An Analysis on Sand Storm Weather Characteristic in Northern China

Based on the NCEP/NCAR 6 hours Reanalyzed data,we analyzed the synoptic causes of the sandstorm weathers occurred in March 18-22,2002.By analysis of atmospheric circulation,diagnosis of physical quantity,study of the upper-level jet stream,the results indicated that the Mongolian cyclone is a major effect system of the sandstorm weather,the occurrence and the development of cyclone commenced in baroclinicity region,the main contribution to the intensification of cyclone came from the thermal advection,it is must not be overlook the function of the atmospheric baroclinicity.This sandstorm weather case was mainly caused by cyclone cold front and the surface high wind behind the cold front.The formation of the surface strong wind is caused by the cyclogenesis,clod advection behind the cold front and the downwardly transmission of the upper-level jet momentum.