Drivers of Interannual Sea Level Variability on the Northwestern European Shelf

Drivers of Interannual Sea Level Variability on the Northwestern European Shelf

Hermans, T.H.J. (TU Delft Physical and Space Geodesy; Universiteit Utrecht)
Le Bars, Dewi (Royal Netherlands Meteorological Institute (KNMI))
Katsman, C.A. (TU Delft Environmental Fluid Mechanics)
Machado Lima de Camargo, C. (TU Delft Physical and Space Geodesy; Universiteit Utrecht)
Gerkema, Theo (Universiteit Utrecht)
Calafat, Francisco M. (National Oceanography Centre)
Tinker, Jonathan (Met Office Hadley Centre)
Slangen, Aimée B. A. (Universiteit Utrecht)

2020

Sea level on the northwestern European shelf (NWES) varies substantially from year to year. Removing explained parts of interannual sea level variability from observations helps to improve estimates of long-term sea level trends. To this end, the contributions of different drivers to interannual sea level variability need to be understood and quantified. We quantified these contributions for the entire NWES by performing sensitivity experiments with a high-resolution configuration of the Regional Ocean Modeling System (ROMS). The lateral and atmospheric boundary conditions were derived from reanalyses. We compared our model results with satellite altimetry data and used our sensitivity experiments to show that nonlinear feedbacks cause only minor interannual sea level variability on the shelf. This indicates that our experiments can be used to separate the effects of different drivers. We find that wind dominates the variability of annual mean sea level in the southern and eastern North Sea (up to 4.7-cm standard deviation), whereas the inverse barometer effect dominates elsewhere on the NWES (up to 1.7-cm standard deviation). In contrast, forcing at the lateral ocean boundaries results in small and coherent variability on the shelf (0.5-cm standard deviation). Variability driven by buoyancy fluxes ranges from 0.5- to 1.3-cm standard deviation. The results of our sensitivity experiments explain the (anti)correlation between interannual sea level variability at different locations on the NWES and can be used to estimate sea level rise from observations in this region with higher accuracy.

ROMS
interannual sea level variability
northwestern European shelf
regional ocean model
satellite altimetry era
sensitivity experiments

http://resolver.tudelft.nl/uuid:7710714d-86b4-4261-bf5e-9726a9a06daa

https://doi.org/10.1029/2020JC016325

2169-9275

Journal Of Geophysical Research-Oceans, 125 (10), 1-18

Institutional Repository

journal article

© 2020 T.H.J. Hermans, Dewi Le Bars, C.A. Katsman, C. Machado Lima de Camargo, Theo Gerkema, Francisco M. Calafat, Jonathan Tinker, Aimée B. A. Slangen