Spatio-temporal Variation of Temperature and Precipitation of Sagarmatha Zone, Eastern Nepal.

This study analyses spatial and temporal variability of temperature and precipitation along different physiographic regions (Terai or low land: L, mid-hills: Mh, high-hills: Hh and high Himalaya: H) of Sagarmatha zone, eastern Nepal. Within the approximate 187 km North-South width, elevation of the study area ranges from 80 m a.s.l at Terai in south to 8,848 m a.s.l at the highest peak of the Earth, Mt. Everest in north. Such rapid change in altitude has caused a wide range of climatic conditions in this area. In this study, we have used observed climate data from five meteorological stations located at different elevations, namely Rajbiraj (L: 91m), Okhaldhunga (Mh: 1720m), Salleri (Hh: 2378m), Syangboche (H: 3700m) and Dingboche (H: 4355m) in order to present how temperature and precipitation varies with elevation and time. The spatial distribution of past temperature data (1980 - 2013) shows that annual mean temperature at the higher elevation (H) is increasing at relatively higher rate ( 0.09 °C/yr) than middle and lower elevations. Similarly, annual temperature at middle and higher elevation shows more positive temperature anomalies than at lower elevation which also indicates that the temperature is getting warmer than normal at these regions. Annual precipitation trend in largely fluctuating, however, it shows increasing trend in Mh (5.48 mm/yr) and Hh (3.74 mm/yr) with more positive precipitation anomalies but decreasing trend in the number of rainy days, whereas at lower elevation (L), annual precipitation is decreasing (-8.4 mm/yr) but the number of rainy days is increasing. We also analyzed the spatial and temporal variation in the projected temperature and precipitation data obtained from CORDEX South Asia RCM (Experiment: CCAM-CNRM) at RCP4.5 and RCP8.5 climate scenarios. The results obtained from this study can be used to assess the impact of climate change in the region and devise better mitigation and adaptation strategies and plans.