1981-2010 年气候变化对青藏高原实际蒸散的影响

基于1981-2010 年青藏高原80 个气象台站观测数据, 通过改进的LPJ 动态植被模型, 模拟并分析了青藏高原实际蒸散及其与降水的平衡关系(P-E) 的时空变化。研究结果表明, 在过去三十年来青藏高原气候呈现以变暖为主要特征的背景下, 降水量整体略有增加, 潜在蒸散呈减少趋势, 特别是2000 年以前减少趋势显著;青藏高原大部分地区实际蒸散呈增加趋势, P-E的变化趋势呈西北增加-东南减少的空间格局。大气水分蒸散发能力降低理论上会导致实际蒸散减少, 而青藏高原大部分地区实际蒸散增加, 主要影响因素是降水增加, 实际蒸散呈增加(减少) 趋势的区域中86% (73%) 的降水增加(减少)。

Impact of Climate Change on Actual Evapotranspiration on the Tibetan Plateau during 1981-2010

To quantify the impact of climate change on the evapotranspiration process of alpine ecosystems on the Tibetan Plateau, we performed a series of simulations with the LPJ dynamic vegetation model and 80 meteorological stations from 1981 to 2010. Changes in actual evapotranspiration and the difference between precipitation and actual evapotranspiration (P-E) on the Tibetan Plateau were analyzed. Over the last 30 years, climate change was characterized by significantly increased temperature, slightly increased precipitation and decreased potential evapotranspiration which was significant before 2000. Actual evapotranspiration had increasing trends in most parts of the Tibetan Plateau, and P-E mainly had decreasing trends in southeastern plateau and increasing trends in northwestern plateau. Descending atmospheric water demand would lead to a decreasing trend in actual evapotranspiration; however, it increased in most regions due to more precipitation. Actual evapotranspiration increased (decreased) in most regions where there was 86% (73%) of increased (decreased) precipitation.