Satellite altimetry backscattering coefficient differences between Ku and Ka bands over the Arctic Ocean

Fanny Piras (CLS, France)


Jean-Christophe Poisson (CLS, France); Pierre Prandi (CLS, France)

Event: 2014 SARAL/AltiKa workshop

Session: Land ice and Sea ice

Presentation type: Type Poster

In the beginning of the year 2013 the SARAL/AltiKa mission was launched. This platform embarks a new type of altimeter, AltiKa, operating in Ka band. Considering the fact that previous satellite altimetry missions operated in the Ku frequency, this is a new step in spatial altimetry. The calibration/validation activities already showed the very good performance of the mission over ocean and even better than some previous Ku-band missions. But over ice surfaces, and especially above the Arctic sea ice, it is well known that measurements in Ka-band have a different behavior from those in Ku-band and particularly in terms of roughness
In this study, SARAL/AltiKa is compared to Cryosat-2 over the Arctic Ocean's sea-ice in order to investigate backscattering differences between the Ku and Ka bands. Crossovers between the two missions are computed in order to draw comparisons where ice is in similar state. Given the high variability of the surface properties, crossovers with very short time delays are selected (typically less than 15 minutes) to compare backscattering coefficient. At these points, Cryosat and SARAL/AltiKa waveforms are also compared, and the results of different retracking algorithms are investigated
Auxiliary data like OSI-SAF or LandSat images are used to provide information about the sea-ice surface state (e.g. ice concentration, ice type).
Fanny Piras