SEMINARS
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Fall 2005
STATISTICS
COLLOQUIUM
Friday, October 21, 2005
2:30-3:00—Refreshments
3:00-4:00—Talk
Yost Hall, Room 327
Alexandra Piryatinska
California Institute of Technology (JPL)
Statistical Analysis of the Wave Front Observed in the Ocean Altimeter and ECCO Model Data
We consider large scale oceanic motion in the absence of spatial homogeneity in the meridional direction. The statistical methods for the estimation of the wave front were developed. This approach is illustrated on the example of Tropical Pacific between 20S and 20 0 N. These results are then compared with similar results derived from ECCO oceanic data modeling methodology.
Our special treatment permits quantitative characterization of latitudinally alternating, zonally elongated features of the sea surface height (SSH) field. These features are due primarily to baroclinic quasi-geostrophic motions such as highly irregular Rossby waves forming a background of soliton turbulence. Their wavefronts are analyzed for the first time. To this end, we use the phase shift information derived through a cross-spectral analysis of SSH ariations along pairs of neighboring latitudes (1 deg apart). Spectral and cross-spectral properties are estimated separately for several relatively narrow bands of timescales (from semi- to multi-annual) which are clearly distinguishable in the frequency spectra of both westward and eastward motions. Of particular interest are our intercomparisons of altimeter- and model-based spectral composition of equatorial dynamics, of the position of vorticity fronts (which is a by-product of the present analysis), and of the parameters of equatorial solitons.
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