Sea Surface Height Variability in the 30–120 km Wavelength Band From Altimetry Along‐Track Observations

Abstract

AbstractReprocessed 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°S–25°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.