Explosive extratropical cyclone, referred to as "meteorological bomb", is a family of rapidly-developing cyclonic weather systems. Sander and Gyahum (1980) defined explosive cyclogenesis as a reduction of central sea level pressure of a cyclone at a rate of 24 hPa within 24-hour (1 Bergeron) or greater. These rapidly-developed cyclones may exert terrible threats to the safety of maritime navigation over oceans, and have become one of serious topics in marine meteorology. Thus, it is of great importance to investigate these dangerous weather systems. Previous studies indicated that the Northwestern Pacific was the area where explosive extratropical cyclones occurred frequently. Figure 1 presents 4 explosive cyclones occurred over the Northwestern Pacific from 2010 to 2013, respectively. These cyclones most formed initially in the mainland of China, and moved northeastward during their developments. After entering into the Yellow Sea, they underwent rapid developments, and almost the whole Northeastern Pacific, seeing from the weather charts, was occupied by these giant cyclones. In our recent study, we investigated 368 explosive cyclone cases in the area (20oN-60oN, 110oE-180oE) within recent 10-year (2004-2013) during the season from October to April of next year by using FNL (Final Analysis) data. For these explosive cyclones, their moving tracks, annual number of explosive cyclones, monthly number of explosive cyclones, distribution of initial explosive locations, distribution of maximum deepening rate locations, distribution of minimum central pressure locations, and the maximum deepening rates were documented. Additionally, we will present an explosive cyclone which occurred from 3 to 5 March 2007, by using all available observational data, satellite imagery, high-resolution WRF modeling data to document its evolutionary process, temporal-spatial structure and developing mechanism.
Explosive Extratropical Cyclones over the Northwestern Pacific within Recent 10-Year from 2004 to 2013