On November 26, Yantai, Shandong, China experienced the first "cold flow snow" of this winter. The "cold flow snow" observation experiment team of eastern China promptly carried out analysis and discovered that the ice crystal formation height of this process was low, the shallow convection active, and the growth efficiency of snow particles in the air high. Snowflake samples obtained at the site are being further analyzed to provide first-hand data for exploring the reason of the disaster-causing snowstorm in winter.

On November 19, the "cold flow snow" observation experiment (hereinafter referred to as the Experiment) in East China was launched in Yantai. The Experiment focused on the formation mechanism and influence of the "cold flow snow", and harnessed the integrated observation methods of atmospheric physics and atmospheric chemistry to study the multi-scale mechanism of disaster-causing cold flow snowstorm.

The "cold flow snow" often occurs in the coastal areas of China's Huanghai Sea and Bohai Sea,but also coastal areas of regions like Jiangsu, Shanghai, and Liaoning, and most typical in Yantai and Weihai. According to statistics, the "cold flow snow" accounted for more than 80% of the total number of snow days.

Different from the regular snowfall, the convection and locality of the "cold flow snow" are quite conspicuous. In December 2023, there were several "cold flow snow" processeson the Shandong Peninsula, among which the snow depth in Wendeng, Weihai registered 74 cm, shattering the record of the heaviest snow depth in Shandong.

During the Experiment Photoed by ZHENG Hepeng

Through the integratedobservation of aerosol, cloud and snowfall, the Experiment can gain an insight into the mechanism of human-induced and dust aerosol transport on ice precipitation, clarify the multi-scale mechanism of the disaster-causingblizzard in east China in winter, and ramp up the forecasting ability of winter precipitation.

The Experiment will last 5 month and form integrated detection system on the strength of FENGYUN meteorological satellites, aerosol radiation observation network in Shandong Peninsula, automatic weather stations, and S band dual polarization weather radar network and coastal buoy observation network, which is capable of conducting full-chain observation of the mesoscale, storm-scale and particle-scale of the "cold flow snow".

During the Experiment, a raft of newly developed domestic sophisticated cloud precipitation detection instruments were put into use to achieve refined observation from "cold flow snow" storms to single snow crystals. These instruments also conducted remote sensing and in-situ observations of the characteristics of snowflake spectrum distribution, density, species, concentration and shape.

The Experiment was hosted by the Chinese Academy of Meteorological Sciences (CAMS), National University of Defense Technology (NUDT), Shandong Provincial Meteorological Service. Besides, 20 institutions like Peking University, Institute of Atmospheric Physics of the Chinese Academy of Sciences, the China Meteorological Administration Meteorological Observation Centre (CMA MOC), Beijing Municipal Weather Modification Centre have participated.

Editor: LIU Shuqiao