钾长石单颗粒高温后红外释光(pIRIR)测年技术最近被应用于青藏高原冰川沉积测年,发现仍存在一定的挑战和问题,其可靠性仍需进一步检验。论文选择中国第四纪冰川测年研究工作较为详尽的地点——天山乌鲁木齐河源地区,探索冰水沉积钾长石...钾长石单颗粒高温后红外释光(pIRIR)测年技术最近被应用于青藏高原冰川沉积测年,发现仍存在一定的挑战和问题,其可靠性仍需进一步检验。论文选择中国第四纪冰川测年研究工作较为详尽的地点——天山乌鲁木齐河源地区,探索冰水沉积钾长石单颗粒测年的可行性。在红五月桥附近一个冰水透镜体中采集了2个样品,尝试了单颗粒石英光释光和钾长石后红外释光测试。结果表明,石英单颗粒释光信号弱,无法获得有效年代。剂量恢复实验表明,钾长石pIRIR_(110)、pIRIR_(170)适用于该区域样品测年。使用归一化中位数绝对偏差(nMAD)法剔除部分离散信号,并利用中心年龄模型(central age model,CAM)计算的IR_(110)校正后的年龄与pIRIR_(170)年龄相近。两个样品的pIRIR_(170)年龄分别为21.9±2.4 ka和22.1±2.4 ka,两者误差范围内一致,且与上望峰冰碛其他年龄结果相吻合。研究验证了钾长石释光测年应用于冰水沉积中的可行性,为山地冰川沉积测年提供了参考。展开更多
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...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5.91×108 m^(3)(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。展开更多
Climate change and rising temperatures are accelerating the rate of deglaciation in the Hindu Kush Karakoram Himalaya(HKH)ranges,leading to the formation of new glacial lakes and the expansion of existing ones.These l...Climate change and rising temperatures are accelerating the rate of deglaciation in the Hindu Kush Karakoram Himalaya(HKH)ranges,leading to the formation of new glacial lakes and the expansion of existing ones.These lakes are often vulnerable to failure,posing a significant threat to downstream communities and infrastructure.Therefore,a comprehensive assessment of Glacier-Lake Outburst Flood(GLOF)hazards and risk assessment is crucial to evaluate flood runout characteristics and identify settlements and infrastructure that are exposed and vulnerable to floods,aiding in the development and implementation of risk reduction strategies.This study aims to simulate a GLOF event induced by the Shisper glacier lake in northern Pakistan,using the HEC-RAS,and to assess its impact on settlements,infrastructure,and agricultural land.For the hydrometeorological analysis of the GLOF event,topographic data from unmanned aerial vehicles(UAVs),stream profiles,discharge data,Manning's roughness coefficient(n),and land use/land cover(LULC)were analyzed using HEC-RAS and geographic information system(GIS).During the GLOF event on May 7,2022,a maximum water depth of 6.3 m and a maximum velocity of 9.5 m/s were recorded.Based on the runout characteristics of this event,vulnerability and risk assessments have been calculated.The physical,social,and environmental vulnerabilities of the at-risk elements were evaluated using the analytical hierarchy process(AHP)and integrated with the hazard data to develop a risk map.The study identified the areas,infrastructure and settlements susceptible to GLOF hazard to support the development and implementation of targeted and evidence-based mitigation and adaptation strategies.展开更多
文摘钾长石单颗粒高温后红外释光(pIRIR)测年技术最近被应用于青藏高原冰川沉积测年,发现仍存在一定的挑战和问题,其可靠性仍需进一步检验。论文选择中国第四纪冰川测年研究工作较为详尽的地点——天山乌鲁木齐河源地区,探索冰水沉积钾长石单颗粒测年的可行性。在红五月桥附近一个冰水透镜体中采集了2个样品,尝试了单颗粒石英光释光和钾长石后红外释光测试。结果表明,石英单颗粒释光信号弱,无法获得有效年代。剂量恢复实验表明,钾长石pIRIR_(110)、pIRIR_(170)适用于该区域样品测年。使用归一化中位数绝对偏差(nMAD)法剔除部分离散信号,并利用中心年龄模型(central age model,CAM)计算的IR_(110)校正后的年龄与pIRIR_(170)年龄相近。两个样品的pIRIR_(170)年龄分别为21.9±2.4 ka和22.1±2.4 ka,两者误差范围内一致,且与上望峰冰碛其他年龄结果相吻合。研究验证了钾长石释光测年应用于冰水沉积中的可行性,为山地冰川沉积测年提供了参考。
文摘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5.91×108 m^(3)(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。
基金the Higher Education Commission of Pakistan for supporting the study through the CRG-CPEC-130 project。
文摘Climate change and rising temperatures are accelerating the rate of deglaciation in the Hindu Kush Karakoram Himalaya(HKH)ranges,leading to the formation of new glacial lakes and the expansion of existing ones.These lakes are often vulnerable to failure,posing a significant threat to downstream communities and infrastructure.Therefore,a comprehensive assessment of Glacier-Lake Outburst Flood(GLOF)hazards and risk assessment is crucial to evaluate flood runout characteristics and identify settlements and infrastructure that are exposed and vulnerable to floods,aiding in the development and implementation of risk reduction strategies.This study aims to simulate a GLOF event induced by the Shisper glacier lake in northern Pakistan,using the HEC-RAS,and to assess its impact on settlements,infrastructure,and agricultural land.For the hydrometeorological analysis of the GLOF event,topographic data from unmanned aerial vehicles(UAVs),stream profiles,discharge data,Manning's roughness coefficient(n),and land use/land cover(LULC)were analyzed using HEC-RAS and geographic information system(GIS).During the GLOF event on May 7,2022,a maximum water depth of 6.3 m and a maximum velocity of 9.5 m/s were recorded.Based on the runout characteristics of this event,vulnerability and risk assessments have been calculated.The physical,social,and environmental vulnerabilities of the at-risk elements were evaluated using the analytical hierarchy process(AHP)and integrated with the hazard data to develop a risk map.The study identified the areas,infrastructure and settlements susceptible to GLOF hazard to support the development and implementation of targeted and evidence-based mitigation and adaptation strategies.
