Journal of the Meteorological Society of Japan. Ser. II
Online ISSN : 2186-9057
Print ISSN : 0026-1165
ISSN-L : 0026-1165
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  • Ying WANG
    2024 Volume 102 Issue 3 Pages 335-352
    Published: 2024
    Released on J-STAGE: April 02, 2024
    Advance online publication: February 08, 2024

    The Meiyu-Baiu front is the main weather system that influences the Yangtze-Huai River area of China in early summer. Convective cells along the Meiyu-Baiu front are very active and often lead to regional flooding disasters. In this study, the multiscale window transform (MWT) and MWT-based multiscale energetics analysis are utilized to investigate the dynamic energy transfers during a typical Meiyu-Baiu rainstorm. It is found that baroclinic instability in the lower stratosphere is possibly a primary trigger for the rainstorm and its diurnal variation. The kinetic energy source for a single rainstorm case varies in its evolution. During shallow convection, the rainstorm itself is a kinetic energy (KE) source. The baroclinic canonical transfer from the rainstorm window brings a lot of available potential energy (APE) to the background flow window, and is further converted into the background flow KE. In contrast, during deep convection, the primary source of KE is the background flow. The barotropic canonical transfer from the background flow contributes to the APE, thus bringing KE into the rainstorm. Implications on Meiyu-Baiu rainstorm forecasting are also discussed.