Simulation Error of Wave Models Forced by Reanalysis Wind Data in the South China Sea

In this paper,WAVEWATCH III wave model,which is individually forced by ERA-40,CFSR and NCDC reanalysis wind products,is used to obtain wave data in the South China Sea.Based on the global satellite altimeter wave height data and Chinese coastal buoy wave data,the three sets of modeling wave results induced by different wind products are compared and analyzed.It is revealed that the error characteristics of the three reanalysis wind products are obviously different.The ERA-40 wind data underestimate wave height and the CFSR wind field is very suitable for simulating the wave climate in the common weather.The NCDC wind data is more capable to capture large wave height series.Generally,according to the validation based on buoy data and altimeter wave data,both CFSR and NCDC reanalysis wind products can make good simulation of the main wave series in the South China Sea.Referring to the hindcasting wave data by NCDC wind,the error of WAVEWATCH III are investigated.It is found that in the north of the South China Sea where typhoons occur frequently,wave model tend to underestimate large wave heights.While in the south of the South China Sea,where the monsoon has a significant impact,wave model is prone to overestimate waves.Although the wave height errors vary from the north to the south,the WW3 wave model underestimate wave period in the whole South China Sea.According to the error characteristics,different reanalysis wind products should be used to conduct different research.For example,NCDC reanalysis wind is more suitable for definition of engineering wave standards and CFSR reanalysis wind is more capable to investigate long-term wave climate.The tendency of errors provides helpful clues for smart use of the hindcasting wave data.It is proved that all of the reanalysis wind products utilized in this paper is prone to underestimate extreme waves,especially those waves induced by intense typhoons,which is mainly due to the 6-hour interval of the wind field.It should be very cautious to use high quantiles of the hindcasting wave results.The simulation error trend of satellite altimeter wave height in the oceans of 2°around a buoy is similar with that of the buoy wave height simulation.The statistical quantiles of buoy wave height data are generally equal with those of satellite altimeter data extracted by the“2 Degree Method”.Especially,for the low quantiles,similar statistical results can be deduced from the data by“2 Degree Method”and the buoy data.In those oceans where there is not long-term buoy data,the data set by“2 Degree Method”is a good alternative to buoy data for long-term wave climate research.