Internal gravity wave contributions to global sea surface variability
Anna Savage1, Brian K Arbic1, James G Richman2, Jay F Shriver3, Maarten C Buijsman4, Luis Zamudio5, Alan J Wallcraft6 and Hari Sharma7, (1)University of Michigan Ann Arbor, Ann Arbor, MI, United States, (2)COAPS, Florida State University, Tallahassee, FL, United States, (3)US Naval Research Laboratory, Stennis Space Center, MS, United States, (4)University of Southern Mississippi, Stennis Space Center, MS, United States, (5)Florida State University, Tallahassee, FL, United States, (6)Naval Research Laboratory, Stennis Space Center, MS, United States, (7)Portage Northern High School, Portage, MI, United States
Abstract:
High-resolution (1/12th and 1/25th degree) 41-layer simulations of the HYbrid Coordinate Ocean Model (HYCOM), forced by both atmospheric fields and the astronomical tidal potential, are used to construct global maps of sea-surface height (SSH). The HYCOM output has been separated into steric, non-steric, and total sea-surface height and the maps display variance in subtidal, tidal, and supertidal bands. Two of the global maps are of particular interest in planning for the upcoming Surface Water and Ocean Topography (SWOT) wide-swath satellite altimeter mission; (1) a map of the nonstationary tidal signal (estimated after removing the stationary tidal signal via harmonic analysis), and (2) a map of the steric supertidal contributions, which are dominated by the internal gravity wave continuum. Both of these maps display signals of order 1 cm2, the target accuracy for the SWOT mission. Therefore, both non-stationary internal tides and non-tidal internal gravity waves are likely to be important sources of “noise” that must be accurately removed before examination of lower-frequency phenomena can take place.
