Page 139 - 《高原气象》2026年第1期

1 期 林弘杰等：内蒙古两次回流型特大暴雪积雪深度差异对比分析 135

Comparative Analysis of the Depth Difference Between Two

Backflow-Type Blizzards in Inner Mongolia

1
LIN Hongjie ， HUANG Xiaolu ， MENG Fanfu ， LI Ruiqing 4
3
2
（1. Inner Mongolia Institute of Meteorological Sciences， Hohhot 010051， Inner Mongolia， China；
2. Inner Mongolia Autonomous Region Meteorological Observatory， Hohhot 010051， Inner Mongolia， China；
3. Chifeng Meteorological Bureau of Inner Mongolia Autonomous Region， Chifeng 024000， Inner Mongolia， China；
4. Inner Mongolia University， Hohhot 010021， Inner Mongolia， China）

Abstract： By using conventional meteorological observations， ground densified automatic stations， ERA5
（0. 25°×0. 25°） hourly reanalysis and global topographic data， the 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 -19， 2020 （Process 1） and November 7 -8， 2021 （Process 2） were compared and
analyzed， which can provide the certain references for improving the forecasting ability of heavy snowfall and its
impacts in Inner Mongolia. The results show that： （1） The two processes occurred in the same season， with simi‐
lar areas of heavy snowfall and 24-hour cumulative precipitation. Process 1 had a wider influence range， stronger
snow intensity and rare freezing rain weather， while Process 2 lasted longer and had deeper snow accumulation，
with 11 stations snow depth breaked the historical records.（2） Both Process 1 and Process 2 were caused under
the effect of 500 hPa upper-level trough （vortex）， 700 hPa southwest jet stream， and 925 hPa northeast jet
stream. Warm and humid air climbed along the cold air mass at the lower level， producing significant frontogene‐
sis， and the combination of the mid-level front area and the low-level northeast reflux results in the extra large
snowfall weather.（3） The intensity of the cold air at the lower level in Process 1 was weaker， the duration was
shorter， while the intensity and thickness of the southwest airflow at the mid-level were stronger， resulting 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 2， which conducived to the establish‐
ment of a melting layer. Snowflakes or ice crystals melt in the melting layer. In the early stage， it is freezing rain，
and in the later stage， it falls to the ground in the form of wet snow. In Process 2， affected by the cold vortex，
the system configuration was deeper， the lower-level atmosphere was relatively colder， the cold air mass was
stronger and more persistent， which has no melting layer. The temperature conditions are suitable for the forma‐
tion of flaky snowflakes in the air. After landing， it is mainly dry snow， which is more conducive to the forma‐
tion of a larger snow depth.（4） At the initial stage of the snowfall， the 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
ground， and it was easy to form freezing rain with the near-surface temperature decreased. In Process 2， the near-
surface temperature was -9 ℃ and the surface temperature was -3 ℃. The near-surface wind speed was weaker，
which was conducive to the formation of snow accumulation when relatively dry large snowflakes fell to the
ground.
Key words： backflow blizzard； snow depth； freezing rain； dry snow； comparative analysis