A Study on the System for the Estimation of Extreme Waves Using a Stochastic Low Model

在假设低压系统中的气压分布近似为椭圆分布的假设下，建立了一个随机低压模型，该模型可以再现低压的9个参数，即低压的中心位置、低压的中心压力、远场压力、压力等值线长轴的倾角和低压的四轴半径。该模式是基于对过去32年西北太平洋天气图收集到的718个低压系统的参数特征进行统计分析的基础上。随机性。低气压模式再现了实际低气压特征的平均值和标准差的特征。西北太平洋地区气压和风速极值分布的模拟数据结合了随机低压模式、椭圆气压分布模式和梯度风模式的模拟数据，与基于ECMWF(欧洲中期天气预报中心)气压和风分析数据的极值相对应。日本沿海和太平洋沿岸日本海浪观测点的返回波高由随机低气压模式估计的极端海浪和风速估计系统组成。浅海高地形分辨率的单点波后投模型和极值分析模型与观测数据估算的回波高度比较吻合。在不受陆地和面向公海的遮挡作用影响的情况下，根据在深水网格点上使用波浪后投模型的系统估计的返回波高度与基于浅水网格点模型的返回波高重合。

A stochastic low pressure model which reproduces 9 parameters of a low pressure-that is, a center position, central pressure of a low, far field pressure, inclination angle of the long axis of a pressure contour and radii of a low for orthogonal 4 axeson the assumption that the air pressure distribution in a low pressure system is approximated with elliptic distribution is developed. This model is based on the statistical analysis of parametric properties of 718 low pressure systems gathered from weather charts over the Northwestern Pacific Ocean for the past 32 years. The stochastic. low pressure model reproduces the characteristics of mean value and also a standard deviation of a characteristic of actual low pressures.Distribution of extreme value of air pressure and wind speed over the Northwestern Pacific Ocean based on simulated data that combined the stochastic low pressure model, elliptic air pressure distribution model and gradient wind model correspond with the extreme value based on ECMWF (European Center for Medium-Range Weather Forecasts) air pressure and wind analysis data.Return wave height at Japanese wave observation points along the Japan Sea coast and the Pacific Ocean coast estimated by the "System for the Estimation of Extreme Waves using a Stochastic Low Model" consists of the stochastic low pressure models a wind estimation model, wave hindcast model at a single point with high topographical resolution in shallow water and extreme value analysis model correspond comparatively with the return wave height estimated by the observation data. Return wave height estimated on the basis of the system that uses a wave hindcast model over grid points in deep water coincides to return wave height based on the point model in shallow water, in cases that are not affected by the sheltering effects of the land and that face the open sea.