Analysis of the back-bent warm front structure associated with an explosive extratropical cyclone over land

The back-hent warm front of extratropical cyclone was a significant achievement as done in the field experiment on rapidly intensifying cyclones over the Atlantic Occan(ERICA) in the late 1980s because it modified the occluded front concept in the classical Norwegian cyclone model. This evolution process was found in cyclonic cloud systems over the Eurasian continent as observed from geosynchronous satellite images. Therefore,the frontal structure and feature of the Mongolian cyclone that occurred on 11-14 May 2012 was analyzed using conventional ohservations,the NCEP 10 x 10 reanalysis data and water vapor images from FY-2E. It is shown that the back-hent warm front and warm seclusion existed in the extratropical cyclone over land,but its warm core,which extended up to the 600 hPa level, was weaker than that of the marine cyclone. In addition a dry center at the 850 hPa level was found near the warm core and it partly coincided with the low center. It is also found that the moist air ascended near the back-bent warm front zone while the dry air descended within the warm,dry center. And the potential temperature gradient in the back-bent warm front was stronger than that in the cold front in the boundary layer. In the dry conveyor belt,the front zone located evidently in the middle-upper troposphere with low relativity humidity and slowly up-ward vertical velocity in general. The driest air was situated above the front zone with the warm air descending.