黄河流域1961—2012年蒸散发时空变化特征及影响因素分析

基于黄河流域1 500个0.25°×0.25°网格,应用可变下渗能力模型VIC-3L计算1961—2012年黄河流域水文过程,获得日尺度的实际蒸散发量和潜在蒸散发量数据。运用Mann-Kendall趋势检验方法和Budyko水分能量平衡公式,分析了实际蒸散发量、潜在蒸散发量、蒸散发率和干燥指数的时空变化趋势及蒸散发受水分能量供应条件限制情况。结果表明:总体上实际蒸散发量和潜在蒸散发量呈减小趋势,其中潜在蒸散发量减小趋势显著,但在流域不同区域的增减趋势不同;蒸散发率和干燥指数的变化不明显;黄河流域上游蒸散发主要受能量供应条件限制影响,而中下游受水量供应条件限制影响较大。

Temporal and spatial characteristics of evapotranspiration in the Yellow River Basin during 1961-2012 and analysis of its influence factors

On the basis of 1500 grids of 0. 25°×0. 25°, the VIC(Variable Infiltration Capacity)-3L model was applied to calculate the hydrologic process in the Yellow River River Basin from 1961 to 2012, getting daily actual evapotranspiration(E)and potential evapotranspiration(E_P). Then the Mann-Kendall trend test method and the Budyko water-energy balance formula were applied in analyzing the variational trends of E, E_P, Evapotranspiration ratio(E/P), dryness index(E/E_P), and the influence of water and energy supply on evapotranspiration. The results show that E and E_P have a tendency of decreasing on the whole, and E_P shows a remarkable trend with spatially variety. The evapotranspiration ratio(E/P)and dryness index(E/E_P)do not show obvious change. Evapotranspiration in the upper reaches of the Yellow River Basin was mainly affected by the limitation of energy supply, while the one in the middle and lower reaches of the Yellow River Basin was affected by the limitation of water supply.