Mesoscale Convective Systems in the Asian Monsoon Region From Advanced Himawari Imager: Algorithms and Preliminary Results

Abstract

The knowledge of mesoscale convective system (MCS) in the Asian monsoon region remains still deficient due to the limited available data and less powerful algorithms. Here, using the data from Advanced Himawari Imager onboard Himawari‐8 (HW8), an improved algorithm combining the area overlapping with the Kalman filter is developed, which captures much smaller MCSs that are unavailable otherwise. Several influential factors like the overlapping rate and splitting/merging in the area overlapping method, and the initial state variable in the Kalman filter method, all of which were less appreciated, are handled explicitly. The occurrence frequency, and moving trajectory of two types of MCS, including the ordinary MCS and superconvective system, has been comprehensively examined in the Asian monsoon region for the warm season (April to September) of 2016. Comparison analyses with ground precipitation and radar measurements confirm the 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 dominates 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 superconvective systems dominate over the Bay of Bengal and South China Sea due to the large‐scale circulation. Our findings provide new insights to spatiotemporal patterns of MCSs during warm season in the Asian monsoon region.

Mesoscale Convective System Precipitation Characteristics over East Asia. Part I: Regional Differences and Seasonal Variations

“…A comprehensive study of zonal distributions and life cycles of MCSs over China with a special focus on the classification of MCSs into different morphologies (e.g., quasi-circular MCSs and elongated MCSs), has been conducted based on brightness temperature data from the geostationary satellite Fengyun 2 (Yang et al 2015). Chen et al (2019) have shown the preliminary results of MCS major features (including horizontal movement and frequency of occurrence) in the whole of East Asia, by investigating a 1-yrlong dataset from Advanced Himawari Imager onboard Himawari-8. Other studies have also documented organizational modes (Zheng et al 2013), life cycle characteristics (Ai et al 2016), formation mechanisms (Fu et al 2017) of MCSs, and the associated atmospheric circulation patterns (He et al 2017) over the plain region of central-eastern China.…”

“…MCSs can be identified and tracked by multiple atmospheric fields, including but not limited to cloud-related variables such as cloud-top brightness temperature derived from satellite infrared images (Yang et al 2015;Chen et al 2019;Q. Yang et al 2019), midtropospheric vorticity (Wang et al 2011), Doppler radar composite reflectivity (Zheng et al 2013), and surface precipitation (Houze 2004Clark et al 2014;Prein et al 2017a,b).…”

Linkage Between the Vertical Evolution of Clouds and Droplet Growth Modes as Seen From FY‐4A AGRI and GPM DPR

“…In contrast, passive sensor can only measure information on the cloud surface (Chen et al, 2019). Even if the vertical evolution of R e can be obtained through appropriate assumptions, the structure at low level is still unknown.…”

East Asian Study of Tropospheric Aerosols and their Impact on Regional Clouds, Precipitation, and Climate (EAST‐AIRCPC)

“…The advent of new‐generation geostationary meteorological satellite makes it possible to identify the life cycle of clouds in Asian monsoon regions (Chen et al, ). This may lead to a major leap in our understanding of the aerosol impact on cloud lifetimes, which is the least understood aerosol‐cloud‐interaction process.…”