Impact of Boundary Layer Jets on Cold Pool Characteristics Observed From the 356-m High Shenzhen Meteorological Tower

Abstract

The interaction between cold pools and low-level vertical wind shear plays an important role in the initiation and development of convection. However, the impact of the boundary layer jets (BLJs), with their unique low-level vertical wind shear structures and moisture transport properties, on cold pools remains incompletely understood. This study utilizes observations from the 356-m high Shenzhen Meteorological Tower to compare cold pool characteristics under BLJ and non-BLJ conditions during April to June from 2018 to 2020. A total of 54 cold pools are identified, with 26 influenced by BLJs. BLJ-related cold pools typically exhibit weaker average temperature drops, more pronounced decreases in specific humidity, and higher turbulence transport compared to those unrelated to BLJs. The enhanced moisture transport by BLJs constrains rainfall evaporation, resulting in weaker cold pools. In addition, the strong wind shear associated with BLJs promotes upward energy transport and turbulence, further weakening the intensity of cold pool. These distinctions are particularly pronounced in cold pools associated with mesoscale convective systems rather than individual convective cells. These findings provide valuable insights into the complex interactions among cold pools, BLJs, and convection in South China.