Evolution of the stratospheric polar vortex in the Southern Hemisphere over the period 1979 - 2016
Abstract
The stratospheric polar vortex in the Southern Hemisphere plays an important role in the intensity of the stratospheric ozone destruction during austral spring, which started in the late 1970s. The so-called ozone hole has in turn influenced the evolution of weather patterns in the Southern Hemisphere in the last decades (WMO, 2018) The seasonal and interannual evolution of the Southern polar vortex has been analyzed using meteorological fields from the European Center for Meteorology Weather Forecasts ERA-Interim reanalyses and the MIMOSA model (Modélisation Isentrope du transport Méso-échelle de l'Ozone Stratosphérique par Advection, Hauchecorne et al., 2002). This model provides potential vorticity (PV) fields at several isentropic levels (475 K, 550 K and 675 K) that are used to evaluate the edge and intensity of the polar vortex as a function of time from 1979 to 2016. The edge of the vortex is computed on isentropic surfaces from the wind and gradient of PV as a function of equivalent latitude (e.g. Nash et al, 1996; Godin et al., 2001). In order to remove the noise of PV gradient determination, tracers have been incorporated into the model, tracking air masses inside and outside the vortex as a function of time. Results on the statistical analysis of the seasonal and interannual evolution of the intensity and extension of the southern polar vortex over the last 3 decades will be presented. References: Godin S., V. Bergeret, S. Bekki, C. David, G. Mégie, Study of the interannual ozone loss and the permeability of the Antarctic Polar Vortex from long-term aerosol and ozone lidar measurements in Dumont d'Urville (66.4°S, 140°E), J. Geophys. Res., 106, 1311-1330, 2001 Hauchecorne, A., S. Godin, M. Marchand, B. Hesse, and C. Souprayen, Quantification of the transport of chemical constituents from the polar vortex to midlatitudes in the lower stratosphere using the high-resolution advection model MIMOSA and effective diffusivity, J. Geophys. Res., 107 (D20), 8289, doi:10.1029/2001JD000491, 2002 Nash, E. R., Newman, P. A., Rosenfield, J. E., and Schoeberl, M. R. (1996), An objective determination of the polar vortex using Ertel's potential vorticity, Journal of geophysical research, VOL.101(D5), 9471- 9478 World Meteorological Organization, Global Ozone Research and Monitoring Project - Report No. 58, 2018.
- Publication:
-
EGU General Assembly Conference Abstracts
- Pub Date:
- April 2019
- Bibcode:
- 2019EGUGA..21.9061L