Characteristics of Mesoscale Convective Systems over China and Its Vicinity Using Geostationary Satellite FY2

This study investigates mesoscale convective systems (MCSs) over China and its vicinity during the boreal warm season (May-August) from 2005 to 2012 based on data from the geostationary satellite Fengyun 2 (FY2) series. The authors classified and analyzed the quasi-circular and elongated MCSs on both large and small scales, including mesoscale convective complexes (MCCs), persistent elongated convective systems (PECSs), meso-beta circular convective systems (M beta CCSs), meso-beta elongated convective system (M beta ECSs), and two additional types named small meso-beta circular convective systems (SM beta CCSs) and small meso-beta elongated convective systems (SM beta ECSs). Results show that nearly 80% of the 8696 MCSs identified in this study fall into the elongated categories. Overall, MCSs occur mainly at three zonal bands with average latitudes around 20 degrees, 30 degrees, and 50 degrees N. The frequency of MCSs occurrences is maximized at the zonal band around 20 degrees N and decreases with increase in latitude. During the eight warm seasons, the period of peak systems occurrences is in July, followed decreasingly by June, August, and May. Meanwhile, from May to August three kinds of monthly variations are observed, which are clear northward migration, rapid increase, and persistent high frequency of MCS occurrences. Compared to MCSs in the United States, the four types of MCSs (MCCs, PECSs, M beta CCSs, and M beta ECSs) are relatively smaller both in size and eccentricity but exhibit nearly equal life spans. Moreover, MCSs in both countries share similar positive correlations between their duration and maximum extent. Additionally, the diurnal cycles of MCSs in both countries are similar (local time) regarding the three stages of initiation, maturation, and termination.