关键词: 稳定边界层高度, 计算方法, 影响因子, 塔克拉玛干沙漠

Abstract:

In this paper， using the encrypted sounding observation data of Tazhong observation station in Taklimakan Desert on July 6-17， 2021， the stable boundary layer height was calculated by using Coen method， Rib method， Liu-Liang method and inversion intensity method respectively， and the differences among the calculation results of different methods were compared， and the relationships between near-surface meteorological factors and the height of stable boundary layer is analyzed in combined with 80 m observation tower gradient detection system data. The results show that： （1） During the experiment， the height of stable boundary layer in the hinterland of Taklimakan Desert was less than 1 000 m. The average height calculated by the four methods was 141， 269， 227， 173 m respectively， and the total average height was 202.38 m. The stable boundary layer began to develop after sunset and developed to the thickest around sunrise， and the average height of the stable boundary layer calculated by the four methods increased from 49， 257， 164， 121 m at 22:15 to 220， 290， 242， 188 m at 07:15， respectively. （2） The overall trend of the stable boundary layer height calculated by the four methods is consistent， but there are individual extreme values， and the extreme values are mostly related to special weather phenomena. The height distribution range （10-890 m） of stable boundary layer calculated by Rib method is larger than that calculated by the other three methods， which may be due to the consideration of both thermodynamic and dynamic factors. The heights calculated by the other three methods are slightly lower， probably because the boundary layer development is not uniform at each time， the four-time average at night lowers the overall average and is affected by the intensity of surface radiation cooling and turbulent motion during different observation cases. （3） The stable boundary layer height calculated by the four methods under different weather conditions is also different. Under clear night conditions， the average deviation of the stable boundary layer height calculated by the four methods is the smallest， and the height change trend is similar. In dust weather， the average deviation of the stable boundary layer height calculated by the four methods is in the middle， and the height difference is mainly reflected around sunrise or sunset. In the case of rainy days， affected by the changes of meteorological elements in the boundary layer， the overall height calculated by the four methods is quite different， and the average deviation is also the largest. （4） In sunny days， the stable boundary layer height determined by the Coen method shows a significant increase process， which can fully describe the development and change process of the stable boundary layer at night. There is almost no sudden increase or decrease in the abnormal height value， which is suitable for sunny days with significant thermal effects. Under special weather conditions， the Rib method is recommended. This method considers both the thermal effect and the dynamic effect. It is a comprehensive parameter that covers wind， temperature and humidity at the same time. The calculated boundary layer height has the least uncertainty and is easier to reduce the error. （5） The height of stable boundary layer in the desert hinterland is jointly affected by dynamic and thermal factors， and is significantly correlated with turbulent kinetic energy， wind speed， ground temperature and soil heat flux， with the maximum correlation coefficients of 0.9， 0.88， 0.63 and 0.5.

Key words: stable boundary layer height, calculation method, influence factor, Taklimakan Desert