Abstract
The Koshi river basin sustains the livelihoods of millions of people in the upstream and downstream areas of the basin. People rely on monsoon rainfall for agricultural production, hydropower generation and other livelihood activities. Climate change is expected to have serious implication on its environment. To reduce the adverse impacts of disasters and to better understand the implication of climate change for the sustainable development, initiative in this regard is necessary. Analysis of past meteorological trends and future climate projections can give us a sense of what to expect and how to prepare ourselves and manage available resources. In this paper, we have used a high-resolution climate model, viz., Providing REgional Climates for Impacts Studies (PRECIS), to project future climate scenario over the Koshi river basin for impact assessment. Three outputs of the Quantifying Uncertainties in Model Prediction (QUMP) simulations have been used to project the future climate. These simulations were selected from the 17-member Perturbed Physics Ensemble (PPE) using Hadley Centre Couple Model (HadCM3) based on the IPCC SRES A1B emission scenario. The future projections are analysed for three time slices 2011-2040 (near future), 2041-2070 (middle of the century) and 2071-2098 (distant future). Despite quantitative wet and cold bias, the model was able to resolve the seasonal pattern reasonably well. The model projects a decrease in rainfall in the near future and a progressive increase towards the end of the century. The projected change in rainfall is non-uniform, with increase over the southern plains and the middle mountains and decrease over the trans-Himalayan region. Simulation suggests that rainy days will be less frequent but more intense over the southern plains towards the end of the century. Further, the model projections indicate significant warming towards the end of the century. The rate of warming is slightly higher over the trans-Himalayan region during summer and over the southern plains during winter.
Highlights
The Himalayan region is highly influenced by monsoon rainfall
The major sources of water in the Hindu Kush Himalaya (HKH)—snow and ice reserves are considered vulnerable to climate change [9] [10]
Over the southern plains, summer monsoon is expected to increase from the base period towards the end of the 21st century
Summary
The Himalayan region is highly influenced by monsoon rainfall. About 80% of the annual total rainfall occurs during the monsoon season (June-September) in the eastern parts of the Himalayas [1], but the role of monsoon decreases as it proceeds west and the influence of westerly winter disturbances becomes more prominent. The increased emissions of greenhouse gases and short-lived climate pollutants (SLCP) are modifying short-term and seasonal climate variability [4] Such changes can have profound impact on sectors like agriculture, water resources and human health in the Himalayan region [5] [6]. This study attempts to examine future changes in climate over the Koshi river basin using three simulation outputs from the regional climate model PRECIS based on the SRES A1B scenario [19]. APHRODITE’s (Asian Precipitation - Highly - Resolved Observational Daily Integration Towards Evaluation http://www.chikyu.ac.jp/precip/) gridded data has been taken as the base data for evaluation of the seasonal rainfall simulation These gridded datasets are publicly available at a resolution of 0.25 ̊ for the monsoon Asian domain (60 ̊E 150 ̊E and 15 ̊N - 55 ̊N). The Princeton data is of coarse resolution so for the present study, we have used daily temperature range from this dataset and applied it to APHRODITE's mean daily temperature to build maximum and minimum temperatures of 0.25 ̊ resolution
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
