AMI-wind measurements compared to SSM/I interpretations over Arctic Sea ice

From November 1992 to June 1993, backscattering coefficients, σ°, at 40° incidence angle were computed using the backscatter measurements of ERS-1´s scatterometer, the AMI-Wind. Maps σ° were compared to those of different SSM/I parameters: brightness temperatures, spectral gradient ratio, polarization ratio, first-year and multi-year ice concentrations: During winter months, the higher values of σ° over the Arctic ocean are closely related to multi-year ice concentrations given by the NASA Team algorithm. In the first part of May, a strong and rapid decrease of the spectral gradient ratio near the coast of Siberia leads to the sudden appearance of multi-year ice there, in contradiction with the backscatter values, which remain low