Measurements on Solar Energy Resources in the Mt. Everest Region

Abstract

Research on solar radiation in the Mt. Everest region provides great interests for the strategies of solar energy utilization, climate change and environmental sustainability etc. We present measurement results of global horizontal irradiance, solar spectral irradiance and solar UV irradiance performed with the Dutch CMP11 Pyranometers, the German RAMSES Hyperspectral Irradiance Sensors and the Norwegian NILU-UV Irradiance Meters respectively in the Mt. Everest region during 2008 to 2017. The results show that the solar energy resources are extremely rich in that area, the daily maximum of global horizontal irradiance levels are even frequently exceed the solar constant value of 1368W/m2 during monsoon season, from May to August in that region. The highest daily maximum value reached 1500 W/m2 occurred on July 13, 2017. The annual average of the daily global horizontal irradiance is about 18.4 MJ/m2/d, the daily global horizontal irradiance varies from 13.8 to 23.9 MJ/m2/d, indicates that there are abundant solar energy in that alpine zone. The instruments record that even during the winter time (October to January) more than 15 days of each month are absolute clear days, it shows 28 clear days in November of 2016. It points out that more solar energy can be existed during the winter time due to dry season. The solar spectral irradiance was performed for the first time in this special environment presenting the characteristics of solar spectrum over the region. It reveals not only how abundant the spectral irradiance is, but also rich information about the atmospheric composition over the sky. It is well known that the solar UV radiation strongly impacts on the ecological environment and human health. The measurement results of solar UV dose rates as well as their impact factors (ozone and cloud) during the period of 2008 to 2017 are also presented. Satellite data are also used to see how the solar irradiance is distributed over the Himalayan region in summer, including Mt. Everest.