Arid Zone Research ›› 2024, Vol. 41 ›› Issue (1): 24-35.doi: 10.13866/j.azr.2024.01.03

• Weather and Climate • Previous Articles     Next Articles

Biophysical effects of the different underlying factors on land the surface temperature in the Qinghai Lake Basin

LI Yongguang(),YUAN Guanghui()   

  1. Key Laboratory for Aerosol-Cloud-Precipitation of China Meteorological Administration, Nanjing University of Information Science and Technology, Nanjing 210044, Jiangsu, China
  • Received:2023-05-27 Revised:2023-07-30 Online:2024-01-15 Published:2024-01-24

Abstract:

The micrometeorological elements, radiation budget, and surface turbulent data at two sites with land cover types of subalpine shrub and warm steppe in the Qinghai Lake Basin in 2021 were compared to investigate the differences in the land-atmosphere interaction between the various surface types and the biophysical effects of Land Use/Land Cover Changes on surface temperature. June to September was the growing, and January to April was the nongrowing season. There were marked differences in surface, air, and soil temperatures and relative humidity between the two sites. In the growing and nongrowing seasons, the peak temperatures of the topmost 5 cm of the soil in warm steppe were 295.4° K and 277.6° K, while those in subalpine shrub were only 288.6° K and 275.4° K, respectively. During the growing season, the peak surface and air temperatures of the warm steppe were 298.8° K and 288.2° K, and that of the subalpine shrub were 292.5° K and 286.5° K, respectively. In the nongrowing season, there was no significant difference in the daytime surface temperatures between the two stations, and the night surface temperature of the warm steppe was 2.8° K higher than that of the subalpine shrubs. The subalpine shrub had lower surface, air, and soil temperatures than the warm steppe; these differences between the two stations were more evident during the growing season, and the variations in the relative humidity in the nongrowing season were more obvious. Based on the Direct Decomposed Temperature Metric, the influence of radiation budget and surface energy distribution between the two sites regarding the surface temperature differences was analyzed. The subalpine shrub had cooling effects compared with the warm steppe. In the daytime of the growing and nongrowing seasons, the short wave radiation term promoted the cooling effect of the subalpine shrub, and the sensible, latent, and surface-soil heat flux terms inhibited the cooling effect of the subalpine shrub. At night, the radiation and nonradiation terms promoted the cooling effect of subalpine shrubs in the growing season. In contrast, the sensible heat flux terms had a warming effect, and the other terms demonstrated a cooling effect in the nongrowing season. The main contributing factors to subalpine shrub cooling during the daytime were shortwave radiation, surface-soil heat flux, and sensible heat flux terms. The main contributing factor at night was the surface-soil heat flux term.

Key words: land use and land cover change, surface temperature, radiation budget, surface soil heat flux, turbulent flux, Qinghai Lake Basin