Date of Award

Winter 1999

Document Type


Degree Name

Doctor of Philosophy (PhD)


Ocean & Earth Sciences

Committee Director

A. D. Kirwan, Jr.

Committee Director

C. E. Grosch

Committee Member

J. A. Adam

Committee Member

J. M. Harding

Committee Member

B. L. Lipphardt, Jr.


Rapid environmental assessment is conducted using disparate data sources in the northwestern Gulf of Mexico. An overview of significant physical features in the Gulf highlights the complexities of the large and meso-scale circulations. Spectral analysis of high resolution current meter and drifter data reveals the significant forcing features detectable by readily available observing techniques. These observations are combined with boundary data extracted from the U.S. Navy's Modular Ocean Data Assimilation System (MODAS) through Normal Mode Analysis (NMA). The NMA blending process is described, and surface maps of velocity and convergence are produced. Using statistical and qualitative techniques, the NMA generated “nowcasts” are analyzed to determine the significant modes applicable to varying oceanographic situations. Fundamental guidance for choosing the number and type of modes in an REA scenario are noted. The NMA method proves to be a useful tool in constructing analytic surface maps when the component modes are wisely chosen.


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