1990 Fiscal Year Final Research Report Summary
A Study on Generation and Maintenance of Hawaiian Rainbands
| Project/Area Number |
63044108
|
|---|
| Research Category |
Grant-in-Aid for international Scientific Research
|
| Allocation Type | Single-year Grants |
|---|
| Section | Joint Research |
|---|
| Research Institution | Kyushu University |
|---|
Principal Investigator |
TAKAHASHI Tsutomu Kyushu University, the Faculty of Science・Professor, 理学部, 教授 (20197742)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
YASUI Motoaki Kyushu University, the Faculty of Science, Research Associate, 理学部, 助手 (80220143)
|
|---|
| Project Period (FY) |
1988 – 1990
|
| Keywords | Rainbands / Squall Lines / 降水 / 氷晶 / 雨滴 |
|---|
| Research Abstract |
Data obtained from aircraft observations around the island of Hawaii during the 1985 Joint Hawaii Warm Rain Project was analyzed pertaining to the microphysical, thermodynamic and dynamic character of rainbands. Analysis focused upon rain duration and rain accumulation. The most outstanding feature of long-lasting trade-wind rainbands is that unlike other storm systems, dry air does not intrude into the main cloud system at low levels. Vertical wind profiles were the primary factor to determine the strength of rainbands. Parabolic winds were the best to form strong rainbands, attributing to the formation of strong rainbands through the transport of momentum by precipitaion.
In order to increase our understanding of Hawaiian rainbands, Hawaii Rainband Project was held again in 1990. Electra aircraft, two doppler radars as well as 50 surface networks were incorporated to this project.
In order to extend our study to west Pacific equatorial squall lines, precipitation mechanism in the squall lines at Ponape, Micronesia was investigated by the use of special radiosondes. A unique rainwater accumulation process involving frozen raindrop hail formation was found to take place in a narrow layer of altitude just above the freezing level. Three dimensional cloud model showed longer and more intense rainfall with ice even in maritime cumulus clouds.
|
