edu.ucar.opensky::articles:24140 UCAR/NCAR - Library OpenSky Support PO Box 3000 Boulder CO 80307-3000 opensky@ucar.edu http://opensky.ucar.edu/ homepage pointOfContact 2025-12-25T06:35:00.657643 ISO 19115-2 Geographic Information - Metadata - Part 2: Extensions for Imagery and Gridded Data ISO 19115-2:2009(E) https://n2t.org/ark:/85065/d77084s9 https://doi.org/10.5281/zenodo.4506273 https Related Dataset #1 Supplementary Material (Simulation code and data) for the paper Dang et al., gmd, Azimuthal averaging–reconstruction filtering techniques for finite-difference general circulation models in spherical geometry,2021 https://doi.org/10.5281/zenodo.4506230 https Related Software #1 dangt-ustc/TIEGCM2.1: TIEGCM 2.1 Azimuthal averaging -- Reconstruction filtering techniques for finite-difference general circulation models in spherical geometry 2021-02-10T00:00:00Z publication https://n2t.org/ark:/85065/d77084s9 https://doi.org/10.5194/gmd-14-859-2021 Dang, Tong author Zhang, Binzheng author Lei, J. author Wang, Wenbin author Burns, Alan author Liu, Hanli author Pham, Kevin author Sorathia, K. A. author UCAR/NCAR - Library publisher When solving hydrodynamic equations in spherical or cylindrical geometry using explicit finite-difference schemes, a major difficulty is that the time step is greatly restricted by the clustering of azimuthal cells near the pole due to the Courant-Friedrichs-Lewy condition. This paper adapts the azimuthal averaging-reconstruction (ring average) technique to finite-difference schemes in order to mitigate the time step constraint in spherical and cylindrical coordinates. The finite-difference ring average technique averages physical quantities based on an effective grid and then reconstructs the solution back to the original grid in a piecewise, monotonic way. The algorithm is implemented in a community upper-atmospheric model, the Thermosphere-Ionosphere Electrodynamics General Circulation Model (TIEGCM), with a horizontal resolution up to 0.625 degrees x 0.625 degrees in geographic longitude-latitude coordinates, which enables the capability of resolving critical mesoscale structures within the TIEGCM. Numerical experiments have shown that the ring average technique introduces minimal artifacts in the polar region of general circulation model (GCM) solutions, which is a significant improvement compared to commonly used low-pass filtering techniques such as the fast Fourier transform method. Since the finite-difference adaption of the ring average technique is a post-solver type of algorithm, which requires no changes to the original computational grid and numerical algorithms, it has also been implemented in much more complicated models with extended physical-chemical modules such as the Coupled Magnetosphere-Ionosphere-Thermosphere (CMIT) model and the Whole Atmosphere Community Climate Model with thermosphere and ionosphere eXtension (WACCM-X). The implementation of ring average techniques in both models enables CMIT and WACCM-X to perform global simulations with a much higher resolution than that used in the community versions. The new technique is not only a significant improvement in space weather modeling capability, but it can also be adapted to more general finite-difference solvers for hyperbolic equations in spherical and polar geometries. UCAR/NCAR - Library OpenSky Support PO Box 3000 Boulder CO 80307-3000 opensky@ucar.edu http://opensky.ucar.edu/ homepage pointOfContact PDF Text theme Resource Type 2016-01-01T00:00:00Z publication Copyright author(s). This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License. None eng geoscientificInformation