| Project/Area Number |
13358005
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (A)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 展開研究 |
|---|
| Research Field |
Natural disaster science
|
|---|
| Research Institution | KUMAMOTO UNIVERSITY |
|---|
Principal Investigator |
TAKIKAWA Kiyoshi Kumamoto University, Research and Education Center of Coastal Environmental Science, Professor, 沿岸域環境科学教育研究センター, 教授 (80040450)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
YAMADA Fumihiko Kumamoto University, Dept. of Civil and Environmental Eng., Associate Professor, 工学部, 助教授 (60264280)
HARADA Hiroyuki Kumamoto University, Dept. of Civil and Environmental Eng., Associate Professor, 工学部, 助教授 (20222234)
FURUKAWA Kenji Kumamoto University, Dept. of Civil and Environmental Eng., Professor, 工学部, 教授 (60029296)
TANAKA Kennji Kumamoto University, Dept. of Civil and Environmental Eng., Research Assistant, 工学部, 助手 (30315288)
KAKINOKI Tetsuya Kobe City College of Technology, Research Associate, 都市工学科, 講師 (50353298)
田淵 幹修 (田渕 幹修) 熊本大学, 工学部, 講師 (40037966)
|
|---|
| Project Period (FY) |
2001 – 2003
|
| Project Status |
Completed (Fiscal Year 2003)
|
| Budget Amount *help |
¥39,650,000 (Direct Cost: ¥30,500,000、Indirect Cost: ¥9,150,000)
Fiscal Year 2003: ¥5,070,000 (Direct Cost: ¥3,900,000、Indirect Cost: ¥1,170,000)
Fiscal Year 2002: ¥17,420,000 (Direct Cost: ¥13,400,000、Indirect Cost: ¥4,020,000)
Fiscal Year 2001: ¥17,160,000 (Direct Cost: ¥13,200,000、Indirect Cost: ¥3,960,000)
|
|---|
| Keywords | Environment of Ariake and Yatsushiro Sea / Environment of Estuary / Richness index of Tidal Flat / Effect of Bioturbation on Denitrification rate / Denitrification of Tidal Flat / Environmental Changesi of the Ariake Sea / Environmental Use Value of Ariake Tidal Flat / Storm surge and Height water waves / 有明・人代海の環境 / 干潟の底質土特性 / 干潟の浄化機能 / 降雨流入の海域環境への影響 |
|---|
| Research Abstract |
(1)Numerical methods for analyzing the form of tidelands and their gullies were developed. Hazard Mapping for Storm Surge based on Interaction between Storm Surges, High Waves and Tide, and Their Maximum Occurrence Prediction were developed. Quasi-three dimensional ocean circulation model POM (Princeton Ocean Model) was applied to the simulation of current and material transport in the bay, which has complex bottom topography. Numerical scheme for advection computation in POM was changed from the central difference to TVD scheme to improve its transportability. Test simulation made clear the effectiveness of the modified scheme m advection term. Considering the Maximum Occurrence Prediction of Storm Surge, the Countermeasure for decrease the disaster of Storm Surge were performed.
(2)Toward the drawing of storm serge hazard map along the Ariake-Shiranui coast, sea surface wind was computed using a meso-scale eteorological model (PSU/NCAR MM5). The simulation was conducted over one year,
… More
1999, and the computed wind are compared with observation. The simulation successfully reproduced the near surface wind affected by the surrounding complex topography. It is expected that the accurate storm serge prediction is possible by the use of model simulated wind field. A mathematical model of whitecaps dissipation stress was proposed as an energy transfer interface between atmosphere and coastal ocean. Using tins interface model, numerical Wind-Wave-Current System (WWC System) was established, in which the relation between wind stresses (wind field), whitecap breaker stresses (wave field) and bottom stresses (current field) were integrated. Enhancing effects of whitecap dissipation stress due to wave shoaling was also taken into consideration in the system.
(3)In order to clarify the relationship between the morphological changes and the seasonal mean sea level changes, the present study obvious the results of field survey and numerical analysis about bottom profile changes of the intertidal flats. In the field survey, it is found that the average tide level rose about 40 cm from June to October. Also, in order to evaluate the dominating causes of morphological response on the tidal flats, quadratic polynomial approach has been proposed for approximation of cross-shore profiles. A relationship between three parameters of the polynomial and external forces has been examined. Consequently, tidal motions are dominant for tidal flats, which have convex-upwards profiles. A domination of wind waves and river discharges can become important at a time scale that is shorter than the present observation intervals. Tins warrants future observations at before and after both storm and typhoon conditions.
(4)The water quality data and the information on microorganisms in Ariake Sea were accumulated, in order to evaluate the eutrophication in Ariake Sea. The chlorophyll-a (Chl-a) concentration in surface seawater at the estuary of Midori River was higher than it offshore. The bacterial number in surface water was higher in summer than in the other season. Additionally, the granular variation of suspended solids in seawater was analyzed, and two dominant peaks were shown in most of samples ; one is at the range of 0.4 to 0.5 μm and the other is around 10μm. The relationship between the Chl-a concentration and the granular variation pattern was not observed, but those between Chl-a concentration and the others were observed in various. Less
|
