天山西部过去500年积雪变化的树轮记录

Mountain snow cover is an important water source for arid areas. However, large amounts of snow can lead to destructive avalanches, floods, traffic interruptions, or even the collapse of buildings. The Tianshan Mountains comprise the largest mountain range in arid Central Asia, which is called the “wet island” of Central Asia. Snow cover change has an important impact on the development of ecological environment and socio-economic development in Xinjiang. The climate of the Tianshan Mountains is dominated by westerly winds and it plays an important role in global climate change research. It is vital to understand the past climatic changes in this area and to explore possible influence mechanisms regarding the sustainable use of the regional water resources. Most of the Tianshan Mountains are covered with snow in winter, and the heavy snow, snowstorms, avalanches, and snowmelt floods in spring can bring great economic losses and even threaten human survival. The western Tianshan Mountains in Xinjiang represent a populated area that is undergoing rapid development of agricultural and economic. On the other hand, it is also one of the areas with the most abundant snow resources in Xinjiang and the most serious snow calamity. Comprehending the long-term snow cover change in the region is important significance. . This study plans to collect new samples of Schrenk spruce (Picea schrenkiana Fisch. et Mey) in typical snow cover area of the western Tianshan Mountains, to develop 15 tree-ring width chronologies and 2 stable isotope chronologies. Further, analyze the relationship between the key parameters of the snow cover (maximum snow depth, snow cover area, snow pressure, snow water equivalent) and tree-ring chronologies, and explore the physiological mechanism of snow cover influence tree growth. Then, we will reconstruct and analyze the snow cover change over past 500 years in the western Tianshan Mountains, and extract the historic snow cover disaster events, further clarify the response and feedback laws of long-term snow cover on climate change. Finally, we will understand the relationship between long-term snow cover changes and external forcing and atmospheric circulation systems at global and regional scales, to reveal the possible impact mechanisms of long-term snow cover changes. This study provides basic data for understanding the long-term snow cover changes in the Tianshan Mountains, it help for the rational utilization of water resources, meteorological disaster prevention and reduction, and early warning of natural disasters.

天山作为“中亚水塔”，其冰雪资源是新疆的固体水库，积雪变化对新疆生态环境和社会经济发展有着重要影响。天山西部是新疆积雪资源最丰富和积雪灾害最严重的地区之一，理解该区域积雪长期变化具有重要的现实意义。本研究计划收集已有树轮年表，并在典型积雪区域新采集雪岭云杉（Picea schrenkiana Fisch. et Mey）树轮样本，新建立15个树轮宽度年表和2个树轮稳定同位素序列，分析树轮宽度和稳定同位素对最大积雪深度、积雪面积、雪压等关键参数的响应规律，探讨树木生长与积雪的内在联系及生理学意义；重建和分析天山西部过去500年积雪变化特征和规律，提取历史积雪灾害事件，明晰积雪对气候变化的响应与反馈规律；理解积雪长期变化与全球和区域尺度外强迫和大气环流系统的联系，揭示其可能的影响机制。该研究为天山山区积雪长期变化研究提供基础数据，为新疆水资源管理、气象防灾减灾和自然灾害早期预警提供科学依据。

天山作为“中亚水塔”，其冰雪资源是新疆的固体水库，积雪变化对新疆生态环境和社会经济发展有着重要影响。天山西部是新疆积雪资源最丰富和积雪灾害最严重的地区之一，理解该区域积雪长期变化具有重要的现实意义。本研究在天山西部采集了20个样点的500多棵树的1000多根样芯，基于树轮气候研究方法，建立了15条树轮宽度年表、2条树轮稳定碳同位素序列以及2条树轮稳定氧同位素序列；分析了整个伊犁河-巴尔喀什湖流域树木径向生长、树轮稳定碳氧同位素与温度、降水及主要积雪参数的响应关系；基于树轮宽度和树轮稳定氧同位素，分别重建了新疆伊犁地区过去500年最大积雪深度变化和哈萨克斯坦伊犁阿拉套1850年以来的降雪变化。主要研究结论：1）新疆积雪主要分布在西北部的阿勒泰到伊犁沿线，伊犁河谷是主要降雪中心，年均最大积雪深度为27cm；2）上年冬季和当年夏季的降水对整个伊犁-巴尔喀什湖流域雪岭云杉的径向生长都有重要影响，径向生长对积雪呈明显的空间差异，存在自西向东的弱-强-弱趋势。这种空间差异主要与区域降水量有关；在降水较多的地区，降雪对树木的生长几乎没有影响，而在降水量有限的地区，冬季降雪可能成为树木径向生长的主要限制性因子。积雪变化没有显著影响树轮稳定碳同位素分馏，但伊犁阿拉套高山区降雪是树轮氧同位素的主要限制性因子；3）过去500年天山西部伊犁地区冬季积雪最大深度变化特征为：16世纪天山西部积雪相对较多，17世纪积雪较少，18世纪偏多，19世纪至20世纪中期最大积雪深度持续偏少，1980年代以来，最大积雪深度偏深，1920年代以来，积雪深度持续增加，尤其是20世纪末至21世纪，积雪深度增幅指数上升。区域冬季降雪水汽可能来自大西洋，并通过西风传输。依托本项目，共发表研究论文9篇，其中SCI收录5篇；实用新型专利1项。本研究可为干旱区气象防灾减灾和农牧业生产提供科学基础。