中国冻土对气候变化的脆弱性

Vulnerability of Frozen Ground to Climate Change in China

冻土的脆弱性是指冻土对气候变化的脆弱性,是冻土易受气候变化,尤其是温度变化不利影响的程度.研究冻土对气候变化的脆弱性是提高对自然生态系统、工程系统、生态-社会-经济系统对冻土变化影响的脆弱性的认知,科学适应冻土变化诸种影响的前提和基础.基于科学性与实际相结合的原则、全面性与主导性原则、可操作性原则,以暴露度、敏感性与适应能力为标准,遴选构建了我国冻土脆弱性评价指标体系.借助RS与GIS技术平台,使用空间主成分方法,构建了冻土脆弱性指数模型,在区域尺度上综合评价了冻土的脆弱性.依据自然分类法,将冻土脆弱性分为潜在脆弱、轻度脆弱、中度脆弱、强度脆弱与极强度脆弱5级.结果表明:总体上我国冻土以中度脆弱为主,但青藏高原多年冻土对气候变化尤为脆弱;冻土脆弱性具有显著的地域分布特点,青藏高原、西部高山、东北多年冻土区脆弱性相对较高,季节冻土区相对较低.与季节冻土相比,多年冻土对气候变化更脆弱.在当前升温幅度条件下,冻土脆弱程度主要取决于冻土的地形暴露与冻土对气候变化的适应能力.

Vulnerability of frozen ground is the vulnerability of frozen ground to climate change.The frozen ground system is susceptible to adverse effects of climate change,especially temperature variation.Study of the frozen ground vulnerability is the basic for improving the understanding of the vulnerabilities of the natural ecological,engineering,and ecological social economic systems to the impacts of frozen ground change,scientifically adapting to these effects.A frozen ground numerical model is developed using spatial principle component analysis supported by remote sensing and geographical information system technologies.The model contains nine factors describing topography, climate and frozen ground characteristics.The vulnerability of frozen ground to climate change is evaluated for the period of 1961-2007on a regional scale.The vulnerability is graded into five levels： potential,light,medial,heavy and very heavy, following Natural Breaks Classification.The spatial distribution of frozen ground vulnerability is analyzed and the factors influencing the vulnerability are discussed.The results show that overall vulnerability of frozen ground in China is at medial level.However,the permafrost on the Tibetan Plateau is very vulnerable,at heavy and very heavy vulnerable level.Compared with seasonal frozen ground,permafrost to climate change is more vulnerable.Under the conditions of current temperature rise,the frozen ground vulnerability is mainly explained by topographical exposure and adaptive capacity of frozen ground to climate change.