Abstract:Using the data of lighting locator, densely-obtained automatic station data and conventional data, 35 “thundersnow” events that occurred in Shandong Province from 2006 to 2015 are analyzed. The “thundersnow” can be divided into warm advection type and marine effect type according to the formation mechanism, and the characteristics in related element fields and physical quantity fields for the two kinds of events are summarized in detail. The main conclusions are as follows. Within 24 h before warm advection “thunderstorm” events, the temperature in the middle and lower troposphere is warming up, and the closer it is to the ground, the more obvious the temperature rise is. The events tend to occur when there is a sudden invasion of strong cold air from 850 hPa to the ground, the temperature difference between the upper and lower layers can reach 10 ℃, and the circulation situation is adjusted from uniform southward airflow to cold cushion in lower layer and the warm advection in the mid-upper layers. The center of ascending motion and the unstable stratification appear in the mid-upper layers. Two days before the marine effect “thunderstorm” events, the Bohai Sea is controlled by warm ridges, and the sea surface temperature is about 2 ℃ higher than usual. When the northward current behind the upper trough suddenly increases and sweeps across the Bohai Sea, the “thundersnow” events occur. Although convective activity also occurs in the lower troposphere, the thickness of unstable stratification and the temperature difference between upper and lower layers are larger than that in marine effect snowstorm in general.