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    Please use this identifier to cite or link to this item: http://ir.lib.ncu.edu.tw/handle/987654321/5022


    Title: 台灣土地利用型態對MM5模擬局部環流之影響
    Authors: 曹嘉宏;Jia-Hong Cao
    Contributors: 大氣物理研究所
    Keywords: 土地利用;MM5;land-use;MM5
    Date: 2007-07-05
    Issue Date: 2009-09-22 09:43:14 (UTC+8)
    Publisher: 國立中央大學圖書館
    Abstract: 地表過程不僅牽涉地氣間的交互作用,以影響天氣與區域氣候的特性,在模式中地表過程要能正確的發生作用,正確的土地利用型態分布與良好的參數化是決定性的因子。台灣經濟起飛,都市高度發展以後地貌已經有許多的改變,目前MM5所使用的美國地質調查局(USGS)所提供的土地利用型態資料,因為使用太過老舊的台灣土地分類資料,已經無法反映台灣真實的土地利用情形。因此,台灣中鼎公司(CTCI)利用內政部空照圖,將其數位化成台灣及鄰近地區的高解析度土地利用資料。CTCI與USGS兩種土地利用資料差異最大的地方為都市地區的大小與分布差異,水旱田的比例以及山區混合林的分布範圍。不同的土地利用資料所相對應的土壤參數如反照率、粗糙長度、土壤濕度等皆不相同,這些參數是模式在計算地表能量交換與地表特性時的重要依據,故本研究比較兩種不同的土地利用資料對於MM5模式的影響,討論改變土地利用資料之後,模擬台灣局部環流的差異。 變更土地利用資料之後,土壤濕度有很大的差異,尤其在較大的都會區如台北、台中,旱作物分布的地區,這些差異使可感熱通量與潛熱通量的比例有很大的不同。因CTCI中都市區域分佈明顯比USGS廣,且旱作物的區域也較多,乾燥的地表狀況造成在這些地區的溫度以CTCI為土地利用的模擬結果略比USGS的結果高溫,海風環流隨之發展得更快速,風速也較強。模擬與測站溫度比對上,以CTCI與USGS為土地利用分布的模擬結果皆有高估的情況,在相關係數方面兩者皆達0.9,但以RMAE(root mean squared error)來看,除了高雄站以外,其餘的地區都是USGS的模擬結果與測站觀測值之間的差異較小。 土地利用參數設定的敏感度測試,結果顯示土壤濕度的增加可以改善地表溫度高估的模擬誤差,但土壤濕度並非是全台灣統一增加,而是需要對於各個土地利用型態分別處理。在粗糙度的部分,增加都市與混合林這兩種類型的粗糙度,例如將都市的粗糙長度由50cm改成150cm,森林的部分改成100cm,在風速上有較好的模擬結果。 In order to well predict atmospheric conditions in Taiwan Island, the land surface processes must be accurately described through including the detailed land use data and the reasonable surface parameters. In the past few decades, the land use in Taiwan has changed quite large, especially in an urban environment area. The U.S. Geological Survey (USGS) 25- category land use data used nowadays in the Fifth-generation Mesoscale Model (MM5) is out of date in Taiwan. The China Technical Consultants Inc. (CTCI) land use data was digitized with the aerial photograph from Ministry of the Interior (MOI). The apparent difference between CTCI and USGS land use data is the range and location of urban area, cropland and forest. Soil parameters are different in each type of land use, such as albedo, roughness length and soil moisture. These parameters are close related to the land surface processes in model. This paper presents the impact of different land use data on MM5 model simulates, especially the development of local circulation in Taiwan. Soil moisture was apparently different between two land use data, especially in urban area and dryland cropland. Different soil moisture would change the heat flux condition and result in changes temperature patterns. The model output with CTCI land use data has higher temperature than the output with USGS data. Correlation between station observation and model output with each land use data are more than 0.9, but root mean squared error show that the bias between station observation and the model output with USGS is less than CTCI. The sensitivity test for land use parameters shows that increasing soil moisture and roughness length can reduce the bias of temperature and wind speed respectively.
    Appears in Collections:[大氣物理研究所 ] 博碩士論文

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