| 摘要: | 為了解劇烈降水系統的三維動力及雲物理場的特性，偏極化雷達扮演著重要的角色，其徑向風場(radial velocity)、差異反射率(differential reflectivity, ZDR)、差異相位差(differential phase shift, PHIDP)、比差異相位差(specific differential phase shift, KDP)及相關係數(correlation coefficient, RHV) 觀測變數，利用三維變分法及模糊邏輯法，可得到三維動力及雲物理場的分佈，而其中的雨滴粒徑分佈(Raindrop size distribution, RSD)，也可以透過偏極化雷達參數反演而得，整合上述資料後，可分析降水系統初生期、發展期及消散期的結構特性。輔以高解析度對流尺度數值模擬，其有完整雲物理過程的模擬，計畫第一、二期所發展的偏極化雷達變數運算子(forward operator)，搭配區域數值預報模式(WRF)，挑選SoWMEX/TiMREX實驗期間劇烈降水個案，針對其：空間解析度、雲物理參數化法、地表參數化法及輻射參數化法等，已進行敏感度測試。結果顯示其可幫助了解劇烈天氣系統的降水過程，結果顯示數值模式與觀測分析有相當大的差異。本計劃預計進一步分析上述模擬結果，並規劃另行分析該降雨事件與地形交互作用的影響，包含：三維動力場、雲微物理場及雨滴粒徑分佈，以了解劇烈天氣系統的降水過程。 第一年：預計延續分析SoWMEX/TiMREX實驗期間的劇烈降水個案，比較數值模式模擬結果，與雙偏極化雷達反演、地面雨滴譜儀網觀測。建立分析工具，訓練專任、兼任研究助理熟悉地面雨滴譜儀網觀測資料。預計整合地面雨滴譜儀網觀測資料，與雙偏極化雷達觀測資料，解析中尺度降水系統的降水過程。 第二年 ：逐步整合台灣雨滴譜儀觀測儀器，包含ＰＡＲＳＩＶＥＬ、ＪＷＤ和2ＤＶＤ，根據NCAR S-PolKa的位置，在距離S-PolKa約30~50km的距離，建立高空間( 5 km，將數個雨滴譜儀以二維陣列的方式佈建，預計每維度至少３部雨滴譜儀)、時間(1 min)解析度的雨滴譜儀觀測網，並搭配台灣降水雷達網，進行預實驗。目的在確認儀器配置的合理性，並初步收集高空間、時間解析度的雨滴譜資料，初步建立台灣降水雲物理過程概念模式。 第三年 ：搭配NCAR S-PolKa， ;The dual-polarization radar plays an important role in understanding the characteristics of the kinematic and microphysical fields of the severe precipitation systems. The spatiotemporal distributions of the kinematic and microphysical fields can be derived from the dual-polarization measurements of: radial velocity, differential reflectivity (ZDR), differential phase shift (PHIDP), specific differential phase shift (KDP) and correlation coefficient (RHV) via the variational-based multiple-Doppler radar synthesis method and fuzzy logic method. Moreover, the drop size distribution (DSD) of rain can also be retrieved from dual-polarization radar as well. Therefore, the evolutions and the structural characteristics of initiating, developing and dissipating stage of the precipitation systems can be investigated. In the previous two projects, the numerical simulation (WRF, NCAR) with sophisticated microphysical parameterization scheme and the dual-polarization moment forward operators were applied to the heavy precipitation event during SpWMEX/TiMREX. The results have shown some similarity compared to radar observations, but with some major discrepancy in DSD. The sensitivity test of various configures including spatial resolution, microphysical schemes, land surface scheme and radiation schemes will be further investigated and validated against the kinematic and microphysical retrieval from radar observations in the following project. In this three project, First year, continuing the study of the heavy precipitation event from SoWMEX/TiMREX. The detailed comparison between WRF simulation and S-POL observations will be continued. Moreover, the DSD observation from disdrometer network will be further investigated as well. The integrated examination from NWP simulation and various observations will be carried out. The analysis tools and concept model will be developed in this year. Second year, design and deploy the PARSIVEL disdrometer for TAHOPE. The high density disdrometer network with high spatial (two dimensions array network with at least three disdrometer in x and y axis with range resolution of 5 km) and temporal (1 min) resolution. The location of the disdrometer network should be coordinated with NCAR S-PolKa. The purpose is to examine the practicability of the deployment and collect the high spatiotemporal DSD data. Develop the preliminary concept model the precipitation process. Third year, participate TAHOPE and further utilize S-PolKa measurements from both S-band and Ka-band frequency. Further analyzing the evolution of the precipitation systems including the DSD, microphysical and kinematics fields. Verify and revise the concept model the precipitation process. |
