UC Santa Barbara

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 fromthe 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-ß circular convective systems (MßCCSs), meso-ß elongated convective system (MßECSs), and two additional types named small meso-ß circular convective systems (SMßCCSs) and small meso-ß elongated convective systems (SMßECSs). 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 208, 308, and 508N. The frequency of MCSs occurrences is maximized at the zonal band around 208N 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. Mean while, fromMay 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, MßCCSs, and MßECSs) 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.