基于遥感的巴音布鲁克高寒草原蒸散发量模拟

发布时间：2018-07-10 13:04

本文选题：MODIS + 实际蒸散发　；参考：《新疆大学》2017年硕士论文

【摘要】：利用MODIS数据的地表温度、归一化植被指数和地表反照率等参数,结合气象站的观测和DEM数据,基于SEBAL模型模拟了巴音布鲁克高寒草原2000年、2007年和2014年植被生长季,共21天的日尺度地表实际蒸散发量。利用FAO P-M公式对模拟结果进行了地面验证,并运用变异系数法和相关分析法讨论了蒸散发的空间格局、时间变化特征、空间格局异质性和相关性。结果表明:1.SEBAL模拟值和FAO P-M公式计算值的R2为0.7047,均方根误差为0.3676;不同生长阶段的平均相对误差依次为:生长后期冻结期生长前期生长期。2.空间格局上,全区蒸散发有明显的高、低值中心。受土壤湿度和植被覆盖的影响,高值区主要在大、小尤路都斯盆地和低山带。而低值区在焉耆盆地和山脉的高海拔带;同时,受人工种植和灌溉的影响,焉耆绿洲内有零星的高值点。3.(1)时间序列上,区域蒸散发水平2000年2007年2014年;同时,蒸散发呈季节性波动,波动幅度依次为:2000年2007年2014年。(2)季节变化上,三年间全区蒸散发平均值最高的时间均为7月12日,即夏季蒸散发水平最高。而平均值最低的时间为9月14日或10月16日,即秋季蒸散发水平最低;同时,全区蒸散发标准差最高的日期均为7月12日,即夏季蒸散发离散程度最高。而标准差最低的日期在9月14日或10月16日,即秋季蒸散发离散程度最低。(3)从生长季的角度看,蒸散发在冻结期较低,进入生长前期迅速升高,生长期最大,生长后期急剧下降。4.空间异质性方面,全区蒸散发以高波动变化为主,不同变异程度的面积比例:高波动变化无法确定相对较高的波动变化中等波动变化相对较低的波动变化低波动变化;同时,高波动变化区主要在大、小尤路都斯盆地,是天然植被季节性盛衰所致。焉耆绿洲的高波动变化与农作物不同物候期迥异的叶面积状况和耕地土壤湿度有关。5.空间相关性方面,蒸散发与地表温度为负线性相关,不同生长阶段的相关水平:生长后期生长期生长前期冻结期;在冻结期、生长前期和生长后期,蒸散发与NDVI为负线性相关,相关水平:生长后期生长前期冻结期,而在生长期,蒸散发与NDVI为正线性相关;蒸散发与地表反照率为正线性相关,相关水平为:冻结期生长后期生长前期生长期。
[Abstract]:Using the parameters of MODIS data, such as surface temperature, normalized vegetation index and surface albedo, combined with meteorological station observation and Dem data, the vegetation growing seasons of Bayinbrook alpine grassland in 2000, 2007 and 2014 were simulated based on SEBAL model. A total of 21 days of actual surface evapotranspiration on a daily scale. The simulation results were verified by FAO P-M formula, and the spatial pattern, temporal variation characteristics, spatial pattern heterogeneity and correlation of evapotranspiration were discussed by coefficient of variation method and correlation analysis. The results showed that the R2 of the simulated value of SEBAL and the calculated value of FAO P-M formula was 0.7047, the root mean square error was 0.3676, and the average relative error of different growth stages was as follows: the growth period of the early growth stage of the late growth stage was frozen period. In the spatial pattern, the evapotranspiration of the whole area has obvious high and low value centers. Under the influence of soil moisture and vegetation cover, the high value areas are mainly in the large, small Luduz basin and low mountain zone. However, the low value area is in the high elevation zone of Yanqi basin and mountain range, at the same time, affected by artificial planting and irrigation, there are sporadic high value points. (1) in the time series, the regional evapotranspiration level is 2000 and 2014; at the same time, The seasonal fluctuation of evapotranspiration is as follows: 2000, 2007 and 2014. (2) in the seasonal variation, the mean time of the regional evapotranspiration is the highest in July 12, that is, the highest level of the summer evapotranspiration. The lowest mean time is September 14 or October 16, that is, autumn evapotranspiration level is the lowest, and the highest standard deviation of evapotranspiration in the whole region is July 12, that is, summer evapotranspiration dispersion is the highest. However, the lowest standard deviation date is September 14 or October 16, that is, autumn evapotranspiration dispersion is the lowest. (3) from the point of view of growing season, evapotranspiration is low in freezing period, rising rapidly in early growth period, and maximum in growth period. At the late stage of growth, there was a sharp decline. In terms of spatial heterogeneity, the evapotranspiration of the whole region is dominated by high fluctuation, and the area ratio of different variation degree: the high fluctuation change can not determine the relatively high fluctuation change, the middle fluctuation change is relatively low fluctuation change, the low fluctuation change, at the same time, The high fluctuation area is mainly in the large and small Luduz basin, which is caused by the seasonal rise and fall of natural vegetation. The variation of high fluctuation in Yanqi oasis is related to the different leaf area of different phenological periods of crops and the soil moisture of cultivated land. In terms of spatial correlation, there was a negative linear correlation between evapotranspiration and surface temperature. The correlation levels of different growth stages were as follows: freezing period in early growth stage, and negative linear correlation between evapotranspiration and NDVI in freezing period, early growth period and late growth period. Correlation level: at the early growth stage, the evapotranspiration was positively linearly correlated with NDVI, and there was a positive linear correlation between the evapotranspiration and the surface albedo.
【学位授予单位】：新疆大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S812

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