Deciphering the changes associated with Western Disturbances impacting “Karakoram Anomaly”

Abstract

<p>In contrast to the general retreat of glaciers across the globe, the glaciers of the Karakoram (KR) region of Karakoram-Himalayas (KH) have displayed an anomalous divergent response, with some glaciers remaining either stable or surging. This phenomenon is known as the "Karakoram Anomaly." Although many factors are reported to have control over it, the present study tries to decipher the role of Western Disturbances (WDs) in establishing and sustaining the anomaly. These upper-tropospheric extra-tropical cyclones impact the region during the boreal winter. WDs are the major contributor of winter snowfall over KR, dictating the mass-balance variability of the region, as reported by previous studies. Therefore, to achieve the study's objectives, a tracking algorithm is applied to 39-seasons (1980-2019; Nov-Mar) of the ERA5 reanalysis dataset. Initial simulations suggest that the tracking algorithm has the potential to capture nearly ~90% of the reported tracks accurately in terms of their time of occurrence. Furthermore, the associated statistics generated for tracks passing through KR revealed a ~10% increase in the WD-associated precipitation intensity. The results shall be further analyzed to quantify the contribution of WD-associated snowfall in modulating the regional mass-balance anomaly. Additionally, the various mechanisms involved in WDs' formation and intensification will also be investigated.</p>