Wind-Forced Equatorial Waves in the Atlantic Ocean.
Abstract
During the GARP Atlantic Tropical Experiment (GATE), north-south fluctuations in the equatorial current system were observed. Observations of current profiles during Phase II suggest that the fluctuations had a period of about 16 days and were propagating westward with a phase speed of 130 to 190 cm/sec. Evidence of fluctuations in the tradewinds at similar frequencies was also found. Analysis of profiling current meter (PCM) data reveals that latitudinal shear in the zonal equatorial currents is important, and that meridional and vertical motions are highly time-dependent and have small means. Theoretical analysis of a linear, two-layer system shows that the characteristics of the observed fluctuations are consistent with the theory of linear, equatorially trapped waves, particularly the Yanai wave. Numerical integration of equations of this system shows that oscillations such as those observed may be a resonant response to an impulsive, cross-equatorial forcing in the upper layer. The presence of a mean zonal flow with shear modifies but does not drastically alter, the results. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- May 01, 1977
- Accession Number
- ADA040829
Entities
People
- Zachariah R. Hallock
Organizations
- Rosenstiel School of Marine, Atmospheric, and Earth Science