Lu Zhang1, Hongsheng Zhang1*, Qianhui Li1, Wei Wei2, 3, Xuhui Cai4, Yu Song4, Ali Mamtimin5, 6*, Minzhong Wang5, 6, Fan Yang5, 6, Yu Wang5, 6, Chenglong Zhou5, 6
1 Laboratory for Climate and Ocean-Atmosphere Studies, Department of Atmospheric and Oceanic Sciences, School of Physics, Peking University, Beijing 100871, P.R. China.
2 CMA Earth System Modeling and Prediction Centre, Beijing 100871, P.R. China.
3 State Key Laboratory of Severe Weather, Chinese Academy of Meteorological Sciences, Beijing 100081, P.R. China.
4 State Key Joint Laboratory of Environmental Simulation and Pollution Control, College of Environmental Science and Engineering, Peking University, Beijing 100871, P.R. China.
5 Taklimakan Desert Meteorology Field Experiment Station of CMA, Institute of Desert Meteorology, China Meteorological Administration, Urumqi 830002, P.R. China.
6 National Observation and Research Station of Desert Meteorology, Taklimakan Desert of Xinjiang / Xinjiang Key Laboratory of Desert Meteorology and Sandstorm, Urumqi 830002, P.R. China.
Corresponding authors: Hongsheng Zhang (hsdq@pku.edu.cn), Ali Mamtimin (ali@idm.cn)
Abstract
The deep convective boundary layer (CBL) in the Taklimakan Desert plays an important role in the climate system in East Asia. Based on the observation experiment and large-eddy simulation, turbulent mechanisms for its formation were revealed in this study. This explained why the daily maximum CBL depth was independent of surface heating. In the late-morning, there was a weak temperature inversion and a near-neutral residual layer (RL) above the CBL. With the development of the CBL, stronger convection could penetrate the RL and even overshoot the top of the RL. The distinctive boundary-layer process entrained free-tropospheric air to warm the RL and then promoted the entrainment of the warmed air in the RL into the CBL. This extra energy supply effectively contributed to the growth of the CBL. With further positive feedback between the CBL and RL depths, a deeper CBL would form in consecutive fair-weather conditions.
Key Points
· The convective boundary layer (CBL) in the Taklimakan Desert commonly developed to 3,000 m and even reached over 5,000 m in summer
· Strongly penetrative convection could overshoot the top of near-neutral residual layer (RL) and entrain free-tropospheric air into the RL
· The warmed RL strengthened the entrainment heating, which supplied extra energy for the further development of deep CBL
Citation
Zhang, L., Zhang, H., Li, Q., Wei, W.,Cai, X., Song, Y., et al. (2022). Turbulent mechanisms for the deep convective boundary layer in the Taklimakan Desert. Geophysical Research Letters, 49, e2022GL099447. https://doi.org/10.1029/2022GL099447
