Inverted echo sounder observations of variability in the eastern equatorial Pacific during the 1982-1983 El Niño
Document Type
Article
Date of Original Version
1-1-1987
Abstract
Meridional and zonal baroclinic variability during the 1982-1983 El Niño was investigated in a ∼ 1000-km region around the Galapagos Islands with an array of three inverted echo sounders. The resulting dynamic height time series show two principal maxima separated by several months, in good agreement with the available CTD observations of this El Niño. Autospectra, dispersion characteristics and symmetry properties reveal that the first baroclinic mode wave field contains five regimes: (1) at long time scales (T ∼ 114 days), westward-propagating Rossby waves; (2) in the 38- to 16-day band, a barotropic instability mode with westward phase and group velocity; (3) near 12 days, eastward-propagating Kelvin waves; (4) from 10 to 4 days, clearly defined eastward-propagating Rossby-gravity waves; and (5) in the 6- to 2-day band, inertia-gravity waves of locally resonant second and possibly higher meridional modes. Strong 3.3-day peaks at two sites are not locally resonant inertia-gravity waves and instead are likely to be basin-wide third meridional mode inertia-gravity waves generated in the western or central Pacific. © 1987.
Publication Title, e.g., Journal
Deep Sea Research Part A, Oceanographic Research Papers
Volume
34
Issue
3
Citation/Publisher Attribution
Chiswell, Stephen M., D. R. Watts, and Mark Wimbush. "Inverted echo sounder observations of variability in the eastern equatorial Pacific during the 1982-1983 El Niño." Deep Sea Research Part A, Oceanographic Research Papers 34, 3 (1987). doi: 10.1016/0198-0149(87)90140-3.