The footprint of Asian monsoon dynamics in the mass and energy balance of a Tibetan glacier
The footprint of Asian monsoon dynamics in the mass and energy balance of a Tibetan glacier
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DOI：
10.5194/tc-6-1445-2012
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发表时间：
2012-12
期刊：
影响因子：
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通讯作者：
T. Mölg;F. Maussion;Wei Yang;D. Scherer
中科院分区：
文献类型：
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作者：
T. Mölg;F. Maussion;Wei Yang;D. Scherer
青藏高原偏远山区的冰川范围内的质量和能量平衡的测定仍然很少，在那里实地测量是具有挑战性的。该模型应用程序旨在首次量化印度夏季风（ISM）在季风年周期的各个阶段如何影响整个冰川。我们发现ISM在年际尺度上具有强大而系统的足迹。早（晚）季风的发生导致更高（更低）的交流积累，主要通过吸收的短波辐射的变化减少（增加）可用的消融能量。相比之下，在ISM停止阶段只存在一个弱内存占用。然而，最引人注目的是核心季风季节：当地的质量和能量平衡变率与ISM期间定义大尺度大气变率的活动/中断循环完全分离。然而，我们没有发现ISM对主要季风海子冰川的直接影响，这一点迄今尚未得到承认。
Determinations of glacier-wide mass and energy balance are still scarce for the remote mountains of the Ti- betan Plateau, where field measurements are challenging. Here we run and evaluate a physical, distributed mass bal- ance model for Zhadang Glacier (central Tibet, 30 N) based on in-situ measurements over 2009-2011 and an uncertainty estimate by Monte Carlo and ensemble strategies. The model application aims to provide the first quantification of how the Indian Summer Monsoon (ISM) impacts an entire glacier over the various stages of the monsoon's annual cycle. We find a strong and systematic ISM footprint on the interannual scale. Early (late) monsoon onset causes higher (lower) ac- cumulation, and reduces (increases) the available energy for ablation primarily through changes in absorbed shortwave ra- diation. By contrast, only a weak footprint exists in the ISM cessation phase. Most striking though is the core monsoon season: local mass and energy balance variability is fully de- coupled from the active/break cycle that defines large-scale atmospheric variability during the ISM. Our results demon- strate quantitatively that monsoon onset strongly affects the ablation season of glaciers in Tibet. However, we find no di- rect ISM impact on the glacier in the main monsoon sea- son, which has not been acknowledged so far. This result also adds cryospheric evidence that, once the monsoon is in full swing, regional atmospheric variability prevails on the Tibetan Plateau in summer.