本文選題：實際蒸散量 + 遙感�。� 參考：《西北農(nóng)林科技大學(xué)》2015年碩士論文

【摘要】：水資源分布格局變化和生態(tài)系統(tǒng)息息相關(guān),而蒸散量作為水文循環(huán)和水資源分配利用的重要依據(jù),影響全球或區(qū)域的氣候、生態(tài)和農(nóng)業(yè)生產(chǎn)。研究區(qū)域?qū)嶋H蒸散量,可以為水資源的高效利用和分配提供理論依據(jù)。黃土高原屬于我國水土流失嚴重和生態(tài)環(huán)境脆弱之最的區(qū)域,氣候從半濕潤、半干旱漸變至干旱,年均降水量從東南向西北遞減,土壤從重土壤、中土壤變化到沙土,植被從喬木、灌木向草原過渡。本研究在黃土高原中部選取一條樣帶,運用MODIS數(shù)據(jù)和國內(nèi)外廣泛運用的SEBAL模型估算區(qū)域?qū)嶋H蒸散量,分析退耕還林(草)工程實施以來黃土高原實際蒸散量的演變趨勢。以2000年、2004年、2008年、2012年四年的MODIS數(shù)據(jù)、DEM數(shù)據(jù)和氣象資料為基礎(chǔ),反演地表特征參數(shù),計算各地表通量,估算黃土高原樣帶區(qū)域日蒸散和生長季蒸散情況。使用改進的Biome-BGC模型計算的實際蒸散量與SEBAL估算的實際蒸散量進行對比驗證,評價遙感估算實際蒸散量的準確性。得到如下主要研究結(jié)果:(1)退耕還林草工程實施以來,植被覆蓋度在整體呈上升趨勢,其中2000年植被覆蓋度為54.8%,2003年上升至61.3%,2007年達到最大值65.3%,之后植被覆蓋度隨年降水的變化在較高水平波動。(2)研究區(qū)實際蒸散量年內(nèi)變化呈“單峰”特征,日實際蒸散量平均值從90日至310日的變化趨勢是:先由大約1mm/d,逐漸增加至5mm/d,再減少至1mm/d;月實際蒸散量平均值從4月的50 mm/m逐漸增加至7月的300 mm/m,再減少至10月的30mm/m。實際蒸散量年際變化趨勢是從2000年逐漸增加,至2008年達到最大值,2012又有所降低。(3)實際蒸散量呈現(xiàn)由東南向西北減少的空間分布特征,四個分區(qū)2000~2012年的變化趨勢為:荒漠帶生長季實際蒸散量基本不變,草原帶和森林—草原帶的生長季實際蒸散量先增后減,森林帶的生長季實際蒸散量一直下降。四個區(qū)實際蒸散量對退耕還林(草)工程的響應(yīng)不同。
[Abstract]:The change of distribution pattern of water resources is closely related to ecosystem, and evapotranspiration, as an important basis of hydrological cycle and water resources distribution and utilization, affects the climate, ecology and agricultural production of the whole world or region. The study of regional evapotranspiration can provide theoretical basis for efficient utilization and distribution of water resources. The Loess Plateau is the region with the most serious soil erosion and fragile ecological environment in China. The climate changes from semi-humid, semi-arid to arid, the annual precipitation decreases from southeast to northwest, the soil changes from heavy soil to sandy soil. Vegetation transitions from trees and shrubs to grasslands. In this study, a sample belt was selected in the middle of the Loess Plateau, and the actual evapotranspiration of the Loess Plateau was estimated by using MODIS data and the widely used SEBAL model at home and abroad, and the evolution trend of the actual evapotranspiration of the Loess Plateau since the implementation of the conversion of cropland to Forest (Grass) Project was analyzed. Based on the MODIS data of 2000, 2004, 2008 and 2012, Dem data and meteorological data, the surface characteristic parameters were retrieved, the surface fluxes were calculated, and the daily evapotranspiration and the growing season evapotranspiration in the Loess Plateau transect region were estimated. The actual evapotranspiration calculated by the improved Biome-BGC model is compared with the actual evapotranspiration estimated by SEBAL to evaluate the accuracy of remote sensing estimation of the actual evapotranspiration. The main research results are as follows: (1) since the implementation of the project of returning cropland to forest and grass, the vegetation coverage has been on the rise as a whole. The vegetation coverage was 54.8% in 2000, increased to 61.3% in 2003, reached a maximum of 65.3% in 2007, and then the change of vegetation coverage with annual precipitation fluctuated at a higher level. The average daily actual evapotranspiration increased from 90 to 310 days, gradually increased from about 1 mm / d to 5 mm / d, then decreased to 1 mm / d, and the monthly average of actual evapotranspiration gradually increased from 50 mm/m in April to 300 mm / m in July and then decreased to 30 mm / m in October. The annual variation trend of actual evapotranspiration increased gradually from 2000 to reach the maximum in 2008 and then decreased in 2012) the actual evapotranspiration decreased from southeast to northwest. The change trend of the four zones from 2000 to 2012 is as follows: the actual evapotranspiration of the desert zone is basically unchanged, the actual evapotranspiration of the grassland zone and the forest-grassland zone increases first and then decreases, and the actual evapotranspiration of the forest belt decreases continuously in the growing season. The response of the actual evapotranspiration of the four districts to the conversion of farmland to forest (grass) projects is different.
【學(xué)位授予單位】：西北農(nóng)林科技大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：S161.4

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相關(guān)期刊論文 前1條

1 楊永民;馮兆東;周劍;;基于SEBS模型的黑河流域蒸散發(fā)[J];蘭州大學(xué)學(xué)報(自然科學(xué)版);2008年05期

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本文編號：1884270