Altimetric wavenumber spectra: noise floors and resolution capability

Oscar Vergara (LEGOS/OMP, France)

CoAuthors

Rosemary Morrow (LEGOS/OMP, France); Isabelle Pujol (CLS Space Oceanography, France); Gerlad Dibarboure (CNES, France)

Event: 2017 Ocean Surface Topography Science Team Meeting

Session: Quantifying Errors and Uncertainties in Altimetry data

Presentation type: Type Oral

Recent progress in satellite altimetry has greatly improved the observability of mesoscale structures in the ocean. Here we analyze the noise levels and observable spatial scales for the global ocean using the wavenumber spectra of the three-year SARAL/Altika 1Hz Sea Surface Height (SSH) along-track measurements. We observe that noise estimations (for the wavelength range 15-30 km) tend to deviate from a purely white noise spectrum in regions of low eddy energy, and in particular inside the tropical band (15°S-15°N). Noise levels also vary seasonally, with an overall higher noise level during winter months in comparison to summer. The capability for resolving fine spatial scales also varies as a consequence of the noise level seasonality. During winter months, the observable wavelength reduces by about 5 to 20 km with respect to summer season. In general, these variations are less important in western boundary current systems in comparison to less energetic current systems, given the relatively favorable signal to noise ratio that is found in western boundary current systems.
 

Oral presentation show times:

RoomStart DateEnd Date
Symphony II Wed, Oct 25 2017,15:00 Wed, Oct 25 2017,15:20
Oscar Vergara
LEGOS/OMP
France
oscar.vergara@legos.obs-mip.fr