Spatiotemporal evolution and physical mechanism analysis of boundary layer wind characteristics of typhoon Saola

This study investigated the spatiotemporal evolution of boundary-layer wind characteristics during Typhoon Saola over the Shenzhen and Hong Kong regions and its underlying physical mechanisms. By integrating high-frequency observational data and LiDAR measurements, this study comprehensively analysed wind characteristics, turbulence properties, and backward trajectories of the typhoon. The results show significant regional and vertical differences in wind speed, direction, and vertical wind speed of Typhoon Saola. In Hong Kong, wind fluctuations were notable, with active boundary-layer turbulence and strong high-altitude momentum transport. In contrast, wind characteristics in the Shenzhen region were relatively moderate, with weaker turbulence activity. As the typhoon approached, high-altitude turbulent momentum transport in Shenzhen intensified. However, the overall momentum transport efficiency declined, reflecting a gradual weakening of wind speed during the typhoon. Backward trajectory analysis revealed that airflow in Shenzhen primarily came from land, where friction reduced vertical momentum transport, contributing to the weakening of Typhoon Saola. Moreover, the sparse cloud coverage in Shenzhen contributed to the reduction of typhoon intensity. This study provides new insights into the disturbances and weakening mechanisms of typhoon boundary-layer winds, highlighting how local terrain and airflow path characteristics modulate vertical wind profiles and spatial variability in typhoon-induced wind impacts.