Causes of Strong Sandstorm Weather on March 15, 2021 in Ulanqab City.

The severe sandstorm process in Ulanqab, Inner Mongolia on March 15, 2021 was analyzed and discussed from the aspects of weather facts, weather causes and dynamic diagnosis. The results show that the strong cold air in West Siberia rapidly moved eastward, and the surface cold front moved eastward to Ulanqab with significant warming in the previous period, resulting in gale and sandstorm weather. This severe sandstorm process occurred in basically stable atmospheric stratification. During the strong sandstorm and extremely strong sandstorm process on March 15, the strong warming in the early period near the surface led to the surface thermal instability, and sand was generated by the upward movement of the Mongolian cyclone. Over the upper northwest air stream, barocline disturbance developed unsteadily, and the upper cold advection stimulated the secondary circulation of front perpendicular to the surface; the surface cyclone turned into strong cold front, and then strong sandstorm weather occurred in Ulanqab. [ABSTRACT FROM AUTHOR]