Tree-ring-based snowfall record for cold arid western Himalaya, India since A.D. 1460

摘要

Understanding snowfall variations in high-elevation cold arid regions of the western Himalaya is important as snowmelt water is the main source of water to meet the scores of socioeconomic needs. The ground-based observational data, though limited to the last two decades, show decreasing snowfall, raising the concern of looming water scarcity in the region. The tree-ring data of Himalayan cedar from a network of six moisture-stressed sites, where snowmelt water is the sole source of soil moisture for tree growth, were used to develop the November-April snow water equivalent (SWE) extending back to A.D. 1460. The reconstruction revealed persistent severe droughts in the 1780s followed by the 1480s and relatively lesser magnitude droughts in the 1540s-1560s, 1740s, and early twentieth century. The pluvial conditions observed in 1948-1958 and 1986-1996 stand out over any other period of such duration. The SWE reconstruction revealed large-scale spatial coherence with the corresponding month's Palmer Drought Severity Index over the western Himalayan region. Significant relationship observed between SWE reconstruction and January-March Chenab River flow revealed its potential utility in understanding water resource availability in the long-term perspective. Key Points Tree-ring-based snow water equivalent data for western Himalaya Snowmelt water main hydrological resource Snowmelt water significantly associated with July flow of Chenab