The Small Earth Nepal, Nepal.
The Small Earth Nepal, Nepal; Nepal Academy of Science and Technology, Nepal.
Environ Res. 2020 Jun;185:109430. doi: 10.1016/j.envres.2020.109430. Epub 2020 Mar 28.
It's unequivocal that the global climate is changing, including the rise in atmospheric temperature and variability in amount and pattern of precipitation, and the rate of temperature change in the Himalayan region is higher than the global average. Since precipitation and temperature are the major driving factors of water resources in the Himalayas both upstream and downstream regions, it is important to understand theimpacts of climate change in water resource availability in the future. In this study, we analyzed the historical hydro-climate data and developed a suitable ensemble of the Coordinated Regional Downscaling Experiment (CORDEX) climate models for the Karnali River Basin (KRB) in western Nepal and assessed the future water availability in different climate scenarios using a semi-distributed catchment scale hydrological model the Soil and Water Assessment Tool (SWAT). The climate data analysis shows that the atmospheric temperature is rising throughout the basin but there is high spatial variability in precipitation trend. The historical river discharge data analysis do not show any significant trend, however, there is some inter-annual variability. Future projection shows that the annual precipitation amount will increase compared to the baseline so does the river discharge. However, this increase is not uniform for all seasons. The post-monsoon season having the lowest observed precipitation will get lesser amount of precipitation in the future and the river discharge also follows the same trend. These anomalies play a crucial role in determining the future water availability for agriculture, hydropower, ecosystem functioning and its services availability to the people living in the KRB as well as in the downstream region.
毫无疑问，全球气候正在发生变化，包括大气温度的上升和降水总量及模式的可变性，喜马拉雅地区的温度变化速度高于全球平均水平。由于上下游地区的降水和温度是喜马拉雅水资源的主要驱动因素，因此了解未来气候变化对水资源可利用性的影响非常重要。在本研究中，我们分析了历史水文气候数据，并为尼泊尔西部的卡纳利河流域 (KRB) 开发了一组协调区域降尺度实验 (CORDEX) 气候模型，以评估不同气候情景下的未来水资源可用性使用半分布式流域尺度水文模型土壤和水评估工具 (SWAT)。气候数据分析表明，整个流域的大气温度都在上升，但降水趋势存在高度的空间变异性。历史河川径流量数据分析并未显示出任何显著的趋势，但存在一些年际变化。未来预测显示，与基准线相比，年降水量将增加，河川径流量也将增加。然而，这种增加并不是所有季节都均匀的。后季风季节是观测到的降水最少的季节，未来的降水量将会更少，河川径流量也会遵循同样的趋势。这些异常在确定 KRB 及下游地区的农业、水电、生态系统功能以及对生活在那里的人们的服务可用性的未来水资源可用性方面起着至关重要的作用。
