On the representation of major stratospheric warmings in reanalyses
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Publication date
2019
Authors
Palmeiro Nuñez, Froila María
Langematz, Ulrike
Shibata, Kiyotaka
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Copernicus publications
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Abstract
Major sudden stratospheric warmings (SSWs) represent one of the most abrupt phenomena of the boreal wintertime stratospheric variability, and constitute the clearest example of coupling between the stratosphere and the troposphere. A good representation of SSWs in climate models is required to reduce their biases and uncertainties in future projections of stratospheric variability. The ability of models to reproduce these phenomena is usually assessed with just one reanalysis. However, the number of reanalyses has increased in the last decade and their own biases may affect the model evaluation. Here we compare the representation of the main aspects of SSWs across reanalyses. The examination of their main characteristics in the pre- and post-satellite periods reveals that reanalyses behave very similarly in both periods. However, discrepancies are larger in the pre-satellite period compared to afterwards, particularly for the NCEP-NCAR reanalysis. All datasets reproduce similarly the specific features of wavenumber-1 and wavenumber-2 SSWs. A good agreement among reanalyses is also found for triggering mechanisms, tropospheric precursors, and surface response. In particular, differences in blocking precursor activity of SSWs across reanalyses are much smaller than between blocking definitions.
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© Author(s) 2019. This research has been supported by the FP7 Environment (STRATOCLIM 603557 project under program FP7- ENV.2013.6.1-2), the Spanish Ministry of Economy and Competitiveness (PALEOSTRAT project, grant no. CGL2015-69699-R), and Blanca Ayarzagüena was funded by the Universidad Complutense de Madrid (Ayudas para la contratación de personal postdoctoral de formación en docencia e investigación en los departamentos de la UCM project).