Analysis on Characteristic Variations of Physical Quantities in the Near Surface Layer during a Severe Haze Process in Yueyang Hunan Province

Using 3D ultrasound anemometer data and aerosol data, several conclusions have been reached based on the analysis of wind field and turbulence variation characteristics in the near surface layer in Yueyang during a severe haze process on 28 January 2017. Major conclusions are as follows. (1) The horizontal wind speed, vertical wind speed, and wind shear all are zero at about 130 minutes ahead of the occurrence of the heavy pollution process (at 0150 LST 28 January), and the atmosphere remained in stable condition. (2) The turbulent intensity (I_v) exhibited an abnormal signal before the starting and ending of the heavy pollution. The abnormal value of I_v was 4.15 at 130 minutes ahead of the beginning of the heavy pollution and the value was 3.24 at 180 minutes ahead of the ending of the heavy pollution (at 0900 LST 28 January). (3) The turbulent kinetic energy and momentum flux decreased to 0.0 m²/s² at 130 minutes ahead of the occurrence of the heavy pollution. There is a good agreement between the occurrence time of the anomalous signals of turbulence and average physical quantities. This paper is focused on the analysis of abnormal characteristics of boundary layer turbulence during the formation, development and dissipation of the severe haze. The abnormal signals of the occurrence and dissipation of the severe haze are detected through the above analysis. The aim of this paper is to get a better understanding of severe haze weather and provide scientific basis for its prediction.