Study on wavy distribution of rainfall associated with typhoon Matsa （2005）

An analysis is made to investigate the structure features of the extensive heavy rainfall left by typhoon Matsa, after its landfall in mainland China in August 2005, based on a range of observational results, including surface intensive observation data, TBB data from China's FY-2 satellite, and NCEP 1°×1° reanalysis data. The study tries to explore the interaction between atmospheric waves, 3-D atmospheric structures, and typhoon rainbands. Observational facts, diagnostic analysis, and atmospheric wave theory are used to look into the formation mechanism of distant typhoon rainbands. Results show that (1) Matsa rainbands have the features of noticeable wave train distribution and long distance propaga-tion; (2) the typhoon rainbands extend as far as 2000 km northwardly from the typhoon center, with a wavelength of 500―1000 km and a wave period of 12―24 h; (3) the wave structure of Matsa rainbands is closely associated with the corresponding wave variation of the ambient 3-D atmospheric structures, including disturbance vorticity, divergence field, vertical motion field, water vapor flux divergence field, etc. (4) both observational facts and theoretical analysis show that the northward extending typhoon rainbands are associated with the mixed effects of atmospheric inertia wave and internal gravity wave; (5) only under proper atmospheric stratification and vertical wavenumber of gravity wave, can a ty-phoon stimulate such a wave being able to reach such a distance, and result in extending wavy rain-bands.

Study on wavy distribution of rainfall associated with typhoon Matsa (2005)

An analysis is made to investigate the structure features of the extensive heavy rainfall left by typhoon Matsa, after its landfall in mainland China in August 2005, based on a range of observational results, including surface intensive observation data, TBB data from China’s FY-2 satellite, and NCEP 1°×1° reanalysis data. The study tries to explore the interaction between atmospheric waves, 3-D atmospheric structures, and typhoon rainbands. Observational facts, diagnostic analysis, and atmospheric wave theory are used to look into the formation mechanism of distant typhoon rainbands. Results show that (1) Matsa rainbands have the features of noticeable wave train distribution and long distance propagation; (2) the typhoon rainbands extend as far as 2000 km northwardly from the typhoon center, with a wavelength of 500–1000 km and a wave period of 12–24 h; (3) the wave structure of Matsa rainbands is closely associated with the corresponding wave variation of the ambient 3-D atmospheric structures, including disturbance vorticity, divergence field, vertical motion field, water vapor flux divergence field, etc. (4) both observational facts and theoretical analysis show that the northward extending typhoon rainbands are associated with the mixed effects of atmospheric inertia wave and internal gravity wave; (5) only under proper atmospheric stratification and vertical wavenumber of gravity wave, can a typhoon stimulate such a wave being able to reach such a distance, and result in extending wavy rainbands. Supported by the National Grand Fundamental Research 973 Program of China (Grant No. 2004CB418301) and the National Natural Science Foundation of China (Grant Nos. 40675033, 40575018 and 40505009)