Assessment of Wind Speed Estimation From C-Band Sentinel-1 Images Using Empirical and Electromagnetic Models - ENSTA Bretagne - École nationale supérieure de techniques avancées Bretagne Accéder directement au contenu
Article Dans Une Revue IEEE Transactions on Geoscience and Remote Sensing Année : 2018

Assessment of Wind Speed Estimation From C-Band Sentinel-1 Images Using Empirical and Electromagnetic Models

Ali Khenchaf
Fabrice Comblet
Carole Nahum
  • Fonction : Auteur
DGA

Résumé

Surface wind speed estimation from synthetic aperture radar (SAR) data is principally based on empirical (EP) approaches, e.g., CMOD functions. However, it is necessary and significant to compare radar backscattering modeling based on EP and electromagnetic (EM) approaches for enhancing the understanding of the physical processes between radar signal and sea surface, which is important for the design of radar sensors (e.g., cyclone global navigation satellite system). Indeed, through comparisons, it is worth noticing that the scattering of wave breaking is not taken into account in the physical modeling of radar backscattering. Surface wind speed is selected here as a reference parameter for investigating the difference between EP and EM models, due to its important role in radar backscattering modeling. In addition, wind speed estimates can be easily compared to in situ measurements. For EP approach, CMOD5.N and Komarov's model are selected for wind speed estimation from Sentinel-1 images. The CMOD5.N can offer wind speed estimates up to 25-35 m/s, while wind speed estimation based on Komarov's model does not require wind direction input. For EM approach, the asymptotic models, i.e., composite two-scale model, small-slope approximation (SSA), and resonant curvature approximation (RCA), are investigated for wind speed retrieval. They are studied with two models of surface roughness spectrum: semi-EP spectrum and EP model. In general, normalized radar cross section (NRCS) calculated by CMOD5.N and SSA/RCA is quite similar for incidence angles below 40° in vertical polarized and below 30° in horizontal polarized. For larger ones, significant NRCS deviations between two approaches are demonstrated, due to the lack of wave breaking scattering in EM models. As a result, wind speed estimates by CMOD5.N and SSA/RCA are very close for low and moderate incidence angles, while SSA-/RCA-based wind speeds are overestimated for larger ones.
Fichier non déposé

Dates et versions

hal-01833448 , version 1 (09-07-2018)

Identifiants

Citer

Tran Vu La, Ali Khenchaf, Fabrice Comblet, Carole Nahum. Assessment of Wind Speed Estimation From C-Band Sentinel-1 Images Using Empirical and Electromagnetic Models. IEEE Transactions on Geoscience and Remote Sensing, 2018, 56 (7), pp.4075 - 4087. ⟨10.1109/TGRS.2018.2822876⟩. ⟨hal-01833448⟩
184 Consultations
0 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More