基于MOD16产品的淮河流域实际蒸散发时空分布

Spatio-temporal distribution of terrestrial evapotranspiration in Huaihe River basin based on MOD16 ET data

蒸散发是陆面过程中的重要环节,联系着陆面水循环和地表能量平衡.淮河流域地处中国南北气候过渡带,对淮河流域实际蒸散量时空变化的研究,有助于深入理解中国气候过渡带水循环对全球气候变化的响应.应用遥感技术对淮河流域MOD16_ET数据进行精度验证,并分析2000-2014年淮河流域蒸散发时空分布特征.结果表明：MOD16_ET产品在淮河流域内的精度总体上符合要求;淮河流域多年平均蒸散发的空间分布整体上呈南高北低,季节蒸散量的空间分布与年蒸散量的空间分布大体一致;近15 a淮河流域平均的实际蒸散量变化范围为531.7～634.0 mm,且存在不显著的下降趋势,实际蒸散量的季节变化大致呈单峰型分布,且季节变化较为明显,夏季（257.2 mm）〉春季（143.7 mm）〉秋季（120.7 mm）〉冬季（66.6 mm）;淮河流域西北部,夏、秋、冬三季的季节蒸散量变化速率对年蒸散量变化速率的贡献较大;淮河流域东部,春季的蒸散量变化速率占年蒸散量变化速率的比重较大.研究结果对于淮河流域内水资源短缺问题的解决、有限水资源的合理利用以及旱涝灾害的监测和预警有着重要的意义.

Terrestrial evapotranspiration（ ET） is the key connection of a wide array of Earth system processes,which links water cycles and energy balances over land. The Huaihe River basin is located in the transition climate zone from North China to South China. In order to further understand the response of water cycles to climate change,global or regional,spatial and temporal analysis of ETin the Huaihe River basin is essential.Remote sensing technology has obvious advantages in monitoring evapotranspiration of heterogeneous surface.Based on verification of the accuracy of MOD16 ET,in this paper,the spatial and temporal characteristics of the Huaihe River basin were analyzed entirely. It is found that（ 1） the magnitude and spatial distribution of MOD16 ETover the Huaihe River basin are basically reasonable;（ 2） the multi-year averaged annual ETcorresponds with the sum of four seasonal ETof the basin and has characterized by higher value in south and lower value in north;（ 3） in the last 15 years,the average annual ETof whole basin has ranged from 531. 7 to 634. 0 mm,with an indistinctive downward tendency; seasonal variation of EThas been approximately unimodal,which changes obviously with reason： 143. 7 mm in spring,257. 2 mm in summer,120. 7 mm in autumn and 66. 6 mm in winter;（ 4） spatially,in the northwest,annual ETchanging rate in grid scale is mainly dominated by summer,autumn and winter ETchanging rate,but in the east annual ETchanging rate is dominated by spring ETchanging rate primarily. The research results have important significance for howto solve the shortage of water resources,howto utilize the limited water resources,and howto monitor and forewarn flood and drought disaster.