Impact of parametrized nonorographic gravity wave drag on stratosphere-troposphere coupling in the northern and southern hemispheres

Polichtchouk, I., Shepherd, T. G. ORCID: https://orcid.org/0000-0002-6631-9968 and Byrne, N. J. (2018) Impact of parametrized nonorographic gravity wave drag on stratosphere-troposphere coupling in the northern and southern hemispheres. Geophysical Research Letters, 45 (16). pp. 8612-8618. ISSN 0094-8276 doi: 10.1029/2018GL078981

Abstract/Summary

The impact of parametrized nonorographic gravity wave drag (NOGWD) on the stratosphere-troposphere dynamical coupling in atmospheric models is relatively unexplored. Using the European Centre for Medium-Range Weather Forecasts Integrated Forecast System, we find that changes in NOGWD strength have a substantial impact on the tropospheric eddy-driven jet (EDJ) in both hemispheres, but the sense of the impact is opposite in the two hemispheres. In the Northern Hemisphere the impact occurs via changes in the amplitude and persistence of stratospheric anomalies. In the Southern Hemisphere (SH) it occurs instead via differences in the sensitivity of the EDJ to a given stratospheric anomaly, arising from changes in the seasonal cycle leading up to the polar vortex breakdown. Increasing NOGWD eliminates the springtime phase of the SH tropospheric semiannual oscillation (SAO), resulting in a more equatorward annual-mean EDJ, and showing that the SAO cannot be explained entirely from tropospheric mechanisms.

Item Type	Article
URI	https://reading-clone.eprints-hosting.org/id/eprint/78395
Item Type	Article
Refereed	Yes
Divisions	Science > School of Mathematical, Physical and Computational Sciences > Department of Meteorology
Publisher	American Geophysical Union
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