| 摘要: | 研究期間：10108~10207;It has long been widely accepted that the observed rain drop size distribution (DSD) can be satisfactorily modeled in terms of Gamma distribution. The relation between slope and shape parameters of the Gamma DSD can be empirically described by a polynomial of 2 degree, which is obtained by best fitting a second-order polynomial to the observed rain DSD data. In this project, an attempt is made to theoretically investigate the origin of the empirical relation and possible physical factors (such as vertical air velocity, change in drop size, atmospheric temperature, etc.) governing the property of the relation. This project is intended to be conducted in three years. In first year, the theoretical foundation of the empirical relation is investigated. Through this study, the limitation of the relation and the physical parameters affecting the variations of the relation can be realized. In second year, the Monte Carol Method will be developed and the relation will be theoretically simulated and studied. We hope that the physical factors that mainly control the relation can be clarified and the applications of the relation to precipitation estimate can also be investigated. In third year, by using the Chung-Li VHF wind profiler, between drop size distribution and the precipitation environment is investigated. We hope that through this investigation the influence of the physical factors associated with the precipitation environment, such as vertical air velocity, turbulence, air temperature, etc., on the change in the drop size distribution can be understood.It has long been widely accepted that the observed rain drop size distribution (DSD) can be satisfactorily modeled in terms of Gamma distribution. The relation between slope and shape parameters of the Gamma DSD can be empirically described by a polynomial of 2 degree, which is obtained by best fitting a second-order polynomial to the observed rain DSD data. In this project, an attempt is made to theoretically investigate the origin of the empirical relation and possible physical factors (such as vertical air velocity, change in drop size, atmospheric temperature, etc.) governing the property of the relation. This project is intended to be conducted in three years. In first year, the theoretical foundation of the empirical relation is investigated. Through this study, the limitation of the relation and the physical parameters affecting the variations of the relation can be realized. In second year, the Monte Carol Method will be developed and the relation will be theoretically simulated and studied. We hope that the physical factors that mainly control the relation can be clarified and the applications of the relation to precipitation estimate can also be investigated. In third year, by using the Chung-Li VHF wind profiler, between drop size distribution and the precipitation environment is investigated. We hope that through this investigation the influence of the physical factors associated with the precipitation environment, such as vertical air velocity, turbulence, air temperature, etc., on the change in the drop size distribution can be understood. |
