Enforcing conservation of axial angular momentum in the atmospheric general circulation model CAM6
<p>Numerical general circulation models of the atmosphere are generally required to conserve mass and energy for their application to climate studies. Here we draw attention to another conserved global integral, viz. the component of angular momentum (AM) along the Earth's axis of rotatio...
Main Authors: | , , , , , , , |
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Format: | Article |
Language: | English |
Published: |
Copernicus Publications
2020-02-01
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Series: | Geoscientific Model Development |
Online Access: | https://www.geosci-model-dev.net/13/685/2020/gmd-13-685-2020.pdf |
Summary: | <p>Numerical general circulation models of the atmosphere are generally
required to conserve mass and energy for their application to
climate studies.
Here we draw attention to another conserved global integral, viz.
the component of angular momentum (AM) along the Earth's axis of
rotation, which tends to receive less consideration.
We demonstrate the importance of global AM conservation in climate
simulations with the example of the Community Atmosphere Model (CAM)
with the finite-volume (FV) dynamical core, which produces a
noticeable numerical sink of AM.
We use a combination of mathematical analysis and numerical
diagnostics to pinpoint the main source of AM non-conservation in
CAM–FV. We then present a method to enforce global conservation of
AM, and we discuss the results in a hierarchy of numerical
simulations of the atmosphere of increasing complexity.
In line with theoretical expectations, we show that even a crude,
non-local enforcement of AM conservation in the simulations
consistently results in the mitigation of certain persistent model
biases.</p> |
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ISSN: | 1991-959X 1991-9603 |