Analyses of surface meteorological fields over the northwestern Gulf of Mexico and wind effects on the circulation over the LATEX shelf

There were three objectives in this research. The first was to formulate surface meteorological fields from in situ, time series of observation over the Texas-Louisiana continental shelf for a period from April 1992 to November 1994. The second objective was to compare resulting wind fields (LATEX fields) with simultaneous wind fields produced from NMC weather prediction model and observed by ERS-1 satellite scatterometer. The third objective was to examine the response of nearshore currents to alongshore winds over the shelf region and further determine response time and spatial extent of response.; The results of wind comparisons showed that the NMC winds were larger (about 2 m/s) than the LATEX winds and had 10 degree bias in direction. Large differences between the two wind sets occurred in the central area of the shelf. Fronts in the NMC wind fields usually moved faster than in the LATEX fields. The LATEX winds were only slightly larger than ERS-1 winds (less than 2 m/s) and there was no bias for wind directions between the two data sets. The comparisons indicated that the LATEX wind fields provided realistic and detailed surface winds that are good for the study of mesoscale processes over the Texas-Louisiana continental shelf.; Monthly and seasonal mean surface meteorological fields showed that there are two principal patterns for surface atmosphere over the shelf region: summer and non-summer. From June to August, surface atmosphere is relatively stable and alongshore wind component is upcoast (from Brownsville to Mississippi Delta). In the remaining months, surface atmosphere has great variability and alongshore wind component is generally downcoast.; The response of nearshore currents to alongshore winds was examined at low frequency and short term temporal scales. Results showed that alongshore wind component is the principal force for alongshore currents over the inner shelf. Large crosscorrelation (0.5-0.6) between alongshore current and wind components and short response time (4-5 hours) occurred over the shelf off the south Texas coast. Crosscorrelation values decreased offshore and response time increased upcoast to approximate 10 hours off the Mississippi Delta. The area of significant correlation between alongshore wind and current components was limited to inshore of the 200-m isobath off Brownsville but only out to the 20-m isobath off the Mississippi Delta.