Study on wave forecasting and hindcasting method based on air-wave-sea coupled model adaptable for open sea boundary

本研究旨在发展适用于远海边界的气-波-海耦合模式海浪预报和预报，为海洋设施的可靠性设计和性能规范提供高精度和高分辨率的海浪信息。初步结果总结如下：1。结果表明，将开放边界上的方向谱作为代价函数，采用伴随波分法进行波浪后播预报的精度大大提高，计算面积显著缩小。研究了风向波的能量传递过程和输入能量和耗散源项的公式，发现白帽与风向波的能量传递密切相关。在此基础上，给出了考虑白帽对能量输入和耗散影响的计算公式。利用MM5中尺度气象模式对伊势湾海面风进行了2001年全年的模拟，并通过伊势湾海洋塔台的观测验证了其精度。利用气象模式MM5计算海面风，海浪模式WAM和SWAN计算风波，建立了一种耦合模式，并应用于伊势湾和东京湾的高分辨率海浪预报。观测结果验证了该方法的准确性和实用性。对日本周边WAM预报精度的检验开发了伴随WAM同化任意点波资料的方法，其精度在日本周边有所提高。

This study was performed to develop the wave forecasting and hindcasting based on air-wave-sea coupled model adaptable for open sea boundary, that can supply ocean wave information with high accuracy and resolution essential to reliability design and performance specification for ocean facilities. The primary results are summarized as follows :1.Development of the adjoint method for open-boundary date assimilation in wave hindcasting and forecastingIt was shown that the accuracy of the wave hindcasting and forecasting using the adjoint WAM that treats the directional spectra on the open-boundary as a cost function was greatly improved and the computation area was remarkably reduced.2.Investigation on the energy transfer process from winds to waves and formulation of the source term of input energy and dissipationWhite caps were found to be closely related to the transferred energy from winds to waves. On the basis of the results, the formulation considering the influences of the white caps was made on the input and dissipation terms of energy.Highly accurate simulation of sea surface winds using the mesoscale meteorological model MM5The simulation of sea surface winds over Ise bay using, the mesoscale meteorological model MM5 was performed for the whole year of 2001, and its accuracy was validated with observations at a marine tower station in Ise bay.Wave hindcasting and forecasting based on the coupled atmosphere and wave modelA model coupling the meteorological model MM5 to compute sea-surface winds and the wave models WAM and SWAN to compute wind waves was developed and was applied to high-resolution wave hindcasting in Ise bay and Tokyo bay. Its accuracy and utility were validated with observations.5.Examination on prediction accuracy of WAM around JapanAdjoint WAM assimilating wave data at arbitrary points was developed, and its accuracy was shown to improve around Japan.