Unforced, Forced and Resonance-Forced Waves in a Spherical Atmosphere
This technical report discusses a longstanding issue of atmospheric tides in weather-prediction and general circulation models (GCMs). Tidal signatures consistent with observations have appeared in the surface pressure output of GCMs since their inception (Hardy 1968, Hunt and Manabe 1968). Such models, however, are sufficiently complicated that the possibility of “getting the right answer for the wrong reasons” arises. Lindzen et al. (1968, hereafter LBK) showed that wave reflection at the upper boundary of a GCM can artificially enhance the tides. Covey et al. (2011, 2014) found that tidal output from a number of modern GCMs is surprisingly independent of their forcing. This finding is consistent with earlier suggestions that a compensating effect occurs in some models: lowering the model top reduces the forcing (solar heating of the ozone layer) but also enhances spurious wave reflection (Zwiers and Hamilton 1986, Hamilton et al. 2008).
- Publication Date:
- OSTI Identifier:
- Report Number(s):
- DOE Contract Number:
- Resource Type:
- Technical Report
- Research Org:
- Lawrence Livermore National Laboratory (LLNL), Livermore, CA
- Sponsoring Org:
- Country of Publication:
- United States
- 58 GEOSCIENCES; 97 MATHEMATICS AND COMPUTING
Enter terms in the toolbar above to search the full text of this document for pages containing specific keywords.