Abstracts for the 5th International GAME Conf.

3-5 October 2001

Aichi Trade Center

Nagoya Japan

Generation Mechanism of Precipitation and Vorticity in the Meiyu Front during GAME/HUBEX 1998 IOP

Takeshi Maesaka (1), Hiroshi Uyeda (2), Teruyuki Kato (3), Masanori Yoshizaki (3)

We analyze generations of precipitation and vorticity in the Meiyu front using Doppler radar data during the GAME/HUBEX (Huaihe River Basin Experiment) 1998 IOP. We also analyze the frontal structure which contributes to the generation of precipitation and vortex by using Meteorological Research Institute - Nonhydrostatic Mesoscale Model (MRI-NHM). Estimating the generation rate of precipitation water in a line shaped precipitation system on 29 June (cold front type), most precipitation is generated below 2 km height. This layer corresponds the peek of the apparent moisture sink calculated by sounding data network. Numerical simulation with MRI-NHM shows that the line shaped precipitation system is embedded in the wide stratiform region around the Meiyu front. But the air with low equivalent potential temperature exists in 2 - 5 km height and intensify low level convective instability. It means that low level atmosphere is very moist enough to trigger the condensation and to cause heavy rain by little lifting. In the IOP, some meso-gamma vortex with strong convection are observed by Doppler radar. Estimating the tendencies of vertical vorticity about the typical vortex on 2 July by using dual Doppler radar analysis, the stretching effect mainly contribute to intensify the meso-gamma vortex. The vorticity generation of the Meiyu frontal scale is also investigated by using MRI-NHM experiment. From this investigation, tilting effect mainly intensifies the low level vorticity (below 2 km height) in the frontal scale. These analyses revels that meso-gamma vortex is intensified by the stretching process and initial vorticity is mainly generated by tilting process in the Meiyu frontal zone. As a result of the analyses of the generation on precipitation and vorticity, convective instability and vorticity generation below 2 km height are important for making heavy precipitation in the Meiyu front.

Submittal Information

Name : Date :
    Takeshi Maesaka
    30-May-01-16:49:55
Organization : Theme :
    Hokkaido University
    Theme 2
Address : Presentation :
    Hydrospheric Atmospheric Research Center, Nagoya University, Furo-cho, Chikusa, Nagoya.
    Poster or oral
Country : Abstract ID :
    JAPAN
    T2TM30May01164955
Phone : Fax :
    +81-52-789-3494
E-mail :
    maesaka@ihas.nagoya-u.ac.jp