NOAA/WDS Paleoclimatology - Northwest Himalaya 400 Year Standardized Precipitation Index Reconstruction

Droughts are recurring phenomena in the north-western Himalaya causing severe socio-economic hardships. Our understanding on temporal and spatial occurrence of such extreme droughts in long-term perspective is constrained due to limited short-term weather records. Towards fulfilling such a large data void we developed a network of ring-width chronologies of Himalayan cedar from seven moisture stressed high elevation sites in Kishtwar, Jammu and Kashmir. Moisture responsive ring-width chronologies were used to develop the annual Standardized Precipitation Index (SPI from previous year June to current year May (SPI12-May)) extending back to AD 1613. The SPI reconstruction revealed annual to decadal-scale variability in droughts, which strikingly were more frequent and of larger magnitude during AD 1760s-2017 in comparison to the earlier part of the reconstruction (AD 1613-1750s). Our SPI12-May record revealed strong consistency with other tree-ring-based hydrological records from the western Himalaya. Spatial correlation analyses revealed strong linkage of the SPI with Tropical Pacific Ocean surface temperature.