基于MODIS和ERA-Interim的安徽省地表蒸散发及其受植被覆盖度影响研究

Study on the surface evapotranspiration and its responses to vegetation coverage of Anhui Province based on MODIS and ERA-Interim data

本文旨在基于面尺度探究安徽省2000-2014年地表蒸散发(evapotranspiration,ET)的时空变化特征,并定量分析气象因子、非气象因子对ET的贡献,重点研究植被覆盖度变化对ET的影响。利用蒸散发产品(MOD16A2)、植被指数产品(MOD13A3)、气象资料,采用像元二分模型、回归分析和相关分析等方法进行了研究。结果表明:2000-2014年安徽省年际地表ET呈减少趋势,空间分布上表现为南高北低;15年间研究区内植被覆盖度整体呈增长趋势,区域整体处于中高植被覆盖度等级,多年来植被高覆盖度占比均大于36%;研究时序内安徽省ET变化受非气象因子影响更加显著,贡献度为68%,植被覆盖度作为重要的非气象因子与ET逐月相关系数为0.8567,两者相关性具有区域差异,须因地制宜地改善区域水文生态环境。

We analyzed the spatial-temporal variations of the actual surface evapotranspiration(ET)of Anhui Province and explored its correlations with the meteorological factors and non-meteorological factors,especially the influence of vegetation coverage change on ET.We applied the sub-pixel model,regression analysis and correlation analysis methods with the MODIS gridded 1000 m monthly evapotranspiration product(MODIS16A2),monthly vegetation index product(MODIS13A3)and meteorological data during the period of 2000-2014.The results indicated that the annual evapotranspiration of Anhui Province showed a downward trend with an increase in space from north to south during 2000-2014.However,the vegetation coverage had an increasing trend in the study area during the 15 years.The whole area was at medium to high vegetation coverage level with more than 36%of high vegetation coverage level over the years.The changes of ET in Anhui Province were more significantly affected by non-meteorological factors with a relative contribution degree of 68%during the study time series.Moreover,the monthly correlation coefficient between vegetation coverage and ET was 0.8567,which varied with regional differences.In order to effectively improve the regional hydrological and ecological environment,we need to adapt to local conditions.