A Strong Sandstorm Produced by Mongolian Cyclone:A diagnostic analysis

By the use of MICAPS data,FY-2C satellite infrared cloud images and 2.5°×2.5° NCEP reanalysis data,dynamics process and physical fields of a large-scale strong sandstorm on May 25-28,2008 were analyzed.The results showed that the strong sandstorm occurred in dense temperature gradients area before cold advection and dense vorticity gradients area.The warm advection was important thermal factor of the Mongolian cyclone genesis and development during the process of the strong sandstorm,and unstable atmospheric thermal energy and strong winds were the driving forces of the strong sandstorm.The trigger factor for squall line was provided by rapid eastward moving of steps trough at 500 hPa,and convective storm was the main factor triggering the strong sandstorm.Gradients of pressure and temperature before and after the cold front were enlarged by development of the Mongolian cyclone,by which the unstable thermal energy condition was provided for the production of the strong sandstorm.Outbreak sink and southbound of cold advection at 700 hPa provided a powerful driving force for the production of the strong sandstorm.