Two-Dimensional Evaluation of ATHAM-Fluidity, a Nonhydrostatic Atmospheric Model Using Mixed Continuous/Discontinuous Finite Elements and Anisotropic Grid Optimization
File(s)
Published version
Author(s)
Savre, J
Percival, J
Herzog, M
Pain, C
Type
Journal Article
Abstract
This paper presents the first attempt to apply the compressible nonhydrostatic ATHAM-Fluidity solver to a series of idealized atmospheric test cases. ATHAM-Fluidity uses a hybrid finite-element discretization where pressure is solved on a continuous 2nd order grid while momentum and scalars are computed on a 1st order discontinuous grid (also known as 1DG–2). ATHAM-Fluidity operates on two- and three-dimensional unstructured meshes, using triangular or tetrahedral elements respectively, with the possibility to employ an anisotropic mesh optimization algorithm for automatic grid refinement and coarsening during run-time. The solver is evaluated using two-dimensional only dry idealized test cases covering a wide range of atmospheric applications. The first three cases, representative of atmospheric convection, reveal the ability of ATHAM-Fluidity to accurately simulate the evolution of large scale flow features in neutral atmospheres at rest. Grid convergence without adaptivity as well as the performances of the Hermite-WENO slope limiter are discussed. These cases are also used to test the grid optimisation algorithm implemented in ATHAM-Fluidity. Adaptivity can result in up to a six-fold decrease in computational time and a five-fold decrease in total element number for the same finest resolution. However, substantial discrepancies are found between the uniform and adapted grid results, thus suggesting the necessity to improve the reliability of the approach. In the last three cases, corresponding to atmospheric gravity waves with and without orography, the model ability to capture the amplitude and propagation of weak stationary waves is demonstrated. This work constitutes the first step towards the development of a new comprehensive limited area atmospheric model.
Date Issued
2016-06-13
Date Acceptance
2016-06-01
Citation
Monthly Weather Review, 2016, 144 (11), pp.4349-4372
ISSN
0027-0644
Publisher
American Meteorological Society
Start Page
4349
End Page
4372
Journal / Book Title
Monthly Weather Review
Volume
144
Issue
11
Copyright Statement
© 2016 American Meteorological Society
Subjects
Meteorology & Atmospheric Sciences
0401 Atmospheric Sciences
Publication Status
Published