机载多普勒散射计海风海流联合反演研究

Joint retrieval of wind and current using airborne Doppler scatterometer

多普勒散射计能够获取海面后向散射系数和多普勒频移,从而实现海面风场和海表流场的同步观测。本文基于机载多普勒散射计的观测数据,对多普勒散射计海面风场和海表流场联合反演模型进行研究,并与风场流场独立反演结果进行对比。结果表明,联合反演的流场精度显著优于独立反演结果;然而以欧洲中期天气预报中心的海面风场为参考时,联合反演风场的精度略低于独立反演结果。这说明多普勒频移信息对海面风场反演的贡献不太显著,但雷达后向散射系数信息(即风场)对流场反演有积极的作用,通过联合反演算法能够更有效地消除海面风场对流场反演的影响。研究结果有助于进一步理解海面风场和海表流场反演时的相互影响,并为星载多普勒散射计的数据处理提供了参考。

Doppler scatterometer is able to measure radar backscattering coefficient and Doppler frequency over sea surface,such that it can be used to retrieve sea surface wind and sea surface current simultaneously.This paper performs a study on the joint wind and current retrieval based on the observation data from an airborne Doppler scatterometer,which results are compared with those of independent retrieval.The results indicate that the accuracy of sea surface current is significantly improved by introducing the radar backscattering coefficients into the joint inversion method,however,the accuracy of the retrieved wind field from the joint inversion method is slightly lower than that of the independent wind inversion,compared to the European Centre for Medium-Range Weather Forecasts winds.This implies that the Doppler information has little influence on the wind retrieval,while the radar backscattering coefficients(the wind)have a remarkable impact on the sea surface current retrieval.The joint inversion algorithm can mitigates the effects of sea surface wind for the current retrieval.The results of this study provide a new insight to the interplay between wind inversion and current retrieval,and also provide a reference for the data processing of spaceborne Doppler scatterometer.