为了解雨强历时过程对地表蒸散发的影响作用, 分别采用 IBIS 模型自带的天气发生器和一种基于雨强历时 关系的降尺度模型, 对长白山地区的日降水进行了降尺度模拟计算, 并以计算的小时降水为驱动, 利用 IBIS 模型对 地区蒸散发进行模拟。对比分析的结果表明, IBIS 模型自带的天气发生器模拟的降水强度明显偏低, 导致地表蒸 散发模拟结果偏大, 而雨强历时模型可以较好地模拟降水和蒸散发过程。这说明降水模拟精度的提高有利于促进 地表蒸散发的模拟效果, 进而提高水循环过程的模拟精度。此外, 针对两场不同雨量的降水, 对比分析不同雨强和 历时方案下蒸散发的变化, 指出在日降水量相同的情况下, 在雨强大、 历时短的降水过程中, 地表蒸散发总量较小, 截留蒸发所占的比重较小, 而土壤蒸发和植被蒸腾所占比重较大。

In order to recognize the effects of precipitation intensity and duration on the evapotranspiration, temporal downscaling simulation of daily precipitation in Changbaishan area is conducted using the weather generator of IBIS ( Integrated Biosphere Simulator) model and a precipitation downscaling model based on precipitation intensity and duration. The calculated hourly precipitation is used as the meteorological drive and evapotranspiration is simulated using the IBIS model. The results show that the precipitation intensity simulated by the weather generator of IBIS model is obviously lower, leading to a higher evapotranspi 2 ration, while the results from the precipitation downscaling model match the observation data well. The accuracy of evapotrans2 piration simulation can be improved with the accurate precipitation downscaling. In addition, through the comparison of evapo2 transpiration variation under different schemes of precipitation intensity and duration based on two precipitation events in 2004, stronger precipitation intensity and shorter precipitation duration can decrease the total evapotranspiration and the proportion of canopy interception evaporation, and increase the proportion of soil evaporation and plant transpiration under the same daily pre 2 cipitation.

国家自然科学基金( 51179203) ; 国家水体污染控制与治理科技重大专项课题( 2008ZX07207 2006; 2012ZX07201 2006) ; 国家自然 科学基金青年科学基金项目( 51109222; 51309248; 51309245) ; 中国水利水电科学研究院科研专项( ZJ1224)