北京市2005~2015年植被覆盖变化对蒸散发量的影响

Impact of Land Use Change on Evapotranspiration in Beijing from 2005 to 2015

为更准确了解蒸散发量(ET)时空分布及其随土地利用变化的规律,以MOD16数据为基础,探讨不同土地利用类型及其相互间转化对北京市蒸散耗水的影响。结果表明,2005~2015年间,北京市约有2587.69km^2的面积发生了土地利用类型的转变,其中变化最多者为林地转变为耕地,达213.57km^2;北京市植被覆盖区域多年ET平均值为406.63mm,北京市ET空间分布呈西北山区高、东南平原低的特点,且不同植被类型的ET大小不同,其中林地最大,草地次之,耕地最小;在2005~2015年,北京市ET呈上升趋势,速率为8.64mm/a,总耗水量的增加速率为4881.09×104 m3。植被覆盖减少和气象因素变化的综合作用导致北京市的蒸散耗水呈逐年上升趋势。

In order to understand the spatial and temporal distribution of evapotranspiration and land use change more accurately,based on MOD16 data,this paper discusses the impact of different land use types and their transformation on evapotranspiration water consumption in Beijing City.The results showed that from 2005 to 2015,there were 2 587.69 km^2 of land use change in Beijing,among which forest land was converted to cultivated land,reaching 213.57 km^2;The average annual ETof vegetation coverage area in Beijing was 406.63 mm.The spatial distribution of ETin Beijing was high in the Northwest Mountainous area,low in the Southeast plain,and the ETsize of different vegetation types was not the same.In the same way,forest land was the largest,grassland was the second,and cultivated land was the smallest;ETincreased in Beijing from 2005 to 2015 at a rate of 8.64 mm/a,and the total water consumption increased at a rate of48.810 9 million m3.The evapotranspiration water consumption in Beijing is increasing year by year due to the combined effect of the decrease of vegetation cover and the change of meteorological factors.