Study on Modelling the Air-Sea Boundary Processes in Unsteady and Non-Uniform Field by Expanding the TOHOKU Wave Model

非定常、非均匀场中海气边界过程的数值模拟是研究大尺度海气相互作用的一项基本任务。这一课题需要解决的问题包括：（1）阐明Bulk公式中的阻力系数和其它系数，以及气流粗糙度参数Z<@D20@>D2，除与风条件有关外，还与海况或风浪条件有关：（2）在海面蒸发和热交换的定量表达式中适当地考虑海水水滴的影响;（3）将上述两项结合起来，建立一个合适的波浪预报模式，从而建立海气通量的广域分布的表达方式。对于第（1）项，对于纯风浪，阐明了局部平衡的详细结构，即风浪、湍流、空气和水摩擦速度之间的关系。本文应用局部平衡概念，对悉尼大学一位同事在Bass海峡强风和风浪条件下的资料进行分析，有力地支持了我们早先提出的Z<@D20@>D1 = gamma u<@d2*@>d2/sigma<@d2p@>d2，其中gamma = 0.025，u<@d2*@>d2是空气摩擦速度，以及σ d2是风浪谱峰值角频率。对于第（2）项，给出了一个新的公式，用于计算风浪表面海水液滴在海面附近的产生率和浓度。对于第（3）项，我们的TOHOKU波浪模式在更复杂的条件下的应用取得了一些进展。

Modelling of the air-sea boundary processes in unsteady, non-uniform field is a fundamental task for the elucidation of large-scale air-sea interactions. Elements to be solved for this subject include (1) to elucidate the dependence of drag and other coefficients in Bulk formulas, or the air-flow roughness parameter, Z<@D20@>D2, on the sea state or wind wave conditions in addition to the wind conditions; (2) to include properly the effect of sea-water droplets in quantitative expressions of sea-surface evaporation and the heat exchange; (3) to establish the way of expression of broad-area distribution of air-sea fluxes by incorporating the above two items together with an appropreate wave prediction model. As to the item (1), detailed structure of the local equilibrium, or the relations among wind waves, turbulence, air and water friction velocity, has been elucidated for pure wind waves. By using the local equilibrium concept, applied to data under strong wind and wind-wave conditions in Bass Strait obtained by a Sydney University colleague, a strong support has been given for our earlier proposal of Z<@D20@>D1 = gamma u<@d2*@>d2/sigma<@d2p@>d2, where gamma = 0.025, u<@d2*@>d2 is the air friction velocity, and sigma<@d2p@>d2 the wind-wave spectral peak angular frequency. For item (2), a new formulation has been given for the rate of production and concentration near the sea surface of sea-water droplets from wind-wave surfaces. For item (3), some progress has been made for the application of our TOHOKU Wave Model to more complicated conditions.