Comparative Analysis of the Depth Difference Between Two Backflow-Type Blizzards in Inner Mongolia 

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  • 1. Inner Mongolia Institute of Meteorological SciencesHohhot 010051Inner MongoliaChina
    2. Inner Mongolia Autonomous Region Meteorological ObservatoryHohhot 010051Inner MongoliaChina
    3. Chifeng Meteorological Bureau of Inner Mongolia Autonomous RegionChifeng 024000Inner MongoliaChina
    4. Inner Mongolia UniversityHohhot 010021Inner MongoliaChina

Online published: 2025-07-22

Abstract

By using conventional meteorological observationsground densified automatic stationsERA5 0. 25° ×0. 25°hourly reanalysis and global topographic datathe differences between the characteristics and causes in snow depth of two extreme heavy snowfall events under the return flow pattern in southeastern Inner Mongolia on November 18-192020Process 1and November 7-82021Process 2were compared and analyzedwhich can provide the certain references for improving the forecasting ability of heavy snowfall and its impacts in Inner Mongolia. The results show that:(1The two processes occurred in the same seasonwith simi‐ lar areas of heavy snowfall and 24-hour cumulative precipitation. Process 1 had a wider influence rangestronger snow intensity and rare freezing rain weatherwhile Process 2 lasted longer and had deeper snow accumulationwith 11 stations snow depth breaked the historical records.2Both Process 1 and Process 2 were caused under the effect of 500 hPa upper-level troughvortex),700 hPa southwest jet streamand 925 hPa northeast jet stream. Warm and humid air climbed along the cold air mass at the lower levelproducing significant frontogenesisand the combination of the mid-level front area and the low-level northeast reflux results in the extra large snowfall weather.3The intensity of the cold air at the lower level in Process 1 was weakerthe duration was shorterwhile the intensity and thickness of the southwest airflow at the mid-level were strongerresulting in a warmer and more humid mid-level atmosphere and deeper warm layer. The content of liquid water in the clouds at the mid and lower levels was significantly higher than that in Process 2which conducived to the establishment of a melting layer. Snowflakes or ice crystals melt in the melting layer. In the early stageit is freezing rainand in the later stageit falls to the ground in the form of wet snow. In Process 2affected by the cold vortexthe system configuration was deeperthe lower-level atmosphere was relatively colderthe cold air mass was stronger and more persistentwhich has no melting layer. The temperature conditions are suitable for the formation of flaky snowflakes in the air. After landingit is mainly dry snowwhich is more conducive to the formation of a larger snow depth.4At the initial stage of the snowfallthe near-surface temperature in Process 1 was above -1 ℃and the surface temperature was around 0 ℃. Wet snow could not quickly freeze when it fell to the groundand it was easy to form freezing rain with the near-surface temperature decreased. In Process 2the nearsurface temperature was -9 ℃ and the surface temperature was -3 ℃. The near-surface wind speed was weakerwhich was conducive to the formation of snow accumulation when relatively dry large snowflakes fell to the ground.

Cite this article

LIN Hongjie, HUANG Xiaolu, MENG Fanfu, LI Ruiqing . Comparative Analysis of the Depth Difference Between Two Backflow-Type Blizzards in Inner Mongolia [J]. Plateau Meteorology, 0 : 1 . DOI: 10.7522/j.issn.1000-0534.2025

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