Ku-/Ka-Band Extrapolation of the Altimeter Cross Section and Assessment With Jason2/AltiKa Data

Charles-Antoine Guérin (1) , Jean-Christophe Poisson (2) , Fanny Piras (3) , Laiba Amarouche (2) , Jean-Claude Lalaurie (4)

1 MIO - Institut méditerranéen d'océanologie
2 CLS - Collecte Localisation Satellites
3 EOST - Ecole et Observatoire des Sciences de la Terre
4 CNES - Centre National d'Études Spatiales [Toulouse]

A simple extrapolation technique is proposed for the intercalibration of the Ku- and Ka-band altimeter data based on a recent analytical scattering model referred to as “GO4.” This method is tested with AltiKa and Jason2-Ku altimeters using one year of reprocessed data with the improved retracking algorithm ICENEW. The variations of the normalized radar cross section with respect to the main oceanic parameters are investigated in the Ku and Ka bands; the latter band is shown to have an increased sensitivity to wind speed, significant wave height as well as sea surface temperature. As a by-product of this analysis, we derive an original expression for the swell impact on the mean square slope, which allows to correct the GO4 model for the contribution of long waves. We show that the Ku/Ka prediction agrees within 0.25 dB with the respective levels of AltiKa and Jason2-Ku cross sections at wind speed larger than 4 m/s.

Domains: Ocean, Atmosphere

Charles-Antoine Guérin, Jean-Christophe Poisson, Fanny Piras, Laiba Amarouche, Jean-Claude Lalaurie. Ku-/Ka-Band Extrapolation of the Altimeter Cross Section and Assessment With Jason2/AltiKa Data. IEEE Transactions on Geoscience and Remote Sensing, 2017, 55 (10), pp.5679 - 5686. ⟨10.1109/TGRS.2017.2711863⟩. ⟨hal-01731117⟩