Assigned Session: FS 3.216: High-Resolution Modeling of the Atmosphere
Observed and simulated trapped lee waves over Hengduan Mountains
Abstract ID: 3.5291 | Pending | Talk/Oral | TBA | TBA
Haile Xue (0)
Haile Xue ((0) Haile Xue, 北京市海淀区中关村南大街46号,中国气象局地球系统数值预报中心, 100081, 北京, 北京, CN)
(0) Haile Xue, 北京市海淀区中关村南大街46号,中国气象局地球系统数值预报中心, 100081, 北京, 北京, CN
Due to the lack of high temporal and spatial resolution observations, the diurnal variation of the trapped lee wave (TLW) remains unknown. We employed the U-Net deep learning model to identify more than 3.5 thousand images with TLWs from over thirty thousand 500-m resolution Fengyun-4 satellite images with a 15-minute interval during the winter times from 2019 to 2023. Results shows that the wavelength is peaked at the late afternoon with high low-level winds and low atmospheric stability while the amplitude and propagating area are peaked at relative earlier afternoon with a most turbulent boundary in a day. The TLWs were further investigated in realistic and idealized large-eddy simulations by using WRF and ICON models, respectively. It is found that the effects of the stagnant and stable layer near the surface plays a wave-absorbing role in the nonlinear regime as in linear theories or simulations while the wave lengthening is largely related to the wind speed over the mountain.
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