Diagnostic Analysis on Dynamic Factors of the Snowstorm in Northeastern Inner Mongolia during 20-22 April 2020
A diagnostic analysis was performed for the snowstorm process occurred in northeastern part of Inner Mongolia during April 20-22 2020 based on NCEP-GFS data and the dynamical factors,including mass divergence,vertical helicity,mass vertical helicity,moisture vertical helicity,divergence vertical flux,density divergence vertical flux and moisture divergence flux,the generalized potential temperature based thermal vertical helicity,thermal vertical divergence flux.The results showed that:(1)The snowstorm was caused by Northeast Vortex and Northeast Cyclone.Water vapor was transported from the Bohai Sea,the Yellow Sea and the Sea of Japan in the early stage of snowfall,and from the Sea of Okhotsk mainly in the late stage of snowfall.(2)Dynamical factors had good indication significance for the development and evolution of the snowstorm process.(3)The large value area of dynamic factors could cover the heavy snowfall area basically,showing strong signals in the heavy snowfall area and weak signals in the weak snowfall area,which could describe the vertical structure characteristics of the dynamic and thermal fields in snowfall area.(4)By analyzing the characteristics of vertical helicity,moisture vertical helicity,divergence flux,and moisture divergence flux during snowfall process,it was found that the dynamic structure of the middle-lower troposphere over the snowfall area was strengthened after considering water vapor.So the water vapor could highlight the structural characteristics of the dynamic field in the middle and lower troposphere closely related to the snowfall area.The moisture vertical helicity and moisture divergence flux were better indicators for snowfall forecast than other factors.
Northeast of Inner MongoliaSnowstormDynamical factorsDiagnostic Analysis
万方数据
