Classification of Turbulent Mixing Driven Sources in Marine Atmospheric Boundary Layer With Use of Shipborne Coherent Doppler Lidar Observations

A method to identify the turbulent mixing sources within the marine atmospheric boundary layer (MABL) based on the shipborne coherent Doppler lidar measurements is introduced in this paper. Combining with the coherent Doppler lidar signal-to-noise ratio, vertical velocity skewness, turbulence kinetic energy dissipation rate, and wind shear intensity, the categories of turbulent mixing sources and the specific turbulent mixing sources could be determined. The method is applied into two voyages of MABL observation during May 2021 in the South China Sea and during April 2022 in the Bohai Sea and Yellow Sea. The turbulent mixing processes are captured and the classification of the turbulence driven sources within the MABL are realized. The temporal-spatial evolution characteristics of the turbulence mixing process in the MABL are investigated under different weather conditions containing clear-sky day, cloudy-sky day, and sea-fog day. The convective mixing process is recognized in the daytime of the clear-sky day and the intermittent cloud-driven turbulence exists below the cloud layer. Additionally, the turbulent mixing is weak which could not act as the main driven source during the sea-fog day. Furthermore, the dominant turbulence scale analyses of different turbulence sources are conducted based on the cospectra of the vertical velocity and the horizontal speed measurements. The turbulence parameters of different turbulence sources are statistical analyzed and compared in different sea areas. The classification method has the broad application prospects on the study of the air-sea interaction.

Automated summary

This paper introduces a method to identify turbulent mixing sources within the marine atmospheric boundary layer (MABL) using shipborne coherent Doppler lidar measurements. The method is applied to observations in the South China Sea and the Bohai Sea and Yellow Sea, revealing differences in the temporal-spatial evolution characteristics of turbulent mixing processes under different weather conditions. The convective mixing process is identified in clear-sky days, while turbulent mixing is weak during sea-fog days.