(1) Graduate school of Science, Hokkaido University
(2) HyARC, Nagoya University
(3) Meteorological Research Institute
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.