基于MOD16产品的海拉尔流域蒸散发时空分布特征研究

MOD16 products-based study on spatio-temporal distribution characteristics of evapotranspiration in hailarhe river watershed

旱涝灾害频发与流域水量平衡的变化密切相关,而地表蒸散量作为流域水量平衡中的重要环节,研究陆面蒸散发时空分布在旱涝灾害监测和预警等方面具有重要的意义。基于MOD16全球蒸散发产品,以海拉尔河流域为研究区域,通过相关性分析和线性趋势分析,统计分析了2001—2018年海拉尔河流域地表的实际蒸散发(AET)和潜在蒸散发(PET)的时空分布特征和变化趋势。结果表明:(1)海拉尔河流域2001—2018年多年平均AET、PET的空间分布特征自东向西表现出较为显著的递减和递增空间变化规律,流域AET的波动范围为218.7~718.1mm,PET的波动范围为548.2~1190.6 mm;(2)不同土地覆被类型下多年平均AET值由大到小依次为有林地、高覆盖度草地、旱地、沼泽地、城乡居民用地、中覆盖度草地,多年平均PET值由大到小依次为中覆盖度草地、沼泽地、城乡居民用地、高覆盖度草地、旱地、有林地。(3)地表AET、PET年内变化具有一定的季节性,流域春、夏、秋、冬四季的AET多年均值分别为76.8 mm、273.1 mm、61.9 mm、21.6 mm,PET多年均值分别为288.0 mm、580.8 mm、168.7 mm、22.5 mm,AET和PET的多年均值由大到小依次均是夏季>春季>秋季>冬季。

The frequent occurrence of flood and drought disasters is closely related to changes in the watershed water balance,and land surface evapotranspiration plays an important role in the watershed water balance.Based on the MOD16 global evapotranspiration products and taking Hailarhe River Water as the study area,the spatio-temporal distribution characteristics and variation trends of the surface actual evapotranspiration(AET)and potential evapotranspiration(PET)of Hailarhe River Watershed from 2001 to 2018 are statistically analyzed herein.The results show that(1)the spatial distribution characteristics of the annual mean AET and PET in the watershed from 2001 to 2018 exhibit the spatial variation laws of significant progressive decrease and progressive increase from the east to the west with the fluctuating range of AET of 218.7~718.1 mm and the fluctuating range of PET of 548.233~1190.55 mm within the watershed;(2)the annual mean AET values from large to small for different land cover types are forest land,high-coverage grassland,dry land,marsh land,urban and rural residential land,medium-coverage grassland in turn,while the annual mean PET values from large to small are medium-coverage grassland,marshland,urban and rural residential land,high-coverage grassland,dry land,and forested land;(3)certain seasonalities are there for AET and PET values,while the annual mean values of AET in spring,summer,autumn and winter are 76.855 mm,273.151 mm,61.974 mm and 21.686 mm respectively and the annual mean values of PET in spring,summer,autumn and winter are 288.019 mm,580.788 mm,168.712 mm,22.469 mm respectively as well;for which the annual mean values of AET and PET from large to small are summer>spring>autumn>winter in turn.