Global Barotropic Tide Modeling Using Inline Self-Attraction and Loading in MPAS-Ocean

Type Article
Date 2022-11
Language English
Author(s) Barton Kristin N.1, Pal Nairita2, Brus Steven R.3, Petersen Mark R.2, Arbic Brian K.4, Engwirda DarrenORCID2, Roberts Andrew F.2, Westerink Joannes J.5, Wirasaet Damrongsak5, Schindelegger MichaelORCID6
Affiliation(s) 1 : Department of Physics, University of Michigan, Ann Arbor, MI, USA
2 : Los Alamos National Laboratory, Los Alamos, NM, USA
3 : Mathematics and Computer Science Division, Argonne National Laboratory, Lemont, IL, USA
4 : Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI, USA
5 : Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, Notre Dame, IN, USA
6 : Institute of Geodesy and Geoinformation, University of Bonn, Bonn, Germany
Source Journal Of Advances In Modeling Earth Systems (1942-2466) (Amer Geophysical Union), 2022-11 , Vol. 14 , N. 11 , P. e2022MS003207 (19p.)
DOI 10.1029/2022MS003207
WOS© Times Cited 5
Keyword(s) surface tides, self-attraction and loading, numerical ocean modeling, MPAS-Ocean, barotropic tides, E3SM
Abstract

We examine ocean tides in the barotropic version of the Model for Prediction Across Scales (MPAS-Ocean), the ocean component of the Department of Energy Earth system model. We focus on four factors that affect tidal accuracy: self-attraction and loading (SAL), model resolution, details of the underlying bathymetry, and parameterized topographic wave drag. The SAL term accounts for the tidal loading of Earth's crust and the self-gravitation of the ocean and the load-deformed Earth. A common method for calculating SAL is to decompose mass anomalies into their spherical harmonic constituents. Here, we compare a scalar SAL approximation versus an inline SAL using a fast spherical harmonic transform package. Wave drag accounts for energy lost by breaking internal tides that are produced by barotropic tidal flow over topographic features. We compare a series of successively finer quasi-uniform resolution meshes (62.9, 31.5, 15.7, and 7.87 km) to a variable resolution (45 to 5 km) configuration. We ran MPAS-Ocean in a single-layer barotropic mode forced by five tidal constituents. The 45 to 5 km variable resolution mesh obtained the best total root-mean-square error (5.4 cm) for the deep ocean (> $ > $1,000 m) M2 ${\mathrm{M}}_{2}$ tide compared to TPXO8 and ran twice as fast as the quasi-uniform 8 km mesh, which had an error of 5.8 cm. This error is comparable to those found in other forward (non-assimilative) ocean tide models. In future work, we plan to use MPAS-Ocean to study tidal interactions with other Earth system components, and the tidal response to climate change.

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Barton Kristin N., Pal Nairita, Brus Steven R., Petersen Mark R., Arbic Brian K., Engwirda Darren, Roberts Andrew F., Westerink Joannes J., Wirasaet Damrongsak, Schindelegger Michael (2022). Global Barotropic Tide Modeling Using Inline Self-Attraction and Loading in MPAS-Ocean. Journal Of Advances In Modeling Earth Systems, 14(11), e2022MS003207 (19p.). Publisher's official version : https://doi.org/10.1029/2022MS003207 , Open Access version : https://archimer.ifremer.fr/doc/00838/94987/