新疆玛纳斯河流域蒸散发时空分布格局研究

Spatiotemporal Variation of Evapotranspiration in the Manas River Basin in Xinjiang

【目的】分析玛纳斯河流域基于MODIS数据的蒸散发时空分布特征及影响因素,为玛纳斯河流域的水资源分配、生态环境的保护、社会生产等方面提供参考。【方法】以玛纳斯河流域为研究区,对玛纳斯河流域2000—2018年地表实际蒸散发的年际和年内时空变化规律用镶嵌、重采样、栅格计算及线性回归等方法进行了研究。【结果】不同土地利用的平均蒸散发量从大到小依次为林地(418.65 mm)>水域(302.36 mm)>耕地(257.32 mm)>未利用地(222.00 mm)>建设用地(218.10 mm)>草地(207.04 mm)。ET在夏季达到高峰,其次为春季、秋季,冬季最少;蒸散发趋势在季节尺度方面主要表现为冬季对年蒸散发变化趋势影响不大,但夏季对年蒸散发的影响比较突出。【结论】玛纳斯河流域多年ET均值在16.08~598.77 mm/a,表现出显著的空间差异性,整体上呈南部高、中部次之、北部最低,流域上中游高、下游低的分布格局。

【Background and objective】Evapotranspiration(ET)is an important component in the hydrological cycle and is affected by many biotic and abiotic factors.Understanding its spatiotemporal variation in a region is hence central to help improve its water management.The objective of this paper is to analyse the spatiotemporal variation of ET across the Manas River Basin in Xinjiang of China.【Method】The analysis was based on data measured between 2000 and 2018.ET were obtained from the 500 m MOD16 ET product and the meteorological data measured from the basin;we considered five spatial resolutions and the time scale in the analysis was seasonal.From spatiotemporal distribution of ET in the region,we calculated its response to land use types,temperature and precipitation,using the means of mosaic,resample,grid calculation,linear regression and trend analyses.【Result】The annual average ET in the basin varied from 16.08 to 598.77 mm/a.Seasonally,the average ET in spring,summer,autumn and winter was 55.29 mm,102.02 mm,50.98 mm and 28.45 mm,respectively.The impact of land usage on ET can be ranked in the order of woodland>water body>cultivated land>spare land>construction land>grassland.For all land use types,ET peaked in summer,followed by spring,with winter being the least.The spatiotemporal variations in both ET and precipitation followed the same trend,and the correlation coefficient between them was 0.67.There was a weak but positive correlation between ET and air temperature.【Conclusion】Spatial variation of ET across the Manas River basin was significant.Temporally,ET was the greatest in summer and the least in winter;spatially,ET was high in the middle,and low in the south and north of the region.Along the river,ET was high in the middle reaches and low in the upper reaches.