Observations of the dispersion characteristics and meridional sea level structure of equatorial waves in the Pacific Ocean
Farrar, J. Thomas
MetadataShow full item record
Spectral techniques applied to altimetry data are used to examine the dispersion relation and meridional sea level structure of wavelike variability with periods of about 20 to 200 days in the equatorial Pacific Ocean. Zonal wavenumber–frequency power spectra of sea surface height, when averaged over about 7°S–7°N, exhibit spectral peaks near the theoretical dispersion curves of first baroclinic-mode equatorial Kelvin and Rossby waves. There are distinct, statistically significant ridges of power near the first and second meridional-mode Rossby wave dispersion curves. Sea level variability near the theoretical Kelvin wave and first meridional-mode Rossby wave dispersion curves is dominantly (but not perfectly) symmetric about the equator, while variability near the theoretical second meridional-mode Rossby wave dispersion curve is dominantly antisymmetric. These results are qualitatively consistent with expectations from classical or shear-modified theories of equatorial waves. The meridional structures of these modes resemble the meridional modes of equatorial wave theory, but there are some robust features of the meridional profiles that were not anticipated. The meridional sea level structure in the intraseasonal Kelvin wave band closely resembles the theoretically expected Gaussian profile, but sea level variability coherent with that at the equator is detected as far away as 11.75°S, possibly as a result of the forced nature of these Kelvin waves. Both first and second meridional-mode Rossby waves have larger amplitude in the Northern Hemisphere. The meridional sea level structure of tropical instability waves closely resembles that predicted by Lyman et al. using a model linearized about a realistic equatorial zonal current system.
Author Posting. © American Meteorological Society, 2008. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Physical Oceanography 38 (2008): 1669-1689, doi:10.1175/2007JPO3890.1.
Showing items related by title, author, creator and subject.
Mass-induced sea level change in the northwestern North Pacific and its contribution to total sea level change Cheng, Xuhua; Li, Lijuan; Du, Yan; Wang, Jing; Huang, Rui Xin (John Wiley & Sons, 2013-08-02)Over the period 2003–2011, the Gravity Recovery and Climate Experiment (GRACE) satellite pair revealed a remarkable variability in mass-induced sea surface height (MSSH) in the northwestern North Pacific. A significant ...
Coupling instrumental and geological records of sea-level change : evidence from southern New England of an increase in the rate of sea-level rise in the late 19th century Donnelly, Jeffrey P.; Cleary, Peter; Newby, Paige E.; Ettinger, Robert (American Geophysical Union, 2004-03-11)We construct a high-resolution relative sea-level record for the past 700 years by dating basal salt-marsh peat samples above a glacial erratic in an eastern Connecticut salt marsh, to test whether or not the apparent ...
PSP toxin levels and plankton community composition and abundance in size-fractionated vertical profiles during spring/summer blooms of the toxic dinoflagellate Alexandrium fundyense in the Gulf of Maine and on Georges Bank, 2007, 2008, and 2010 : 1. Toxin levels Deeds, Jonathan R.; Petitpas, Christian M.; Shue, Vangie; White, Kevin D.; Keafer, Bruce A.; McGillicuddy, Dennis J.; Milligan, Peter J.; Anderson, Donald M.; Turner, Jefferson T. (Elsevier, 2013-04-12)As part of the NOAA ECOHAB funded Gulf of Maine Toxicity (GOMTOX)1 project, we determined Alexandrium fundyense abundance, paralytic shellfish poisoning (PSP) toxin composition, and concentration in quantitatively-sampled ...