Description: Intercomparison of gravity waves in global convection-permitting models

This title appears in the Scientific Report : 2019

Intercomparison of gravity waves in global convection-permitting models

Large uncertainties remain with respect to the representation of atmospheric gravity waves (GWs) in General Circulation Models (GCMs) with coarse grids. Insufficient parameterizations result from a lack of observational constraints on the parameters used in GW parameterizations as well as from physi...

Personal Name(s):	Stephan, Claudia Christine (Corresponding author)
	Strube, Cornelia / Klocke, Daniel / Ern, Manfred / Hoffmann, Lars / Preusse, Peter / Schmidt, Hauke
Contributing Institute:	Jülich Supercomputing Center; JSC Stratosphäre; IEK-7
Published in:	Journal of the atmospheric sciences, 76 (2019) 9, S. 2739–2759
Imprint:	Boston, Mass. American Meteorological Soc. 2019
DOI:	10.1175/JAS-D-19-0040.1
Document Type:	Journal Article
Research Program:	Composition and dynamics of the upper troposphere and middle atmosphere Computational Science and Mathematical Methods
Link:	Published on 2019-08-21. Available in OpenAccess from 2020-02-21.
	Publikationsportal JuSER

Please use the identifier: http://hdl.handle.net/2128/22743 in citations.
Please use the identifier: http://dx.doi.org/10.1175/JAS-D-19-0040.1 in citations.

Large uncertainties remain with respect to the representation of atmospheric gravity waves (GWs) in General Circulation Models (GCMs) with coarse grids. Insufficient parameterizations result from a lack of observational constraints on the parameters used in GW parameterizations as well as from physical inconsistencies between parameterizations and reality. For instance, parameterizations make oversimplifying assumptions about the generation and propagation of GWs. Increasing computational capabilities now allow GCMs to run at grid spacings that are sufficiently fine to resolve a major fraction of the GW spectrum. This study presents the first intercomparison of resolved GW pseudo-momentum fluxes (GWMFs) in global convection-permitting simulations and those derived from satellite observations. Six simulations of three different GCMs are analyzed over the period of one month of August to assess the sensitivity of GWMF to model formulation and horizontal grid spacing. The simulations reproduce detailed observed features of the global GWMF distribution, which can be attributed to realistic GWs from convection, orography and storm tracks. Yet, the GWMF magnitudes differ substantially between simulations. Differences in the strength of convection may help explain differences in the GWMF between simulations of the same model in the summer low latitudes where convection is the primary source. Across models, there is no evidence for a systematic change with resolution. Instead, GWMF is strongly affected by model formulation. The results imply that validating the realism of simulated GWs across the entire resolved spectrum will remain a difficult challenge not least because of a lack of appropriate observational data.