第一猜测谱运行范围对MPI方法SAR海浪方向谱反演结果的影响

On the Effects of the Region for Obtaining First Guess Spectra on the Directional Ocean Wave Spectra Retrieved by SAR with MPI Algorithm

欧空局相继发射的多颗海洋卫星专门设计了波模式SAR数据,提供了27a全球二维海浪的连续观测。批量数据的精确反演对于海浪研究、海浪预报、海洋产业和军事活动至关重要。本文使用ORSI/OUC研发的基于MPI方法的卫星SAR海浪方向谱反演程序,研究了第一猜测谱运行范围对反演结果的影响。对西北太平洋17 000幅波模式SAR数据进行批量处理,发现反演程序中MPI非线性反演方法第一猜测谱的运行范围对反演结果的能量密度、波长、传播方向和谱形结构有程度不同的影响,文中给出一个实例。进而选择10°S^70°N,90°E^170°W运行范围,利用NOAA/NDBC浮标数据,对17 000个反演的海浪方向谱数据进行同步印证,相对误差为4.5%,均方根误差为0.52m,偏差为0.01m。

The wave mode of SAR were deliberately designed on the earth observation satellites sequentially launched by ESA,which has been providing the continuous observations of global two-dimensional ocean waves for 27 years.Batch accurate retrieval of ocean wave spectra from SAR data is essential for ocean wave researches,ocean wave forecasting,ocean engineering and military activities.Based on the program developed by ORSI/OUC for retrieving ocean wave spectra from SAR data with MPI algorithm,the effect of the region for obtaining first guess spectra on retrieved ocean wave spectra is studied.It is found by batch processing 17000 wave mode SAR imagettes acquired in Northwest Pacific that the region for getting first-guess spectra needed in MPI nonlinear retrieval algorithm has different effects on the energy,wave length,propagation direction and shape of the retrieved spectra.An example is given to illustrate that.By setting the region to 80°×100°(10°S^70°N,90°E^170°W),17000 spectra are reprocessed and validated with buoy measurements from NOAA/NDBC.The relative error of 4.5%,the rmse(root-meansquare-error)of 0.52 mand the bias of 0.01 mare obtained by the validation.