Determining Undersampled Coastal Tidal Harmonics Using Regularized Least Squares

Abstract Satellite altimetry, which measures water level with global coverage and high resolution, provides an unprecedented opportunity for a wide refined understanding of the changing tides in coastal area. But its sampling frequency is too low to satisfy Nyquist requirement few data points per year are available recognize sufficient number tidal constituents capture trend changes on yearly basis. To address these issues, novel regularized least‐square approach developed relax interval limit range 9–11 days, reaching revisit time existing satellites. In this method, prior information regional amplitudes used support least square analysis obtain elevation series different lengths intervals. Synthetic experiments performed Delaware Bay Galveston showed that proposed method can determine accuracy be extended application major altimetry The algorithm was further validated using mission, Jason‐3, show applicability irregular noisy data. new could help identify sea‐level rise anthropogenic activities areas, informing flooding risk assessment ecosystem health analysis.