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Title

Statistical Analysis of Eight Years of Ocean Color and SST Data in the Tropical Pacific

Author

Peter Gaube, Nova Southeastern University

Defense Date

5-23-2007

Document Type

Thesis - NSU Access Only

Department

Oceanographic Center

First Advisor

Sean Kennan

Second Advisor

Alexander Soloviev

Third Advisor

Alexander Yankovsky

Abstract

Eight years of contemporaneous SST and ocean color data were statistically compared and contrasted to quantify their variations over a range of time and space scales. While it is generally accepted that chlorophyll concentrations (a proxy for primary production) on the equator are directly forced by upwelling, it is not clear that a simple correlation between SST and ocean color exists outside the equatorial wave guide or how it may depend on scale. The Tropical Rainfall Measuring Missions microwave imager (TMI) and Sea View Wide Field of View sensor (SeaWiFS) sensors have been in operation simultaneously for a period of nine years. Thus, the resolution of eight full seasonal cycles, including several ENSO cycles, suggest that significant results can be obtained by statistically analyzing the correlations between these satellite observed data sets. The statistical techniques include simple correlations and empirical orthogonal functions. Of particular interest are the possible influences which tropical instability induced circulations have on the marine ecosystem and ocean color. While results presented in this study are consistent with the paradigm that equatorial upwelling causes high productivity in the cold tongue, the overall relationship between SST and CHL (chlorophyll-a) is complex, depending on both time and space scale.

The dominant modes of temporal variability in both data set are shown to vary on a seasonal cycle, with an inter-annual component. In addition negative correlation is found in regions where fronts in both SST and ocean color are disturbed by the passing of tropical instabilities and mesoscale eddies. Several zones are identified where eddy forcing clearly indicates a relationship between enhanced primary production and the influx of relatively cold waters. While it is likely that the coastal regions are dominated by upwelling processes, the previously established dynamics of tropical instabilities lead us to propose that horizontal advection within instability vortices is the dominant process leading to enhanced primary production along the equatorial fronts.

NSUWorks Citation

Peter Gaube. 2007. Statistical Analysis of Eight Years of Ocean Color and SST Data in the Tropical Pacific. Master's thesis. Nova Southeastern University. Retrieved from NSUWorks, Oceanographic Center. (265)
https://nsuworks.nova.edu/occ_stuetd/265.