Storm surges prediction in terms of a typhoon model which includes effects of land topography and roughness

在大坂湾这样被群山环绕的封闭小流域中进行风暴潮模拟是一个困难的问题，特别是在风场预测或模拟方面，它受到复杂地形的影响。日本的台风场计算传统上采用Fujita台风模式，Yoshizumi（1968）提出了一个考虑地面摩擦的台风风场模式。本文用它来估计考虑摩擦影响的台风风场。由于Yoshizumi模式所描述的风场不包括地形的影响，因此本研究中我们引入了“MASCON”（质量守恒）模式来考虑地形对风速的减速和加速的影响，这是一个结合Yoshizumi模式和MASCON模式的新的台风风场模式。采用Schloemer方程建立了对称气压场，并采用新的台风风场模式（MASCON-Y模式）对风暴潮进行了数值模拟，对风暴潮预报数值模式的发展进行了研究。通过对大坂湾9426、6523、6118号台风和伊势湾伊势湾台风引起的风暴潮的后报，检验了该方法的有效性。

Storm surge simulation in small closed basins surrounded by mountains such as Osaka Bay is difficult-especially in the wind field prediction or simulation, which is affected by complex land topography. Fujita's typhoon model has been traditionally employed for the estimation of typhoon fields in Japan.Yoshizumi (1968) proposed a typhoon wind field model which describes the lower-layr winds in a moving typhoon with consideration of surface friction. It is employed here to estimate the typhoon wind field taking into account the effect of friction. As the wind field described by Yoshizumi's model does not include the effect of land topography, we introduce the 'MASCON' (mass conservation) model to take into account the effects of deceleration and acceleration of wind velocity due to land topography, in this research.This is a new model of typhoon wind field which is developed here by combining the Yoshizumi's and MASCON models. The pressure field is formulated by Schloemer's equation which assumes a symmetric pressure pattern.A study on advancement in numerical models for storm surge prediction was carried out by means of numerical simulations of storm surges in which new model of typhoon wind field (MASCON-Y Model) was employed. Its validity was examined by hindcast of storm surges caused by Typhoons 9426,6523 and 6118 in Osaka Bay, the Isewan Typhoon in Ise Bay.