Premonsoon precipitation variability in Kumaon Himalaya, India over a perspective of ∼300 years

Abstract

Variability in premonsoon precipitation, which has direct impact on rabi crop productivity in the Himalayan region, is not well understood in a long-term perspective, largely due to the paucity of weather data. We developed an annually resolved FebruaryeMay (FM) precipitation record extending back to AD 1730 using tree-ring width data of Himalayan cedar for the first time from the Kumaon region, eastern sector of the western Himalaya, India. The FM precipitation reconstruction, capturing 58% of the variance in instrumental data over the calibration period (1901e1968), is the strongest so far from the Indian region. The reconstruction revealed inter-annual to decadal-scale variations in precipitation anomalies. Twentieth-century decadal-scale droughts occurred in the 1920s, and 1960s to early 1970s, and pluvials in the 1910s and 1980s. However, the droughts in 1920e1924 were the most severe of any other comparable period in last three centuries. Pre-instrumental droughts of the 1740s, 1780s, and 1840s were widespread in a large part of the western Himalaya. The drying tendency noted in the last two decades, which is widespread in the western Himalaya and western Nepal, in view of increased hydrological demand is alarming, and could cause severe water stress in the region unless adaptive measures are taken.