IX. Conclusion VIII. Discussion Currents: A geostrophic balance between Florida Current transport and coastal sea levels at 4-8 day periods (Fig 2). Depth-averaged currents were consistent between all locations (Fig 3), with along- shelf currents dominating. Semidiurnal signal in currents and sea level, while diurnal signal only significant in sea level and backscatter (Fig 4). Subtidal Inner Shelf Dynamics At Cape-Associated Shoals Sabrina Marie Parra 1*, Arnoldo Valle-Levinson 2, Peter Adams 3, Juan Felipe Paniagua 3 1 American Society of Engineering Education Research Associate at Naval Research Laboratory, Stennis Space Center, MS; 2 Department of Civil and Coastal Engineering, University of Florida, Gainesville, FL, USA; 3 Department of Geology, University of Florida, Gainesville, FL, USA. Inner shelf subtidal currents at Cape Canaveral were mostly dominated by the along-shelf component, which was controlled by the geostrophic balance between the Florida Current and coastal sea levels. The dynamic inner-shelf is mainly affected by wind and surface gravity waves with secondary forcing from offshore currents (Lentz and Fewings 2012). The influence on subtidal currents by winds, waves and the Florida Current were investigated within the inner-shelf environment adjacent to Cape Canaveral, Florida. The study focused on two cape-associated shoals for a northern (False Cape) and southern promontory (Cape Canaveral proper). I. Introduction IV. Parameters VI. Complex Empirical Orthogonal Functions II. Data Acoustic Doppler current profilers (ADCPs) were moored on either side (seaward and landward) of the shoals for 52 days. The following parameters were filtered to remove tides: ADCP depth, and depth-averaged currents and backscatter NOAA buoy wind and wave parameters Florida Current (FC) transport between Florida and Bahamas (Fig 1) Sea level at Trident Pier off Cape Canaveral Fig. 1: Bathymetric map of Cape Canaveral with the four moorings (circles) and National Oceanographic and Atmospheric Administration (NOAA) buoy #41009 (diamond). The black box denotes the location of the NOAA Trident Pier tidal gauge and Florida Current (FC) measurements were measured at the green line in the inset US map. Fig. 3: Subtidal parameters at Cape Canaveral. All vectors point in the direction of propagation. Currents and backscatter anomaly are depth averaged. Fig. 4: Spectral analysis of depth-averaged currents, water levels and depth-averaged backscatter from each mooring. Black lines represent the 95% confidence interval. Fig. 2: Geostrophic balance between coastal sea level and Florida Current transport. A) Subtidal sea level at Trident Pier (blue) and Florida Current transport (black). B) Wavelet coherence between Trident Pier sea level and Florida Current transport. Contours show high (red) and low (blue) coherences. Areas enclosed by black contours represent coherence >95% confidence limit. Bottom corner shaded edges are the cone of influence where values are less reliable. Coherence phase angles are represented by the vectors (Torrence and Compo 1998; Grinsted et al. 2004). Fig 5. CEOF of currents. A) CEOF mode 1 time series for the cross-shelf (east, blue) and along- shelf (west, green) velocity components. Mode 1 vertical profiles for the B) cross-shelf and C) along-shelf velocity components for each location. Fig 6. Wavelet coherences between CEOF mode 1 of the east (first column) and north (second column) currents and different forcing parameters. V. Spectral Analysis A B C Cross-shelf, U Along-shelf, V Along-shelf Cross- shelf XI. References Bjornsson, H. and S. Venegas (1997), A manual for EOF and SVD analyses of climatic data, CCGCR Report, 97(1). Grinsted, A., J. C. Moore, and S. Jevrejeva (2004), Application of the cross wavelet transform and wavelet coherence to geophysical time series, Nonlinear processes in geophysics, 11(5/6), Lentz, S. J. and M. R. Fewings (2012), The wind-and wave- driven inner-shelf circulation, Annual Review of Marine Science, 4, , doi: /annurev-marine Torrence, C. and G. P. Compo (1998), A practical guide to wavelet analysis, Bull. Am. Meteorol. Soc., 79(1), III. Geostrophic Balance: Florida Current VII. Wavelet Coherence Analysis Complex Empirical Orthogonal Function (CEOF), Fig 5: CEOF shows dominant spatial and temporal structures (Bjornsson and Venegas 1997). The subtidal CEOF mode 1 accounted for 92% of the variance, with vertical profiles showing unidirectional flow throughout (B,C). Along-shelf current vertical structuresa had same direction and magnitude, while cross- shelf currents varried with Chester weaker than Canaveral. Wavelet Coherence: EOF 1 vs Forcings (Fig 6) The both velocity components were driven by fortnightly north winds Water levels were the primary modulators of the along-shelf current at ~7 day periods, which was influenced by the Florida Current transport. X. Acknowledgements This work was supported by a grant from the Bureau of Ocean Energy Management. Special thanks to Viktor Adams, Michael Dickson, Patrick McGovern, Lauren Ross, Jackie Branyon, Mohammad Alkaldi, Ahmad Yousif and anyone that helped with fieldwork. The Florida Current Transport cable and section data are made freely available from the Atlantic Oceanographic and Meteorological Laboratory ( and are funded by the Department of Commerce NOAA Climate Program Office-Climate Observation Division. Thanks to Aslak Grinsted, John Moore and Svetlana Jevrejeva for allowing the use of their MATLAB wavelet package (noc.ac.uk/using-science/crosswavelet-wavelet-coherence). Cross-shelf, U Along-shelf, V Trident Pier FC