The impact of the dynamic sea surface topography on the quasi-geoid in shallow coastal waters

摘要: In this study, we examine the impact of instantaneous dynamic sea surface topography (DT) corrections to be applied altimeter-derived slopes on quasi-geoid in shallow and coastal waters North Sea. particular, investigate added value DT obtained from a shallow-water hydrodynamic model. These comprise contributions ocean tides, wind- pressure-driven (surge), density-driven (baroclinic) water-level variations including interactions between them. As reference, used tidal derived global tide model GOT4.7, surge MOG2D model, for time-averaged baroclinic contribution computed as differences DTU10 mean EGG08 quasi-geoid. From spectral analysis, found that parts mainly contribute improvements signal-to-noise ratio (SNR) at longer wavelengths down \(100{-}200~\hbox {km}\) increase towards southern We also provides better compared GOT4.7 which are most pronounced Sea affect almost entire spectrum. Very small (mostly below \({\pm } 2~\hbox {cm}\)) observed solutions using different sets corrections. showed variance component estimation too optimistic factors shipboard data set relative slopes. Hence, limited is due fact hardly estimated if gravity included. When computing without data, less accurate or incomplete may cause errors with systematic spatial patterns. patterns disappear reduced significantly when provided by The main contributor improvement correction Seen models over last two decades, expect near future perform well dedicated regional such DCSM. Critical issue is, however, access high-quality local bathymetric data.