关键词: 地表蒸散发, 东江流域, 时空特征, MOD16, ET, PET

Abstract: Evapotranspiration plays a key role in maintaining the energy balance and water circulation in a basin. On the basis of MOD16 remote sensing dataset, we analyzed the temporal and spatial distribution characteristics of surface evapotranspiration in Dongjiang River Basin on inter-annual and annual scales, and researched the temporal and spatial characteristics of surface evapotranspiration of different land cover types. Results illustrated that: (1) The amount of evapotranspiration (ET) in the midstream of Dongjiang River Basin is larger than that in the downstream and the upstream in sequence, while the amount of potential evapotranspiration (PET) follows the order of downstream > midstream > upstream. (2) On inter-annual (one decade) scale, ET fluctuates little, whereas PET fluctuates remarkably, both presenting rising trends after 2014. (3) On annual scale, ET displays a single peak, mounting to the top in September and concentrating in May-October, while dropping to the valley in February and remaining low from December to next February. The mean value of ET in Autumn is the largest, followed by that in Summer, Spring, and Winter in sequence. (4) In terms of land use types, the annual ET on bare land is the largest, followed by cultivated field, urban area, grassland, and woodland in sequence, while PET shows an order of urban area > cultivated field > grassland > woodland > bare land. The monthly ET has a same regularity in general. In winter, the coefficient of variation of ET is high and in summer is low. The coefficient of variation of ET on woodland is low and the degree of dispersion is small. The research results are of great significance for the prevention of drought and waterlogging in the Dongjiang River Basin.

Key words: surface evapotranspiration, Dongjiang River Basin, temporal and spatial characteristics, MOD16, ET, PET