Intensified Western Disturbances sustained the Karakoram Anomaly in recent decades?

Glaciers across the globe have been retreating under the impacts of global warming, the Himalayas being no exception. However, the glaciers of the Karakoram (KR) region of Karakoram-Himalayas (KH) have displayed an anomalous divergent response by either remaining stable or even slightly surging. This phenomenon is known as the "Karakoram Anomaly." Although many mechanisms and manifestations are reported to have control over it, the present study unravels the role of Western Disturbances (WDs) in establishing and sustaining the anomaly. These upper-tropospheric mid-latitude cyclones travel eastward embedded in subtropical westerly Jetstream (STWJ), impacting the region during the boreal winter and dictating the mass-balance variability of the region. The present study applied a tracking algorithm to three global reanalysis datasets for 39-seasons (1980-2019; Nov-Mar). Composite statistics for tracks passing through KR revealed a ~10% increase in the WD-associated precipitation intensity. WDs were found to provide ~65% of the total seasonal snowfall in the region, establishing them as the primary source of accumulation. Moreover, their contribution to snowfall volume over the core glaciated regions of Karakoram has increased by ~27% in recent decades. A simultaneous decline of about ~17% in the precipitation received from non-WD sources was also observed. Results suggest that the enhanced intensity of WDs is a by-product of increased baroclinic instability, the poleward shift of the STWJ mean latitudinal position, and an eastward shift in their core genesis zone.