Interannual variability in the gravity wave drag – vertical coupling and possible climate links
Gravity wave drag (GWD) is an important driver of the middle atmospheric dynamics. However, there are almost no observational constraints on its strength and distribution (especially horizontal). In this study we analyze orographic GWD (OGWD) output from Canadian Middle Atmosphere Model simulation w...
Published in: | Earth System Dynamics |
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Main Authors: | , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
Earth System Dynamics
2018
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Subjects: | |
Online Access: | http://hdl.handle.net/11093/4286 https://doi.org/10.5194/esd-9-647-2018 https://esd.copernicus.org/articles/9/647/2018/ |
Summary: | Gravity wave drag (GWD) is an important driver of the middle atmospheric dynamics. However, there are almost no observational constraints on its strength and distribution (especially horizontal). In this study we analyze orographic GWD (OGWD) output from Canadian Middle Atmosphere Model simulation with specified dynamics (CMAM-sd) to illustrate the interannual variability in the OGWD distribution at particular pressure levels in the stratosphere and its relation to major climate oscillations. We have found significant changes in the OGWD distribution and strength depending on the phase of the North Atlantic Oscillation (NAO), quasi-biennial oscillation (QBO) and El Niño–Southern Oscillation. The OGWD variability is shown to be induced by lower-tropospheric wind variations to a large extent, and there is also significant variability detected in near-surface momentum fluxes. We argue that the orographic gravity waves (OGWs) and gravity waves (GWs) in general can be a quick mediator of the tropospheric variability into the stratosphere as the modifications of the OGWD distribution can result in different impacts on the stratospheric dynamics during different phases of the studied climate oscillations. Grantová Agentura České Republiky | Ref. 16-01562J Secretaría de Estado de Investigación, Desarrollo e Innovación | Ref. CGL2015-71575-P Grantová Agentura České Republiky | Ref. 18-01625S |
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