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    Please use this identifier to cite or link to this item: http://ir.lib.ncu.edu.tw/handle/987654321/71142


    Title: 利用觀測資料與多都卜勒風場反演系統做垂直速度上的驗證;Evaluation of vertical velocity retrieved by Wind Synthesis System Using Doppler Measurement
    Authors: 蘇俊瑋;Su,Chun-Wei
    Contributors: 大氣科學學系
    Keywords: 垂直速度;Verticlal velocity
    Date: 2016-07-21
    Issue Date: 2016-10-13 12:08:41 (UTC+8)
    Publisher: 國立中央大學
    Abstract: 垂直速度會影響對流系統的生成與消散,對於天氣系統也會有一定的影響,例如:垂直速度大的話,會有利於對流的發展;但由於觀測儀器主要為水平上的觀測,較無法直接得知垂直上的風場結構,因此垂直上的風場結構訊息對我們來講是很需要但卻很難得到的資訊。
    雷達觀測資料具有高時空解析度的特性,可以讓我們知道回波與徑向風,但從徑向風的觀測中我們只能得知風場是靠近雷達還是遠離雷達,而無法真正的知道三維的風場結構。
    為了從徑向風找回三維的風場結構Liou 和 Chang(2009)、Liou et al. (2012)、Liou et al.(2014)利用三維變分方法發展了多都卜勒風場反演系統( Wind Synthesis Using Doppler Measurement ,簡稱WISSDOM),它可以在複雜地形上做反演,也解決了傳統雷達所遇到的基線問題,同時也把渦度方程加入約束條件中,在近期的研究中WISSDOM對於天氣系統都能有好的反演結果,但在垂直速度反演部分還沒有真正的利用觀測資料來做驗證比較,無法去判斷反演出來的垂直速度的正確性。
    為了了解WISSDOM垂直速度所反演出來的好壞,吾人選了三個案例去做驗證,分別是2010年的凡那比颱風、銅鑼梅雨鋒面的觀測實驗、2013年的潭美颱風,前面兩個個案都有TEAM-R在做觀測且都有做垂直指向的掃描策略,因此可以利用垂直指向的觀測來做驗證,而在潭美颱風的個案中則是利用中壢特高頻雷達(VHF)去做驗證比較。
    根據WISSDOM反演出來的結果,在這三個個案中,垂直運動在一些區域內能反演出較好的結果,會有這樣的結果是由於觀測點上方的雷達覆蓋率與雷達本身對於整體的覆蓋率有關,當覆蓋率高時,就會有較好的反演結果,而且也發現終端落速對於垂直速度的反演也是有一定的影響力。
    ;The vertical velocity has strong correlation with deep convections in weather system , but due to limitation of observation , the three-dimensional vertical wind distribution is difficult to know. The radial wind observation from Doppler radar can provide three-dimensional wind information , but compare to horizontal wind , the direct vertical wind component is of minor percentage in the radar wind observation is rather rare.
    To retrieve the three-dimensional wind structure from Doppler wind observation , a Wind Synthesis Using Doppler Measurement (WISSDOM) based on variational method is developed by Liou and Chang(2009)、Liou et al. (2012)、Liou et al.(2014). WISSDOM performed reasonably well on recent application , however , the vertical velocity retrieval has never been verified by real observation accurately.
    In order to statistically understand the retrieval performance , three cases including typhoon Fanapi (2010)、Mei-yu front experiment in Tonluo observed by NCU X-band mobile radar (TEAM–R) and typhoon Trimi(2013) observed by VHF , are employed to perform the verifications on vertical velocity. The result show WISSDOM retrieval has good agreement with radar vertical pointing wind observation in this three cases. In addition , it is found the radar data coverage plays an important role on the accuracy of vertical wind retrieval and the terminal velocity is also sensitive .
    Appears in Collections:[大氣物理研究所 ] 博碩士論文

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