三江源区气候变化及其环境影响研究综述

Review of Climate Change and Its Environmental Influence on the Three-River Regions

三江源区地处青藏高原腹地,是中国长江、黄河和澜沧江三大河流的发源地,并且作为全球气候变化的"敏感区",气候变化无疑会对该区域的气候、环境和水资源产生深刻影响。本文综述了三江源区近50~60年气候、环境和水资源变化的事实,主要认知如下:(1)三江源区总体呈现升温趋势,升温速率约为0.33℃·(10a)^-1,是青藏高原同期的1.2倍。(2)三江源区降水总体呈现增加趋势,趋势约为6.653 mm·(10a)^-1,为青藏高原同期降水增加率的71%。(3)三江源区年最低和最高气温呈现显著增加趋势,且冷季增幅大于暖季。降水量的变化趋于稳定,降水变率减小,严重干旱或暴雨事件均呈减少趋势。(4)三江源区南部积雪日数最多且呈显著增加趋势,黄河源区整体上呈现积雪初日推迟、终日提前、积雪期缩短和积雪日数减少趋势。(5)在升温影响下,冻土严重退化,并引起沼泽湿地的发育,在降水增加和气温升高引起的融水增加的双重影响下,三江源区湖泊沼泽持续扩张。(6)尽管三江源区降水总体呈增加趋势,但径流变化存在较大的区域差异,长江源区径流显著增加,而黄河源区则为减少趋势,直门达和香达水文站径流变化倾向率分别为6.69×10^8m^3·(10a)^-1和1.1×10^8m^3·(10a)^-1。最后,对气候变化影响下水循环变化及其对环境和水资源影响的研究现状进行了讨论,并呼吁加强大气水文过程的耦合研究,量化气候变化、人类活动及陆气耦合多圈层相互作用的研究以加强其影响区域气候环境和水循环的认识,为三江源区适应气候变化和青藏高原生态文明建设提供参考。

The Three-river sources regions(TRSR),located on the Qinghai-Xiang Plateau(QXP),are the source regions of Yangtze,Yellow and Lancang River.Under the background of global climate change,the QXP was considered as the"sensitive region"and the"promoter region"of climate change,which will definitely affect the regional climate,environment,and water resources on the TRSR.This paper reviews the facts of variations of climate,environment and water resources in the recent 5~6 decades.The main conclusions are as follows:(1)Air temperature increased on the TRSR with a trend of 0.33℃·(10 a)^-1,which is 1.2 times of the rate on QXP.(2)Precipitation increased on the TRSR with a trend of 6.653 mm·(10 a)^-1,but the trend was 71%of the QXP.(3)The minimum and maximum air temperature increased significantly,with the trend in the cold seasons higher than the warm seasons.(4)Snow days on the south of the TRSR increased,but decreased on the source region of the Yellow river.(5)Under the climate warming,the permafrost degraded,in combing with the precipitation enhancement,the lakes and the wetlands were developed.(6)Although precipitation on the TRSR enhanced,runoff shows different trends,with it increased on the sources of Yangtze river(the trend of runoff in Zhimenda station is 6.69×10^8 m^3·(10 a)-1),and decreased on the Yellow river(the trend of runoff in Xiangda station is 1.1×10^8 m^3·(10 a)-1).At last,the water cycle changes under the warming and its influences on water resources were discussed,according to which it is important to do more investigations on the multi-sphere interactions to distinct the contribution to water resources from climate change and human activities.These kinds of knowledge will benefit for the TRSR to adapt climate change and supply references for the TRSR park construction.