Contrasting changes of snowfall in response to Temperature and Rainfall over two distinct geographic ranges of the Himalayas: A study using long-term observations
Snow is a major source of water and its monitoring is important for hydrological applications. It provides a large amount of meltwater to various rivers such as Indus, Ganges and Brahmaputra in the Himalayan region. Significant changes in snowfall variability play a pivotal role in climate as well as socioeconomic development. The present study investigates the temporal variability of snowfall, temperature and rainfall over Nubra (Latitude: 34.53o-35.67o N; Longitude: 76.75o-77.81o E) and
... athi (Latitude: 30.33o-31.45o N; Longitude: 78.15o-79.47o E) basins in the Himalayan region using 30 years of data (1991–2020). The High Asia Reanalysis (HAR) and Climatic Research Unit (CRU) data were used to study the snowfall and maximum temperature variabilities respectively over the study basins. For rainfall, gridded rainfall data from India Meteorological Department is used. We have studied the annual and monthly variability of daily snowfall, temperature and rainfall over the two basins. Our analysis shows the declining trend (-2 mm/decade) of snowfall over the Nubra basin and slight increasing trend (0.12 mm/decade) in Bhagirathi basin from 2004. The monthly time series in maximum temperature anomaly shows a positive trend with a maximum anomaly found to be around 2K during the winter period. From the rainfall analysis, an increasing trend in annual rainfall is observed, especially Nubra basin show notable increase. Further, warming of the troposphere is found to be ~ 2–3 K, which is another important factor for reduction in snowfall. Thus positive trends in maximum temperature, rainfall and warming troposphere are the controlling factors for the declining (increasing) trend in snowfall over the Nubra (Bhagirathi) basins. Further, we have carried out the WRF simulation for the time series of snowfall. Thus, the present study shows simultaneous changes in snowfall, temperature and rainfall over the Himalayan region and assumes importance in climatic applications.