Zarate Jimenez, Luz Areli (2018-08). Resolving the Small-Scale Spatial Current Structure of the Upper Texas Coast. Master's Thesis.
Understanding the circulation of the oceanic currents provides information to mitigate the impact of hazards and to respond timely in the case of an emergency by making critical decisions promptly. In early 2016, the Geochemical and Environmental Research Group (GERG) started the installation of a High-Frequency (HF) radar network in Texas to improve the spatial resolution of the in situ oceanic measurements presently collected by the Texas Automated Buoy System (TABS). Both systems, HF radar and TABS, are operated and maintained by GERG. The present research thesis analyzes 2 out of the 3 HF radar sites (Rollover and Surfside), and 4 out of the 9 TABS buoys (B, F, W, and R), for a period of ~17.5 months, from June of 2016-November of 2017. During this analysis the summer reversal for 2016 and 2017 is captured, noting that it occurred in mid-June - mid-August, and a few days earlier in 2016. Based on correlation coefficients, SSDE performs better than RLVR, particularly when compared to buoy F. Bathymetry and salinity impact the performance of the HF radar, and there is potential attenuation on RLVR by ship navigation. Variance ellipses tend to follow the 50-m isobath, in agreement to Nowlin et al. (2005) inshore-offshore isobath limit definition, with a dominant NE-SW orientation of the major axis, with a higher variance associated with regions of less data density and steeper gradients in the bathymetry. Power spectra showed an increase in the energy in the diurnal and semidiurnal frequency, with a predominant clockwise rotation as indicated by rotary spectra. Coherence analysis showed coherence >95% confidence interval near the inertial band is indicative of rotation due to inertial response. The main tidal constituents found in this thesis are O1, P1, K1, M2, and S2. Wavelet analysis also showed an increase in the diurnal and semidiurnal period, as well as an increase in the energy in the weather band (2-15 days), and high power content on the diurnal band during the summer for the detided record, suggesting that this is due to sea-breeze effects and inertial motions, given that the local inertial period is 24.78 hrs.