Hazard Mapping for Storm Surge and Factorial Analysis of Environmental Variables over Ariake and Yatsusiro -Sea

（1）建立了分析潮滩及其冲沟形态的数值方法。基于风暴潮、高波和潮汐的相互作用，开发了风暴潮风险图及其最大发生概率预测。采用准三维海洋环流模式POM（Princeton Ocean Model）模拟了具有复杂底地形的北部湾的海流和物质输运。POM中平流计算的数值格式由中心差分改为TVD格式，以提高其可移植性。试验模拟表明了平流项修正方案的有效性。结合风暴潮最大发生概率预报，提出了减轻风暴潮灾害的对策。（2）为了绘制沿着有明-白井沿岸的风暴潮危险图，利用中尺度模式（PSU/NCAR MM 5）计算了海面风场。模拟进行了一年多， ...更多信息 1999年，并将计算风场与观测风场进行了比较。模拟成功地再现了受周围复杂地形影响的近地面风场。利用模式模拟的风场，可望对风暴序列作较准确的预报。提出了作为大气与近海能量传递界面的白浪耗散应力数学模型。利用该界面模型，建立了风-浪-流数值系统（WWC系统），该系统综合了风应力（风场）、白顶破碎应力（浪场）和底应力（流场）之间的关系。该系统还考虑了波浪浅化引起的白顶耗散应力的增强效应。(3)In为了阐明潮滩地貌变化与季节平均海平面变化的关系，本研究对潮滩底剖面变化进行了野外调查和数值分析。在现场调查中发现，6 ~ 10月平均潮位上升约40 cm。此外，为了评估潮滩地形响应的主要原因，二次多项式方法已被提出用于近似的跨海岸剖面。多项式的三个参数和外力之间的关系进行了研究。因此，潮汐运动是占主导地位的潮滩，其中有凸向上的配置文件。在比目前观测间隔更短的时间尺度上，风浪和河流流量的支配可能变得重要。这保证了未来在风暴和台风前后的观测。（4）积累了有明海的水质数据和微生物信息，为有明海的富营养化评价提供了依据。绿川河口表层海水叶绿素a浓度高于近海。夏季地表水细菌数量明显高于其他季节。此外，还对海水中悬浮物的粒度变化进行了分析，发现大多数样品中悬浮物的粒度分布有两个主要峰，一个在0.4 ~ 0.5 μm之间，另一个在10μm左右。叶绿素a浓度与颗粒变化的相关性不明显，但与其它指标的相关性在不同的时间段内存在。少

(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