The Analysis of the Satellite Cloud Images and Radar Echo Characteristics of Two Excessive Snowstorms in TongLiao
The characteristics of satellite water vapor images and radar echoes of the excessive snowstorm processes during November 17 to 19,2020 and November 6 to 10,2021 in Tongliao were analyzed and compared,based on conventional observation data and ERA5(0.25˚×0.25˚)reanalysis data.The results showed that the favorable circulation patterns for both excessive snowstorms included the intense development of high-altitude cold vortex(low trough)and cyclone,and the close-range transport of abundant water vapor by low-level jet.The satellite cloud images of two excessive snowstorms showed a transition from baroclinic leaf cloud system to comma cloud system,and finally to spiral cloud system,with distinct T-shaped structures and back-bent warm fronts.The initial stage of snowfall was characterized by return flow snowfall,while the later stage was dominated by cold conveyor belt.The evolution stages of the satellite cloud images corresponded well to the beginning,strengthening,and weakening of snowfall.In the intense development stage of the high-altitude cold vortex(low trough),vortex cloud systems were observed in the southeast,northeast,and northwest of the cold vortex,corresponding to the strongest snowfall stage.The spiral cloud belt in the second snowstorm process was more obvious than that in the first snowstorm process,and the snowfall duration was also longer.The radar echoes of two excessive snowstorm processes were uniformly distributed flaky stratiform cloud precipitation echoes,with a good correlation between echo intensity and snowfall intensity.The first snowstorm process featured a typical zero-layer bright band,an inversion layer and a melting layer,which provided good indicators of precipitation phase.The echo movement of the second snowstorm process was consistent with wind field rotation,which showed a cyclonic rotation,while the evolution of the echoes were in line with the intense development and rotation of the cold vortex as it moved eastwards and northwards.
Excessive snowstormCharacteristics of water vapor cloud imagesRadar echoes characteristics
万方数据
维普
