Multi-polarization radar backscatter signatures of internal waves at L-band. Issue 6 (19th March 2022)

• Record Type: Journal Article
• Authors: de Macedo, C. R.; da Silva, J. C. B.; Buono, A.; Migliaccio, M.
• Is Part Of: International journal of remote sensing. Volume 43:Issue 6(2022)
• Page Start: 1943
• Page End: 1959
• Publication Date: 2022-03-19
• Subjects: Internal waves -- backscattering -- polarization -- SAR -- L-Band; Remote sensing -- Periodicals; Télédétection -- Périodiques; 621.3678
• DOI: 10.1080/01431161.2022.2050435
• Languages: English
• ISSNs: 0143-1161

Abstract

ABSTRACT: In this study, the scattering mechanisms associated to internal waves (IWs) are investigated at L-band. IWs represent key geophysical factors for sea-air heat exchange and play a paramount role in the biological primary production and in the understanding of the evolution of climate ecosystem. In addition, a better understanding of IWs microwave scattering mechanisms can improve the modeling capability and, therefore, can boost the development on advanced synthetic aperture radar (SAR)-based added-value products to mitigate the risk for offshore drilling operations and aquaculture activities associated to IWs. The analysis of L-band multi-polarization SAR scattering of IWs under the influence of surface current straining is performed using a meaningful full-polarimetric Advanced Land Observing Satellite Phased Array type L-band 1 SAR data set collected over IWs observed under different imaging and wind conditions. Time and space co-located ancillary information is also available. Experimental results demonstrate that the non-polarized scattering mechanisms constitute a significant contribution to the total IW backscattering, especially in the case of surface current gradients owing to IWs (about 48–57%). It is also found that the non-polarized scattering contribution associated to IW concentrates along the wave crests, i.e. it is at least 60% larger than the one observed along the wave troughs. In addition, considering the IW traveling directions relative to that of the wind, the non-polarized scattering contribution associated to IWs is more remarkable at upwind direction while it is less significant at down/crosswind directions. The non-polarized scattering mechanisms also calls for a modulation induced by IWs which is much more significant, i.e. at least three times, that the one that characterizes the polarized scattering mechanism.