MPAS‐Ocean Simulation Quality for Variable‐Resolution North American Coastal Meshes

Abstract Climate model components utilizing unstructured meshes enable variable resolution, regionally enhanced simulations within global domains. Here we investigate the relationship between mesh quality and simulation statistics using the JIGSAW unstructured meshing library and the Model for Predi...

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Bibliographic Details
Published in:Journal of Advances in Modeling Earth Systems
Main Authors: Kristin E. Hoch, Mark R. Petersen, Steven R. Brus, Darren Engwirda, Andrew F. Roberts, Kevin L. Rosa, Phillip J. Wolfram
Format: Article in Journal/Newspaper
Language:English
Published: American Geophysical Union (AGU) 2020
Subjects:
ocean modeling
mesh
variable resolution
MPAS‐Ocean
mesh quality
Gulf Stream
Physical geography
GB3-5030
Oceanography
GC1-1581
Southern Ocean
Online Access:https://doi.org/10.1029/2019MS001848
https://doaj.org/article/36949e2fc7964b569c513181271103a1
Description
Summary:Abstract Climate model components utilizing unstructured meshes enable variable resolution, regionally enhanced simulations within global domains. Here we investigate the relationship between mesh quality and simulation statistics using the JIGSAW unstructured meshing library and the Model for Prediction Across Scales‐Ocean (MPAS‐Ocean) with a focus on Gulf Stream dynamics. In the base configuration, the refined region employs 8 km cells that extend 400 km from the coast of North America. This coastal‐refined region is embedded within a low‐resolution global domain, with cell size varying latitudinally between 30 and 60 km. The resolution transition region between the refined region and background mesh is 600 km wide. Three sensitivity tests are conducted: (a) The quality of meshes is intentionally degraded so that horizontal cells are progressively more distorted; (b) the transition region from high to low resolution is steepened; and (c) resolution of the coastal refinement region is varied from 30 to 8 km. Overall, the ocean simulations are shown to be robust to mesh resolution and quality alterations. Meshes that are substantially degraded still produce realistic currents, with Southern Ocean transports within 0.4% and Gulf Stream transports within 12% of high‐quality mesh results. The narrowest transition case of 100 km did not produce any spurious effects. Refined regions with high‐resolution produce eddy kinetic energy and sea surface height variability that are similar to the high‐resolution reference simulation. These results provide heuristics for the design criteria of variable‐resolution climate model domains.

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