全球变暖背景下中亚兴都库什、喀喇昆仑及天山气候变化研究进展

Research advances in climate change over Hindu Kush,Karakoram and Tianshan Mountains in Central Asia under global warming

中亚兴都库什、喀喇昆仑及天山山脉(HKT)是气候变化敏感区,其在全球变暖背景下的气候变化对区域生态和经济系统的稳定性及可持续发展有重要意义。目前对中亚高海拔地区的研究多集中于局部区域,有关HKT地区气候变化的综合对比分析较为缺乏。本文对HKT地区现代气候变化的相关研究成果进行简单梳理和回顾,重点总结了HKT地区气候变化特征、影响机制及其与全球变暖的联系。结果表明:(1)近60 a,HKT地区不同区域气候的时空特征存在差异,从时间上看,天山的年均温及年降水量均呈上升趋势,而兴都库什-喀喇昆仑山的年均温呈不显著增加趋势,其年降水量变化趋势不稳定;从空间上看,HKT地区山脉南坡气温高于北坡,但北坡降水量高于南坡,且天山南北坡年降水均呈上升趋势。(2)HKT地区的气候变化除了受西风环流、南亚印度季风及局地条件等影响外,还受到北大西洋涛动和厄尔尼诺-南方涛动等大尺度气候模态的调制,如兴都库什-喀喇昆仑山脉在NAO正(负)位相和ENSO暖(冷)位相降水趋于增加(减少)。

Background, aim, and scope The Hindu Kush, Karakoram and Tianshan Mountains(HKT) in Central Asia are sensitive to climate change, and their responses under current global warming are of great significance for the stability and sustainable development of regional ecological and economic systems. However, the existing studies on these high-altitude regions of Central Asia are mostly focused on specific areas, lacking the comprehensively comparative analysis over the whole HKT region. Materials and methods This paper presents and summarizes the research advances in modern climate change in HKT region, with a special focus on the features, dynamical mechanisms and their relationship with global warming. Temperature and precipitation data from Climatic Research Unit, CRU TS4.04 are chosen and the linear trend method is used in the analysis.Results In the past 60 years, the temporal and spatial characteristics of climate change in different regions of HKT are distinct. The mean annual temperature and annual precipitation over Tianshan Mountain show an increasing trend. The mean annual temperature of Hindu Kush-Karakoram Mountain increases insignificantly and the variation of annual precipitation is not stable. Spatially, the temperature over the southern slope of the HKT Mountains is higher than that over the northern slope, but the precipitation over the northern slope is higher. The annual precipitation on both slopes of the Tianshan Mountains shows an increasing trend.Discussion Climate change and occurrence of extreme weathers in HKT region are affected by a combination of factors. The climate of the Tianshan Mountains is not only affected by large-scale circulation such as westerly circulation and monsoon, but also by local conditions, such as the increase of local oasis area and irrigation,and the increase in temperature in mountainous areas. The climate of the Hindu Kush-Karakoram Mountains is mainly influenced by the mid-latitude westerly gyre, the South Asian Indian monsoon and the intra-Asian high pressure system effect. Precipitation in the Hindu Kush-Karakoram area increases(decreases) during the positive(negative) phase of NAO and the warm(cold) phase of ENSO. Conclusions In the past 60 years, there have been some differences in the temporal and spatial characteristics of temperature and precipitation in different HKT regions. The studies on climate change in the HKT region can not only deepen the understanding of the regional climate response to global change, but also provide scientific basis for sustainable development of human society and ecological environment. Recommendations and perspectives The mechanisms of climate change in HKT region are still not clear and future researches are eagerly required. It is necessary to evaluate the effects of local recycling and large-scale circulation on mountainous climate in different regions and altitudes of HKT. The potential impact of human activities should be also taken into account.