Analysis of Land Surface Energy and Water Cycle Changes in Naqu Region of Qinghai-Tibet Plateau during 2005-2016

Abstract

In order to improve the integrity of the research on the thermal conditions of the Qinghai-Tibet Plateau and the plateau energy cycle, and strengthen the understanding of the climate change and water cycle in the Nagqu area, this article uses the 2005—provided by the Naqu Alpine Climate and Environmental Observation and Research Station of the Northwest Institute of Eco- Environmental Resources, Chinese Academy of Sciences. In 2016, the hour by hour high-resolution data set of atmospheric, soil and eddy observations analyzed the surface radiation budget, energy conversion, energy balance, and energy closure in the Naqu region of the Qinghai-Tibet Plateau. The following conclusions are obtained: compared with sunny days, the diurnal variation of the various components of surface energy in Nagqu in cloudy weather is very irregular, and the reflectivity of cloudy weather becomes larger. In cloudy weather, the thermal process between the surface and the atmosphere and deep soil is more violent than short-wave radiation. The albedo at each moment of the day in winter is greater than that in summer because of the unique surface characteristics of the plateau. Both summer and winter sensible heat flux and latent heat flux have the same diurnal variation trend as net radiation. The sensible heat flux and latent heat flux in summer are significantly higher than those in winter, but the latent heat flux changes more significantly with the seasons. When considering the soil heat storage term, the energy closure degree in summer is 0.301 and that in winter is 0.701. The energy closure degree in winter is significantly higher than that in summer.