Versatile Harmonic Tidal Analysis: Improvements and Applications

Abstract

New computer software that permits more versatility in the harmonic analysis of tidal time series is described and tested. Specific improvements to traditional methods include the analysis of randomly sampled and/or multiyear data; more accurate nodal correction, inference, and astronomical argument adjustments through direct incorporation in the least squares matrix; multiconstituent inferences from a single reference constituent; correlation matrices and error estimates that facilitate decisions on the selection of constituents for the analysis; and a single program that analyzes one- or two-dimensional time series. This new methodology is evaluated through comparisons with results from old techniques and then applied to two problems that could not have been accurately solved with older software. They are (i) the analysis of ocean station temperature time series spanning 25 yr, and (ii) the analysis of satellite altimetry from a ground track whose proximity to land has led to significant data dropout. This new software is free as part of the Institute of Ocean Sciences (IOS) Tidal Package and can be downloaded, along with sample input data and an explanatory readme file.

LoadDef: A Python‐Based Toolkit to Model Elastic Deformation Caused by Surface Mass Loading on Spherically Symmetric Bodies

“…Gravitational fields can elicit both a direct response, known as body tides, and an indirect response due to surface loading, known as load tides (e.g., Agnew, 2015;Melchior, 1983). Furthermore, since the tidal potential may be decomposed into a series of harmonics, tidal deformations may be extracted from geodetic time-series data using standard curve-fitting methods (e.g., Foreman et al, 2009;. Furthermore, since the tidal potential may be decomposed into a series of harmonics, tidal deformations may be extracted from geodetic time-series data using standard curve-fitting methods (e.g., Foreman et al, 2009;.…”

Tidal and residual currents in the Qiongzhou Strait estimated from shipboard ADCP data using a modified tidal harmonic analysis method

“…First, we obtained a 364.4 day long hourly tidal level time series for 1997 at Haikou tidal gauge station near our observation site from Hawaii sea level center (these is not record for 2013). The harmonic analysis using conventional method with a nodal tide correction [Foreman et al, 2009] ) and Z 0 . Then we perform conventional harmonics analyses with different inferences, using T_Tide, UTide Matlab software and our modified tidal harmonics analyses method, respectively.…”

Sea Level Forecasts Aggregated from Established Operational Systems

“…Many variations exist for implementing this general approach (e.g., [20][21][22][23]). Useful sea level predictions can thereby be produced many years into the future.…”