本計劃之目的在於探討如何由氣象衛星數據影像(日本GMS地球同步衛星 和美國NOAA衛星資料)來指定雲高,以做為其他分析或校驗之,如做為數值 預報模式校驗輸入,或雲導風校驗之用。 雲高參數在許多氣象應用上非常 重要,而在許多情況下與地區,雲高並無法順利獲得,如廣大海洋區域,因 此如何獲得雲高參數也一直是氣象遙測的研究子題之一, Fritz and Winston(1962) 而後又有數種利同衛星影像指定雲高的不同理論出現。但因各種雲高指定方法都 有其優劣與限制,也受限現有的氣象衛星頻道特性(如頻道權重函數)與數目,因 此至今尚無較完整作業化程序。本計劃的目地即在於針對台灣及其鄰近地區(東 亞地區)的雲系特性,嘗試開發出合適於台灣附近雲高指定方法。因此本計劃之 目的在於檢視(或校驗)現行於歐美各國衛星氣象中心所使用之諸雲高指定方法的 準確性,並嘗試修正或另行開發適用於指定台灣及其鄰近地區雲系之雲頂高度的 雲高指定方法。準確的雲高指定方法開發完成之後將有助於提昇雲導風(cloud motion winds)在對觀測資料缺乏地區(如廣大洋面地區)天氣預報的實用性; 在低緯傳統觀測資料嚴重缺乏地區之精確雲導風場可直接被同化進入颱風路 徑模式,預期將可顯著提昇模式的準確度。 在第一年的工作中,將分析比較各國衛星中心雲高指定方法,以了解各種 方法的優劣,在開發工作上,先以紅外線窗區頻道方法為主,由GMS影像資料 求取雲頂溫度,再與當地的氣溫垂直分佈比較,以求得雲高(Fritz and Winston, 1962)。另外,本研究也將以NOAA二氧化碳頻道資料初步測試二氧化碳吸收法 雲高指定法的可行性,並為做和GMS雲高精度的比對。 The goal of this study is to investigate the problems regarding the estimation of cloud height using meteorological satellite imagery for the other weather analysis and applications, such as verification of numerical weather model input or cloud motion wind input. Cloud height parameter is very important in many meteorological applications. Unfortunately, cloud height can't be observed or measured in many area or situations. For example, over ocean area. Therefore, how to develop a practical method to derive cloud height using remotely sensed data has been an important study topic. Fritz and Winston (1962) proposed a infrared window channel method was one important base of cloud height estimations because its simple and practical algorithm. After that, several main cloud height estimations were developed. So far, there not is one integrated cloud height estimation is proper for most cloud system because theory or data limitation. Since there not is one operational cloud height estimation method existed. The aim of this study try to investigate or verify the various cloud height estimations used in other operational unit, especially in USA and Europe countries, and try to develop a cloud height estimation method for Taiwan and East Asia area. If the goal was reached, the applications will be great. For example, to verify the CWB NWP model, and to improve the accuracy of cloud motion wind which will improve the typhoon path prediction accuracy. In the first year work, this study will focus in the analysis and comparing of other operational units other countries to pick up the good algorithms and methods. Meanwhile, this study will focus in the developing and improving of infrared channel method. Besides, this study will do primary test of CO2 absorption method using NOAA data to investigate its practicality, and to compare the accuracy of cloud height derived using GMS data. 研究領域:8808 ~ 8912