Global spectral characteristics from 1Hz along-track altimetry

Oscar Vergara (CLS, LEGOS, France)

Event: 2020 Ocean Surface Topography Science Team Meeting (virtual)

Session: Science III: Mesoscale and sub-mesoscale oceanography

Presentation type: Type Forum

We use three years of Sea Surface Height (SSH) observations over the World Ocean to analyze its spectral characteristics. Our analyses are based on previous works that focused on the spectral slope characterization through a linear regression over a geographically dependent wavelength range, corresponding to the mesoscale wavelength range. In our current analysis, we adopt a methodology that allows for the characterization of the spectral slope, but also includes the statistical uncertainty that is contained in the wavelength range that considered to be instrumental noise, and that has an influence on the spectral shape towards geophysical spatial scales. The values of spectral slope observed are within the range of previous works, however we observe a higher spatial variability around regions where the eddy kinetic energy varies sharply, with spectral slope values that drop significantly around low energy regions. Noise level distribution is also within range of previous results, although we observe higher values in the mid latitudes (25-30%) and intertropical band. In addition, our current approach allows us to analyze (if present) the shift in spectral slope that occurs at wavelengths under 100km. Preliminary results on this topic are also presented.
Oscar Vergara