星载雷达波谱仪反演海浪谱的精度研究

The resolution of ocean wave spectra retrieved by space-borne real aperture radar spectrometer

介绍了星载雷达波谱仪的观测原理及误差分析模型,并在Hauser等提出的SWI M(sea wave investigation and monitoring by satellite)的基础上分析了波谱仪反演海浪谱的波长分辨率和角度分辨率。为了减小反演调制谱的波动,在数据处理过程中时域和波数域相邻单元的平均个数分别为10和8个。系统在不同的模式下工作,为了获取20°的角度分辨率,对调制谱平均次数分别取3次(模式1)、7次(模式2)、10次(模式3)。使用解析法和仿真法分析了SWI M工作在模式2时海浪谱观测的能量误差,两种方法的结果一致。对于给定的海浪条件,能量误差小于20%。

The measurement principle of a space-borne real aperture radar spectrometer and the error analysis model are introdued.The analysis of the wavelength resolution and directional resolution is presented,based on the SWIM instrument,which is proposed by Hauser D et al.To reduce the fluctuation of retrieved spectra,it is proposed to average ten adjacent independent samples in the time domain and eight in the wavenumber domain,respectively,during the data processing.And for achieving the directional resolution better than 20°,the largest number of integrated subperiod is three,seven and ten for the instrument operated in three different modes,respectively.Two methods,namely,analytical process and simulation process,are adopted to analyze the energy error of retrieved wave spectra by SWIM operated at Mode 2.The results of the two methods are in agreement,which shows that the energy error is less than 20% for certain wave conditions.