过去30年气候变化对黄河源区水源涵养量的影响

黄河源区高寒生态系统具有重要的水源涵养功能。基于改进的LPJ动态植被模型,模拟研究1981-2010年中国黄河源区水源涵养量的时空变化特征,进一步探讨气候要素变化的影响。结果表明：近30年来黄河源区水源涵养量整体略呈减少趋势,减少速率为-1.15 mm/a,区域差异特征体现为大部分地区以减少趋势为主,特别是黄河源区东南部。过去30年黄河源区降水量以及大气水分需求能力的变化是影响生态系统水源涵养量增减的主要气候因素。随着干湿条件不同,两者影响程度各异,降水减少和潜在蒸散增加共同导致黄河源区东南部半湿润地区水源涵养量减少,而降水增加则是北部半干旱地区水源涵养量增加的主要原因。

Ecosystem water conservation changes in response to climate change in the Source Region of the Yellow River from 1981 to 2010

The alpine ecosystem of the Source Region of the Yellow River (SRYR) has a significant water conservation function which represents water cycle within the atmosphere and biosphere. In this paper, ecosystem water conservation (EWC) was modeled by a modified dynamic vegetation model. Based on water balance method, the spatial-temporal changes in EWC and the impacts of climatic change were analyzed in the SRYR during the period 1981-2010. Results indicated that the EWC has a slightly decreasing trend of -1.15 mm/a in the past three decades. Furthermore, the EWC of most regions decreased especially in the southeast of the SRYR. In general, changes in both precipitation and atmospheric moisture demands have explicit influences on the amount and changes of the EWC, and the influences are various in different moisture conditions. In the southeast of the SRYR with sub-humid climate, both decreased precipitation and increased potential evapotranspiration induce the significant negative changes in the EWC. Meanwhile, in the northern part with semi-arid climate, increased precipitation is the main climatic factor leading the EWC to increase.