【摘要】 天山冰川融水是下游绿洲生态和社会经济发展的命脉。显著增温使天山冰川消融加剧,这种变化深刻改变了区域的水资源配置,定量评估其变化显得尤为重要。本文聚焦天山地区冰川,通过多源数据（冰川编目和ASTER物质平衡数据）对模型参数进行更精准的集成约束,利用月尺度的度日模型对天山地区的冰川物质平衡及冰川径流进行了模拟。结果显示:1961—2020年天山冰川物质平衡呈亏损状态(-0.36 m w.e.·a^-1),以1990年为界,1990年之后冰川物质平衡较之前减少0.15 m w.e.·a^-1,在更高的物质亏损驱动下,致使1990年之后年均冰川径流量增加5.91×10⁸m³（10.58%）;对天山冰川变化的敏感性分析发现气温上升0.5℃,冰川物质平衡减少0.16 m w.e.·a^-1,而降水增加10%,冰川物质平衡增加0.03 m w.e.·a^-1,即天山冰川物质亏损主要归因于气温的升高;最后讨论了近60年大气环流转型对冰川物质平衡的影响,发现天山冰川物质平衡在1990年之前主要受高空气旋控制,空气绝热上升气温下降,使其亏损呈较小状态,而1990年之后受高空反气旋环流控制,加剧了下沉气流绝热增温进而导致天山冰川物质的持续较大亏损。更多还原

【Abstract】 The Tianshan Mountains are the most extensive in the global arid zone,with glaciers developing at high altitudes.The glacial meltwater of the Tianshan Mountains provides valuable freshwater resources for the ecological and socio-economic development of downstream oases.Significant warming has intensified the ablation of Tianshan glaciers,altering their morphology and profoundly changing the regional water allocation.Therefore,quantitative assessment of glacier changes in the Tianshan region was critical.In this paper,focusing on all glaciers in the Tianshan region,we simulated the glacier mass balance and glacier runoff by driving a monthly-scale mass balance model using temperature and precipitation data from ERA5.At the same time,the glacier area data of the Tianshan region from two glacier inventories and the mass balance results from ASTER were used to calibrate and validate the model parameters of individual glaciers.The results showed that the glacier mass balance in the Tianshan region was in a state of deficit from 1961 to 2020,with a multi-year average value of-0.36 m w.e.·a^-1.With 1990 as the boundary,the average annual glacier mass balance after 1990 was-0.43 m w.e.·a^-1,which was 0.15 m w.e.·a^-1 less than before 1990.The Tarim Basin had the most minor glacier mass loss due to the lowest mean annual temperature at the basin scale.In contrast,the Turpan-Hami Basin had the most severe loss of glacier mass balance due to the highest mean annual temperature and lowest annual precipitation.Regarding spatial changes in the glacier mass balance,most areas of the Tianshan region were below 0 m w.e.·a^-1,i.e.,most of the Tianshan region was in a state of mass deficit in the past.However,glacier mass accumulation and smaller deficits were concentrated in the western and central parts of the Tianshan region,while the eastern part faced more severe deficits.Glacier runoff in the Tianshan region increased throughout the study period,with a multi-year average value of 58.86×10⁸ m³.However,driven by a higher mass deficit,resulting in an increase in the average annual glacier runoff after 1990 by 5.91×10⁸ m³（10.58%）.Among the four basins,the Tarim Basin had the largest glacier runoff,while the Turpan-Hami Basin had the smallest glacier runoff due to the relative minimum of glaciers.Sensitivity analysis of glacier changes in the Tianshan region found that for every 0.5℃ increase in temperature,the glacier mass balance decreased by an average of0.16 m w.e.·a^-1.In contrast,for every 10% increase in precipitation,the glacier mass balance increased by an average of 0.03 m w.e.·a^-1.Although the climate of the Tianshan region showed a warming and humidification trend,a comprehensive analysis of the value of changes in temperature and precipitation revealed that the effect of increasing temperature on glacier change was significantly more significant than that of increasing precipitation.Finally,the effect of atmospheric circulation transition on the glacier mass balance in the past 60 years was discussed.It was found that the Tianshan glacier mass balance was mainly controlled by high-altitude cyclones before 1990,with the adiabatic rise of the air and the decrease of the surface temperature,which led to a relatively small deficit.After 1990,the control of high-altitude anticyclonic circulation exacerbated the adiabatic warming of the sinking airflow,resulting in a sustained and larger deficit of glacier mass in the Tianshan region.By calibrating and validating the parameters of a single glacier and accurately modelling the glacier mass balance and runoff across the entire Tianshan region,we not only deepened our understanding of the overall characteristics of glacier changes in the Tianshan region but also provided methodological references for regional water resource management and future prediction studies.更多还原