Regional and seasonal variability of rainfall characteristics in Nepal

Abstract

Regional and seasonal variability of rainfall characteristics was investigated in Nepal on the southern slopes of the Himalayas using long-term daily rainfall data Cluster analysis was applied to define subregions in Nepal based on the seasonal progression of precipitation. The results identified four subregions. The characteristics of the seasonal progression of daily average precipitation indicate the significance of premonsoon rainfall in April and May in the eastern part of Nepal. Comparisons of seasonal changes in rainfall characteristics in each subregion showed that increases in rainfall amount, number of days on which rain falls, and rainfall intensity occur during the summer monsoon season with a peak in July, expect in the western mountainous region. In the western region and northern part of the eastern mid-hill regioa rainfall amount and rainfall intensity increase in the winter season. Moreover, a significant change in rainfall intensity occurs in the eastern Terai region between the summer and winter season.