FN Archimer Export Format PT J TI Quad-polarization SAR features of ocean currents BT AF KUDRYAVTSEV, Vladimir KOZLOV, I. CHAPRON, Bertrand JOHANNESSEN, J. A. AS 1:1,2,3;2:1;3:1,4;4:3; FF 1:;2:;3:PDG-ODE-LOS;4:; C1 Russian State Hydrometeorol Univ, Satellite Oceanog Lab, St Petersburg, Russia. Inst Marine Hydrophys, Dept Remote Sensing, Sebastopol, Russia. Nansen Environm & Remote Sensing Ctr, Bergen, Norway. IFREMER, Lab Oceanog Spatiale, Plouzane, France. C2 UNIV RUSSIAN STATE HYDROMETEOROL, RUSSIA INST MARINE HYDROPHYS, RUSSIA NERSC, NORWAY IFREMER, FRANCE SI BREST SE PDG-ODE-LOS IN WOS Ifremer jusqu'en 2018 copubli-europe copubli-int-hors-europe TC 57 UR https://archimer.ifremer.fr/doc/00210/32152/30611.pdf LA English DT Article DE ;quad-polarized SAR;SAR imaging of ocean current;radar scattering;wave-current interaction;wave breaking AB A methodology is demonstrated to exploit the polarization sensitivity of high-resolution radar measurements to interpret and quantify upper ocean dynamics. This study particularly illustrates the potential of quad-polarization synthetic aperture radar (SAR) measurements. The analysis relies on essential characteristics of the electromagnetic scattering mechanisms and hydrodynamical principles. As the relaxation scale of centimeter-scale ocean surface scatters is typically small, radar signal anomalies associated with surface manifestations of the upper ocean dynamics on spatial scales exceeding 100 m are mostly dominated by nonresonant and nonpolarized scatters. These “scalar” contributions can thus efficiently trace local breaking and near-breaking areas, caused by surface current variations. Using dual copolarized measurements, the polarized Bragg-type radar scattering is isolated by considering the difference (PD) between vertically and horizontally polarized radar signals. The nonpolarized (NP) contribution associated with wave breaking is then deduced, using the measured polarization ratio (PR) between polarized signals. Considering SAR scenes depicting various surface manifestations of the upper ocean dynamics (internal waves, mesoscale surface current features, and SST front), the proposed methodology and set of decompositions (PD, PR, and NP) efficiently enable the discrimination between surface manifestation of upper ocean dynamics and wind field variability. Applied to quad-polarized SAR images, such decompositions further provide unique opportunities to more directly assess the cross-polarized (CP for HV or VH) signal sensitivity to surface roughness changes. As demonstrated, such an analysis unambiguously demonstrates and quantitatively evaluates the relative impact of breakers on cross-polarized signals under low to moderate wind conditions. PY 2014 PD SEP SO Journal Of Geophysical Research-oceans SN 0148-0027 PU Amer Geophysical Union VL 119 IS 9 UT 000343879200026 BP 6046 EP 6065 DI 10.1002/2014JC010173 ID 32152 ER EF