Numerical Simulation Of Multi-scale Temporal Variations And Coupling Mechanism Of Sea Surface Wind And Wave Fields In The Offshore Area Of The Northern Jiangsu Province In 2016

The multi-scale variation and coupling mechanism of wind and wave fields are studied by uncoupling and coupling models in this paper.The sea surface wind and wave fields in the offshore area of the northern Jiangsu Province are simulated during 2016 by applying high-resolution atmospheric WRF(Weather Research and Forecast)and wave numerical models SWAN(Simulating Waves Nearshore).In order to evaluate the simulation performance,the model results are compared with satellite altimetry data,scatterometer wind data,reanalysis products and buoy data.The analysis of the simulation results shows the presence of multi-scale temporal variations in the sea surface wind and wave fields: seasonal,diurnal and intra-seasonal scales.The sea surface wind,significant wave height and swell are larger in winter and fall than in spring and summer.The northwestern(southeastern)wind and wave prevail in winter(summer).Moreover,significant diurnal variations in the wind and wave fields,and seasonal variations in the diurnal signals are observed.It is found that the diurnal variations are stronger nearshore than offshore.Meanwhile,the offshore area of Jiangsu Province is subject to the threats of strong synoptic processes,such as cold waves and tropical cyclones.The uncoupled simulation of wind-induced waves points to the multi-scale variation characteristics of wind affecting the multi-scale variation characteristics of waves.The atmosphere influences the wave field through the sea surface wind field,and the wave field displays a fast response to changes in the wind field.Furthermore,the COAWST modeling system is applied to compare two wave-induced stress parameterization schemes.The results are also compared with satellite altimeter data,scatterometer data,reanalysis data and buoy data.It was found that the wave-induced stress parameterization in the coupled model significantly improved the simulation results.Based on the model results,the effects of waves on different atmospheric elements of the coupled model are systematically analyzed.Seasonal changes are observed in the effects of waves on the atmosphere.The waves increase(decrease)the sea level pressure,decrease(increase)the potential temperature and increase(decrease)the wind speed in the lower layer in winter(summer).Also,the effects of waves on the atmosphere gradually decrease as height increases,usually below 3000 m;The influence of the atmosphere on waves is greater using Drennan parameterization scheme than that of Taylor's scheme.In winter,the atmosphere increases the effective wave height and swell wave height offshore.In summer,the atmosphere increases the effective wave height and swell wave height offshore and in the southern sea area.The impact of the atmosphere due to wave and the coupling mechanism of atmosphere and wave is analyzed.