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A comparison of the momentum budget in reanalysis datasets during sudden stratospheric warming events.
- Source :
- Atmospheric Chemistry & Physics Discussions; 2017, p1-31, 31p
- Publication Year :
- 2017
-
Abstract
- The agreement between reanalysis datasets, in terms of the zonal-mean momentum budget, is evaluated during sudden stratospheric warming (SSW) events. It is revealed that there is a good agreement among datasets in the lower stratosphere and troposphere concerning zonal-mean zonal wind, but less so in the upper stratosphere. Forcing terms of the momentum equation are also relatively similar in the lower atmosphere, but their uncertainties are typically larger than uncertainties of the zonal wind tendency. Similar to zonal wind tendency, the agreement among forcing terms is degraded in the upper stratosphere. Discrepancies among reanalyses increase during the onset of SSW events, a period characterized by unusually large fluxes of planetary-scale waves from the troposphere to the stratosphere, and decrease substantially after the onset. While the largest uncertainties in the momentum budget originate from the Coriolis torque, momentum flux convergence also presents a non-negligible spread among the reanalyses. Such a spread is reduced in the latest reanalysis products, decreasing the uncertainty of the momentum budget. It is also found that the uncertainties of the momentum budget depend on the strength of SSW events: the strongest SSWs being subject to larger discrepancies among reanalyses. These uncertainties in stratospheric circulation, however, are not communicated to the troposphere. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 16807367
- Database :
- Complementary Index
- Journal :
- Atmospheric Chemistry & Physics Discussions
- Publication Type :
- Academic Journal
- Accession number :
- 126517936
- Full Text :
- https://doi.org/10.5194/acp-2017-837