Image showing composite polar vortex structure for disturbed conditions.
Composite polar vortex structure (10 hectopascals (hPa) geopotential height) for disturbed conditions following a stratospheric sudden warming (SSW), comparing results from ERA reanalyses (top) and multimodel CMIP6 averages (bottom). Composites are constructed according to so-called displacement or split-vortex SSW events. Credit: Hall et al. [2022], Figure 5
Editors’ Highlights are summaries of recent papers by AGU’s journal editors.
Source: Journal of Geophysical Research: Atmospheres

There is currently substantial interest in large-scale stratosphere-troposphere coupling, in particular regarding the surface effects of large mid-winter disturbances of the stratospheric polar vortex termed stratospheric sudden warmings (SSWs).

Hall et al. [2022] evaluated the statistical behavior of SSW coupling to the surface in 10 global climate models contributing to the Climate Model Intercomparison Project (CMIP6), and compared model results with historical observations based on reanalysis data. Individual CMIP6 models capture the main spatial features of surface impacts, including a negative phase of the Northern Annular Mode (NAM), with distinctive alternating positive and negative sea level pressure and temperature anomalies across the Northern Hemisphere. Time evolution of the surface impacts and regionally localized temperature responses vary among the different models.

These analyses help refine understanding of model behavior and uncertainty, and the results can lead to improved application of model predictions for societal impacts.

Citation: Hall, R. J., Mitchell, D. M., Seviour, W. J. M, & Wright, C. J. (2022). How well are sudden stratospheric warming surface impacts captured in CMIP6 climate models? Journal of Geophysical Research: Atmospheres, 127, e2021JD035725.

—William J. Randel, Editor, Journal of Geophysical Research: Atmospheres

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