本研究藉由觀測系統模擬實驗(OSSE)，在理想個案與完美模式的假設下，配合2020年臺美國際觀測實驗中之臺灣區域豪雨觀測與預報實驗計畫，評估地面掃描式儀器（包含S 與 Ka 波段雷達）所獲得之濕度場資訊，對於對流尺度天氣系統之影響。本研究將檢視同化雷達觀測(都卜勒風場與回波)之外，提供不同儀器之濕度場資訊時，其對於分析場與極短期預報0-6小時的改善能力。濕度場的資訊來源可分為: (1)NCAR雷達在Ｓ波段所提供之折射指數(Refractivity)， 其為近地表水氣資訊；(2)NCAR 雷達Ｓ與Ｋa 波段藉由回波能量衰減所獲得介於低層與中層之反演水氣資訊。透過理想個案之敏感度測試，亦能了解如何將都卜勒風場、回波與濕度場的高解析度資訊，作最有利的搭配，提供掃描策略設定之參考依據。 ;This project conducts the Observing System Simulation Experiment (OSSE) to evaluate the impact of assimilating humidity information. The observations are from ground-based scanning instruments which include NCAR S- and Ka- band radars. Based on assimilating Doppler wind and radar reflectivity, the study will examine the effect of providing humidity information from different radars, both in analysis and very short-term. The sources of the humidity information are from: (1) Refractive index (N) provided by the NCAR S-band radar. It is near-surface moisture information; (2) NCAR S-PolKa dual wavelengths radars are able to retrieve low- and mid-level moisture by the energy attenuation of reflectivity. Through the sensitivity tests of the idealized case study, it is expected to provide useful information and strategies for deploying different instruments for the international field experiment in 2020.
