Identifying mechanisms driving spatially heterogeneous glacial mass-balance patterns in the Himalaya, including the ‘Karakoram anomaly’, is crucial for understanding regional water resource trajectories. Streamflows dependent on glacial meltwater are strongly positively correlated with Karakoram summer air temperatures, which show recent anomalous cooling. We explain these temperature and streamflow anomalies through a circulation system—the Karakoram vortex—identified using a regional circulation metric that quantifies the relative position and intensity of the westerly jet. Winter temperature responses to this metric are homogeneous across South Asia, but the Karakoram summer response diverges from the rest of the Himalaya. We show that this is due to seasonal contraction of the Karakoram vortex through its interaction with the South Asian monsoon. We conclude that interannual variability in the Karakoram vortex, quantified by our circulation metric, explains the variability in energy-constrained ablation manifested in river flows across the Himalaya, with important implications for Himalayan glaciers’ futures.

中文翻译：

---

喀喇昆仑温度和冰川融化受区域大气环流变化的驱动

确定驱动喜马拉雅山空间异质性冰川质量平衡模式（包括“ Karakoram异常”）的机制，对于理解区域水资源轨迹至关重要。依赖于冰川融水的水流与喀喇昆仑州夏季气温强烈正相关，这表明最近出现了异常降温。我们通过循环系统-Karakoram涡旋解释了这些温度和流量异常，该循环系统使用区域循环量度来识别，该量度量化了西风射流的相对位置和强度。在南亚，冬季对这一指标的温度响应是均匀的，但喀喇昆仑山脉的夏季响应与喜马拉雅山的其他地区有所不同。我们表明这是由于喀喇昆仑涡与南亚季风的相互作用引起的季节收缩。我们得出的结论是，用我们的循环量度量化的喀喇昆仑涡旋中的年际变化解释了在喜马拉雅山脉中河流流动中表现出的能量受限消融的变化，这对喜马拉雅冰川的未来具有重要意义。