1987 Fiscal Year Final Research Report Summary
A study of meso-scale vortex-like convective clouds observed over the seas around Japan
| Project/Area Number |
60460048
|
|---|
| Research Category |
Grant-in-Aid for General Scientific Research (B)
|
| Allocation Type | Single-year Grants |
|---|
| Research Field |
気象・海洋・陸水学
|
|---|
| Research Institution | University of Tokyo |
|---|
Principal Investigator |
ASAI Tomio Ocean Research Inst., Univ. of Toky Professor, 海洋研究所・海洋気象部門, 教授 (80025288)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
MIURA Yuuichi Science Univ. of Tokyo Assistant, 理工学部, 助手 (00084476)
NAKAMURA Kozo Ocean Research Inst., Univ. of Toky Assistant, 海洋気象部門, 助手 (20143547)
KIMUA Ryuji Ocean Research Inst., Univ. of Toky Assistant Professor, 海洋研究所・海洋気象部門, 助教授 (20013576)
|
|---|
| Project Period (FY) |
1985 – 1987
|
| Keywords | meso-scale vortical cloud / convective cloud / convergence zone / horizontal shear / heavy snowfall / Japan Sea / 静止気象衛星 |
|---|
| Research Abstract |
Vortical convective cloud patterns in meso-scale ranging from[10km to [100km gave been frequently found over the seas around Japan, since observation by the geostationary meteorological satellite "Himawari" was available in 1987. The objectives of the present study is to elucidate seasonal and geographical distributions of meso-scale vortical convective clouds and mechanism of their development besed on an observational study and laboratory and numercal experiments.
The results obtained so far are summarized as follows.
(1) Statistical analyses of satellite cloud pictures show two preferred areas in the Sea of Japan in winter where meso-scale vortical clouds are most frequently observed : 1) east of Korea peninsula and 2) west of Hokkaido Island. These vortical clouds gaving cyclonic vorticity and life-time of several hours move to southeast in a speed of 10ms^<-1> and some of them vanish just after landing to coastal regions of Japan.
(2)Band clouds accompanying horizontal convergence and cyclonic shear are observed and the vortical clouds are often formed in the bands : one is a convergence zone between northerly wind from Siberia and westerly wind from Korea peninsula and the other is a convergence zone between northwesterly from Siberia and northeasterly from Hokkaido. This suggests that meso-scale vortical disturbances may be formed favorably in the convergence zones.
(3) A well-developed trough or a cold vortex in the upper troposphere and a northwesterly monsoon in the lower tropposphere provides a deep potentially unstable layer over the Sea of Japan. This is favorable for development of meso-scale vortical convective clouds in association with topographically induced convergence and shear zones.
|
