Sea Surface Height Variability In The 30-120 Km Wavelength Band From Altimetry Along-Track Observations

Reprocessed altimetry along-track sea surface height (SSH) observations from multiple missions are analyzed for the SSH variability in the 30-120 km wavelength band. This band of variability is missing in the widely used global multi-mission mapped SSH data set, known as the Archiving, Validation and Interpretation of Satellite Oceanographic Data SSH product. The SSH variability is derived from along-track SSH variance spectra after subtracting noise floors, and its global spatial patterns are consistent among the missions and the output of a high-resolution ocean general circulation model simulation. High SSH variability in the 30-120 km wavelength band is found in the intratropics of all ocean basins (25 degrees S-25 degrees N), the western boundary current outflow regions, and in five regions along the Antarctic Circumpolar Current: Agulhas Retroflection zone, Kerguelen Plateau, Macquarie Ridge, Pacific Antarctic Ridge, and Drake Passage. The average slope of the along-track SSH spectra in the 30-120 km wavelength band in the intratropics falls between -2.14 and -1.56, consistent with the Garrett-Munk spectral slope. The spatial patterns of the SSH variability could be used as a metric to evaluate high-resolution numerical models and to shed light on what to expect from future high-resolution altimetry missions.