SRES情景下青藏高原生态功能保护区水源涵养功能的变化研究

Water Conservation Function Changes in Ecological Reserves on the Tibetan Plateau Under SRES Scenarios

预估分析未来水源涵养功能对气候变化的响应,对制定适应气候变化策略和措施具有科学指导意义。本文以青藏高原国家级生态功能保护区水源涵养功能为研究对象,利用SRES A2和B2情景下区域气候模式的气候情景数据,通过改进的LPJ动态植被模型,模拟了1981-2100年生态功能保护区水源涵养功能对气候变化的响应。通过分析未来近期、中期和远期研究区水源涵养功能相对基准时段(1981-2010年)的动态变化,结果表明未来SRES情景下,研究区总体上水源涵养功能在近期以增强为主,主要受降水量增加的影响;而未来中期和远期水源涵养功能受水分实际蒸散增加的影响而减弱的可能性则更大,并随着增温幅度增加而减弱程度加强。

It has been recognized that climate change has significant impacts on water conservation across the Tibetan Plateau. Analysis of the response of water conservation function to future climate change is important for planning strategies to adapt to climate change. The objective of the present study was to evaluate the regional scale impacts of climate change on the water conservation function （indicated by the difference in precipitation and actual evapotranspiration） of national ecological function reserve regions. Water conservation function responses to climate change from 1981-2100 were estimated based on the modified dynamic vegetation model LPJ, together with a regional climate model under SRES A2 and B2 emission scenarios. Results show that in the near term, the water conservation function is likely to enhance relative to the baseline period in most of the national ecological function reserve regions on the Tibetan Plateau, mainly due to increased precipitation. However, in the mid-term and long term, the water conservation function of most regions would likely decrease, resulting from positive changes in actual water evapotranspiration. Water conservation function is predicted to decrease by 30% in the Source Region of the Yangtze River. Water conservation functional change is directly impacted by variations in precipitation and actual evapotranspiration, which represents complicated interactions among soil, vegetation and atmosphere under climate change.