Statistical representation of equatorial waves and tropical instability waves in the Pacific Ocean

2009 ◽  
Vol 94 (1) ◽  
pp. 37-44 ◽  
Author(s):  
Toshiaki Shinoda ◽  
George N. Kiladis ◽  
Paul E. Roundy
Keyword(s):  
Pacific Ocean ◽  
Equatorial Waves ◽  
Instability Waves ◽  
Tropical Instability Waves ◽  
Statistical Representation ◽  
The Pacific ◽  
The Pacific Ocean

scholarly journals Barotropic Rossby Waves Radiating from Tropical Instability Waves in the Pacific Ocean

2011 ◽  
Vol 41 (6) ◽  
pp. 1160-1181 ◽  
Author(s):  
J. Thomas Farrar
Keyword(s):  
Dispersion Relation ◽  
Pacific Ocean ◽  
Sea Level ◽  
Rossby Waves ◽  
North Pacific Subtropical Gyre ◽  
Sea Level Variability ◽  
Instability Waves ◽  
Tropical Instability Waves ◽  
The Pacific ◽  
The Pacific Ocean

Abstract Tropical instability waves are triggered by instabilities of the equatorial current systems, and their sea level signal, with peak amplitude near 5°N, is one of the most prominent features of the dynamic topography of the tropics. Cross-spectral analysis of satellite altimetry observations shows that there is sea level variability in the Pacific Ocean as far north as Hawaii (i.e., 20°N) that is coherent with the sea level variability near 5°N associated with tropical instability waves. Within the uncertainty of the analysis, this off-equatorial variability obeys the dispersion relation for nondivergent, barotropic Rossby waves over a fairly broad range of periods (26–38 days) and zonal wavelengths (9°–23° of longitude) that are associated with tropical instability waves. The dispersion relation and observed wave properties further suggest that the waves are carrying energy away from the instabilities toward the North Pacific subtropical gyre, which, together with the observed coherence of the sea level signal of the barotropic waves with that of the tropical instability waves, suggests that the barotropic Rossby waves are being radiated from the tropical instability waves. The poleward transport of kinetic energy and westward momentum by these barotropic Rossby waves may influence the circulation in the subtropics.

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