A low-temperature, freezing rain and snow event occurred in Guizhou from the nocturnal of 21 January to 5 February in 2018. This event can be divided into three stages, namely, freezing rain-predominated period in central and eastern Guizhou, light rain and snow period in central and western Guizhou, and snowfall-developing period in central and western Guizhou. Using datasets of conventional observations and NCEP FNL reanalysis grid data with 1°×1° resolution, we have conducted a causality analysis on the low-temperature, freezing rain and snow during the three stages of this event, and established three sounding models for freezing rain, weak rain and snow, and snow based on statistics of the observations. The main results are as follow. (1) In the three stages, there are different circulation patterns in the middle-high latitudes, i.e., emerging the Ural blocking high, the meridianal revising of the zonal trough and the two troughs and one ridge pattern, respectively. (2) The influence of four strong cold air processes and the westward movement of the stationary front are the important reasons that low-temperature, freezing rain and snow weather happened from east to west of Guizhou. (3) The precipitation phase is in coherence with the different temperature and humidity characteristics of being warm and humid before and cold and humid after this event, and the efficient precipitation promotes the rapid growth of ice before 29 January 2018. (4) Sounding models in the three stages show that all the different phased precipitation is caused by frontal precipitation occurred in the side of the cold air mass behind the stationary front. Many factors, such as temperature stratification, the height of the wet layer, the inversion gradient, the temperature of the cloud top, the temperature at the inversion bottom and the ground temperature, have important influence on the formation of different precipitation phases.
DU Xiao-Ling, et al
.2018. Tentative analysis on the cause of a low-temperature, freezing rain and snow event in Guizhou between the end of January and the beginning of February in 2018[J].
Torrential Rain and Disasters, 37(5): 410-420.