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On the Lack of Stratospheric Dynamical Variability in Low-top Versions of the CMIP5 Models
- Source :
- Journal of Geophysical Research: Atmospheres. 118(Isue 6)
- Publication Year :
- 2013
- Publisher :
- United States: NASA Center for Aerospace Information (CASI), 2013.
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Abstract
- We describe the main differences in simulations of stratospheric climate and variability by models within the fifth Coupled Model Intercomparison Project (CMIP5) that have a model top above the stratopause and relatively fine stratospheric vertical resolution (high-top), and those that have a model top below the stratopause (low-top). Although the simulation of mean stratospheric climate by the two model ensembles is similar, the low-top model ensemble has very weak stratospheric variability on daily and interannual time scales. The frequency of major sudden stratospheric warming events is strongly underestimated by the low-top models with less than half the frequency of events observed in the reanalysis data and high-top models. The lack of stratospheric variability in the low-top models affects their stratosphere-troposphere coupling, resulting in short-lived anomalies in the Northern Annular Mode, which do not produce long-lasting tropospheric impacts, as seen in observations. The lack of stratospheric variability, however, does not appear to have any impact on the ability of the low-top models to reproduce past stratospheric temperature trends. We find little improvement in the simulation of decadal variability for the high-top models compared to the low-top, which is likely related to the fact that neither ensemble produces a realistic dynamical response to volcanic eruptions.
- Subjects :
- Meteorology And Climatology
Subjects
Details
- Language :
- English
- Volume :
- 118
- Issue :
- Isue 6
- Database :
- NASA Technical Reports
- Journal :
- Journal of Geophysical Research: Atmospheres
- Notes :
- DOE DE-FOA-000024, , NSF ARC-1107384, , WBS 509496.02.08.04.24
- Publication Type :
- Report
- Accession number :
- edsnas.20140011364
- Document Type :
- Report
- Full Text :
- https://doi.org/10.1002/jgrd.50125