Meteorological Analysis of high altitude Automatic Weather Station data from the Everest Region

Abstract

This study presents a high-altitude meteorological variables in the Everest region since October 2010 to December 2018 by using different seven automatic weather stations (AWS) data ranging in elevation from 4200 to 6400 m a.s.l. Some are still operating at Mera and Changri Nup glacier site in the Inkhu/Hunga and Khumbu valley. Four stations are in the glacier and three are near the glacier measures air temperature, wind speed and direction, air pressure, change in surface height of snow, incoming shortwave and long wave radiation, and outgoing shortwave and long wave radiation. Annual, seasonal, and diurnal observed meteorological variables are compared between the sites. Since 2013-14 to 2017-18 air temperature at Mera, Naulek and Changri-Nup glacier sites found highly increased where the winter temperature growth found highest. There is strong influence of solar radiation and wind pattern on diurnal cycle of temperature and vapour pressure. Similarly, local topography and local scale circulations also affect wind speed and precipitation cycle. Extreme event have a significant role in non-monsoonal seasonal cumulative precipitation. The comparison of temperature gradient at Mera glacier site is found different in all scale, higher negative in winter and least negative in monsoon. The calculated zero degree isotherm is found 5000 m a.s.l in all over the monsoon and increased up to 7000 m a.s.l indicates most of the monsoonal precipitation at this elevation is in liquid form. And in monsoon the 6.11hPa is oline is above 5000 m a.s.l which suggest that the glacier in this area loses a lots of mass/energy by evaporation and sublimation in monsoon.