branch. As of December 2019, the effective rainfall events of Huafan University, Dong Ding Workstation, Pingtung University of Science and Technology and Banjiu Branch were 79, 130, 114 and 13, the regression equations of rainfall intensity (I) and unit rainfall kinetic energy (e) are respectively e=0.047+0.0666 log(I) (R2 = 0.41), e=0.099+0.1052 log(I) (R2 = 0.46), e=0.089+0.0620 log(I) (R2 = 0.40) and e=0.073+0.0583 log(I) (R2 = 0.48). In the same rainfall intensity, the unit rainfall kinetic energy is decreased in the order of Dong Ding Workstation, Pingtung University of Science and Technology, Huafan University and Banjiu Branch.