Analysis of Sebastian Inlet, FL, Morphologic Changes Using Complex Empirical Orthogonal Functions (CEOF)

Complex empirical orthogonal function (CEOF) analysis is applied to investigate the medium-term morphologic evolution of the ebb shoal at Sebastian inlet, using a high resolution decadal dataset of hydrographic surveys. Results indicate that most of the variance (98.2%) is found in the first complex function (SM-1) interpreted as the average bathymetry, showing no significant time-dependent fluctuation. The second function (SM-2) accounts for 0.8% of the total variance and is dominated by a cross-shore transfer between the shoreward and leeward flanks of the shoal, as well as deposition from the ebb-jet and natural bypassing around the shoal. The temporal dependence (TM-2) showed large random changes that may correspond to bypassing activities in the inlet vicinity. The CEOF technique is successful in reproducing propagating sedimentation patterns not recognized by regular EOF, such as bypassing around the leeward flanks of the shoal, and cross-shore transfer around the terminal lobe and availability for bypassing.