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    Please use this identifier to cite or link to this item: http://ir.lib.ncu.edu.tw/handle/987654321/5004


    Title: 地表特性對台灣及鄰近地區氣候影響之模擬研究
    Authors: 宋馥淇;Fu-Chi Sung
    Contributors: 大氣物理研究所
    Keywords: 地表模式;地表特性;土壤溫度;land surface model;surface characteristic;soil temperature
    Date: 2006-07-04
    Issue Date: 2009-09-22 09:42:52 (UTC+8)
    Publisher: 國立中央大學圖書館
    Abstract: 正確的使用地表參數資料與地表模式,可以明顯改善氣候模式的模擬結果,但台灣地區有關地表特性的觀測資料非常缺乏,幾乎沒有適合的土壤與地表資料可供使用。因此本研究首先利用off-line NOAH LSM(以下簡稱off-line)模擬台灣地區的地表及土壤資料,並將此土壤資料使用在MM5模式的下邊界及土壤層中。藉由MM5模擬台灣及鄰近地區在2001年5月到8月的氣候狀況,對照實際觀測資料,來了解使用這些土壤資料對台灣及鄰近地區的氣候所產生的影響。另外,本研究以是否使用off-line土壤資料與資料同化的差異,做四組實驗組模擬,並在使用off-line土壤資料的組別中,在沿海測站附近採用較低的土壤溫度初始值。藉由比較各實驗組之模擬結果,探討氣象場與土壤之間的交互作用。 off-line NOAH LSM可以正確地模擬出台灣地區土壤溫度年週期變化,但溫度值普遍偏低,且土壤呈現長期偏濕的狀態。造成模擬差異產生的原因,可能與NOAH LSM的發展主要是以美國大平原區進行的地表觀測實驗為基礎有關。大平原區主要的植被為無樹草原,氣候較為乾燥且乾溼季明顯,與台灣的季風氣候有很大不同。另外,LSM亦需要正確的台灣地區植被與地表等觀測資料,但這些資料在台灣地區極為有限,這對模式的驗證與修正有一定的困難度存在。 模式對台灣鄰近地區氣候的模擬結果顯示,最大的溫度場差異發生在30∘N到黃海與熱帶地區的海面上,前者可能與積雲參數化方法的使用有關,而熱帶地區則有過多的水氣吸收大量的外溢長波輻射,使得模式在黃海有較低溫而在熱帶海面上有較高溫的偏差。而模式對台灣地區模擬的溫度值普遍偏低,可能與模式中的土壤層溫度較低且土壤濕度較高有關。而對於颱風、鋒面過境等天氣事件,模式模擬對於其強度模擬仍需加強。 由於土壤層與地表、大氣的交互作用,較低的土壤溫度初始值使得地表溫度與2公尺溫度較低。在台灣地區,使用off-line土壤資料的各實驗組在各土壤層有負的溫度偏差,因為土壤熱量向下傳遞的時間延遲(100公分深的土壤約有1個月的延遲),溫度值由低溫回復的時間出現差異。在台灣上空較為低溫的空氣,經由模式的調整與風場傳遞,使得溫度場在兩組使用不同土壤資料的模擬結果比較中,於中國大陸出現東北-西南波形的差異分布。 It is helpful to improve long-term climate simulation more reality by using land-surface parameterization. The land-surface observations are very short of in Taiwan, and it almost has no applicable data for simulation using. In this study, we utilize off-line NOAH LSM to simulate land surface and soil data of Taiwan, then put in MM5 with low boundary condition to simulate climate from May to Aug in 2001. Compare the simulation result with ECMWF reanalysis data to find the impact of using these soil data. There are four experiments with different soil data, data assimilation, and initiation soil temperature, to study the interaction between atmosphere and soil. The off-line NOAH LSM could simulate correct soil temperature annual change, but the temperature values are in general lower than the observations. The soil moisture might be too wet for a long term. Owing to the climate difference between Great Plain and Taiwan, the simulation of off-line NOAH LSM makes bias. It is difficult to amend NOAH LSM because the soil, vegetation, and surface condition observations are lack. The most bias of temperature field could be found lower bias near the Yellow Sea and higher bias near the tropic ocean area. It is due to cumulus parameterization and more moist simulation value. The lower soil temperature and wetter soil moisture in the simulation might make air and surface temperature lower than observation over Taiwan. It still needs to improve on simulating the strength of typhoons and stationary front events. Lower soil temperature initiation would make the air and surface temperature lower is due to the interaction between soil and atmosphere. The thermal conduction in soil has time lag in deep soil layer, so the different soil layers have different time intervals for lower temperature values restoring in Taiwan. The lower air temperature over Taiwan would be taken by wind, and makes the temperature field bias display the northeast to southwest wave state.
    Appears in Collections:[大氣物理研究所 ] 博碩士論文

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