Abstracts for the 5th International GAME Conf.
3-5 October 2001
Aichi Trade Center
Nagoya Japan
On the initiation of meso--lows on the Meiyu front in China (Case studies for the Meiyu in 1991 and 1998)
Kuranoshin Kato (1), Naoto Kio (1), Takahiko Taniguchi (1), Biao Geng (4), Jun Matsumoto (5)
(1) Faculty of Education, Okayama University
(4) Frontier Observational Research System for Global Change
(5) Graduate School of Sciences, the University of Tokyo
Initiation processes of the meso--lows on the Meiyu front were
examined for cases around 29 `30 June 1998 and 2 ~ 3 July 1991. The
former case is in IOP of the GAME/HUBEX, and the latter one is in the
period when the extreme floods occurred in the Huaihe River Basin.
Meso--scale lows sometimes appear on the Meiyu/Baiu front and play
important roles in the multi-scale interaction processes between the
large-scale and the meso-- and -scale convective systems. It is
known that the Tibetan Plateau plays an important role in initiating the
meso--scale lows. That is, the so-called the southwest vortices are
often originated around the eastern foot of the Plateau and move
eastward on the Meiyu front. In the present cases, however, the
rainfall on the Meiyu front was firstly enhanced with organization of
the convective clouds into a meso--scale cloud cluster. The
initiation of the meso--lows followed that activation of the rainfall
systems.
In both cases, the further northward intrusion of strong low-level
southerly wind across the time mean position of the Meiyu front enhanced
the rainfall activity of the front, through the moisture transport and
the generation of convective activity there. It is noted that, in
addition to the nearly stationary low-level southerly wind in the
subtropical high area toward the front, the region with relatively
strong southerly wind invaded further northward due to the eastward
extension of a synoptic-scale surface low along `40N. Distribution of
the negative relative vorticity at 500 hPa level suggests that that
surface low wound be formed associated with the heating from the ground
around the arid region in China. It is well known that the inflow of
the dry air in the middle troposphere is one of the important processes
for enhancement of the severe rainfall systems. The arid or semiarid
region in China might provide such dry air into the rainfall systems on
the Meiyu front. In addition, the present study indicates another
interesting role of the arid or semiarid areas in China in the evolution
of a meso--scale low on the Maiyu front.
Submittal Information
| Name : | Date : |
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| Organization : | Theme : |
Faculty of Education, Okayama University | |
| Address : | Presentation : |
Tsushima-naka 3-1-1, Okayama City, 700-8530 | |
| Country : | Abstract ID : |
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| Phone : | Fax : |
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| E-mail : | |
kuranos@cc.okayama-u.ac.jp | |