*2.1. Study Area*

Nepal is a country located on the southern slopes of the central Himalayas at 26.36◦–30.45◦N latitude and 80.06◦–88.2◦E longitude (Figure 1). Approximately 80% of the country comprises hills and mountains, and the remaining 20% is flatlands. The elevation of the country rises abruptly from the southern lowlands to the higher Himalayas giving rise to complex topography, weather and climate. Physiographically, the country is broadly classified into Terai (lowlands), hills and mountains [42,48]. The south Asian monsoon system and westerlies regulate the climatology of the country, with maximum precipitation in summer season (80%, June–September) followed by spring (March–May), autumn (October–November), and winter seasons (December–February) [49]. Usually, the monsoon advances from the east of the country in early June and promotes rainfall to the whole country within ten days [50]. During the winter, under the westerly-controlled climate in the western region, the country only receives about 3% of its annual precipitation [51]. Pre- and post-monsoon seasons are generally dry and hot, while the winter is cold and precipitation is generally in the form of snow, especially in high-elevation mountain areas [52].
