Spectral decomposition of internal gravity wave sea surface height in global models
Abstract
Two global ocean models ranging in horizontal resolution from 1/12° to 1/48° are used to study the space and time scales of sea surface height (SSH) signals associated with internal gravity waves (IGWs). Frequency‐horizontal wavenumber SSH spectral densities are computed over seven regions of the world ocean from two simulations of the HYbrid Coordinate Ocean Model (HYCOM) and three simulations of the Massachusetts Institute of Technology general circulation model (MITgcm). High wavenumber, high‐frequency SSH variance follows the predicted IGW linear dispersion curves. The realism of high‐frequency motions (> ) in the models is tested through comparison of the frequency spectral density of dynamic height variance computed from the highest‐resolution runs of each model (1/25° HYCOM and 1/48° MITgcm) with dynamic height variance frequency spectral density computed from nine in situ profiling instruments. These high‐frequency motions are of particular interest because of their contributions to the small‐scale SSH variability that will be observed on a global scale in the upcoming Surface Water and Ocean Topography (SWOT) satellite altimetry mission. The variance at supertidal frequencies can be comparable to the tidal and low‐frequency variance for high wavenumbers (length scales smaller than ∼50 km), especially in the higher‐resolution simulations. In the highest‐resolution simulations, the high‐frequency variance can be greater than the low‐frequency variance at these scales.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Oct 01, 2017
- Source ID
- 10.1002/2017jc013009
Entities
People
- Alan J. Wallcraft
- Amanda K. O'rourke
- Anna C. Savage
- Brian K. Arbic
- Dimitris Menemenlis
- Gunnar Voet
- J. Thomas Farrar
- James G. Richman
- Jay F. Shriver
- Joseph Ansong
- Luis Zamudio
- Matthew H. Alford
Organizations
- California Institute of Technology
- Florida State University
- National Aeronautics and Space Administration
- National Science Foundation
- Office of Naval Research
- United States Naval Research Laboratory
- University of California, San Diego
- University of Michigan
- Woods Hole Oceanographic Institution