Elucidating the Mesoscale Convective Clouds in East Asia Using Both Geostationary Satellite and Weather Radar Measurements

The spatial and temporal pattern of mesoscale convective system (MCS) remains one of the least well-observed parts of convection in East Asia, partly due to limited satellite data. We here developed an improved algorithm by virtue of combining the area overlapping (AOL) with the Kalman Filter (KF), which captures much smaller MCSs that are unavailable otherwise. Several influential factors like the overlapping rate and splitting/merging in the AOL method, and the initial state variable in the KF method, are adequately taken into account. The occurrence frequency, and moving trajectory of two types of MCS, including the ordinary MCS and superconvective system (SCS), have been comprehensively examined in East Asia for the warm season (April to September) of 2016. Comparing satellite-derived MCS with ground precipitation and radar measurements indicates good performance of our algorithm. In particular, the moving direction of MCS strongly depends on latitudes, so does the horizontal velocity. Compared with over ocean, the frequency of MCSs dominate over land or along coasts in the tropics, where strong moisture flux convergence is frequently observed in the low troposphere. In addition, the MCSs detected in eastern China can roughly capture the meridional propagation over time, which corresponds well to the precipitation belts linked to Meiyu front systems. The SCSs dominate over the Bay of Bengal and South China Sea due to the large-scale circulation. Furthermore, the life cycle of MCS will be explicitly analyzed with the aid of ground-based weather radar measurements in North China Plain. Our findings advance our understanding of the MCSs during warm season over East Asia.