TY - JOUR

T1 - The nature of Arctic polar vortices in chemistry-climate models

AU - Mitchell, D. M.

AU - Charlton-Perez, A. J.

AU - Gray, L. J.

AU - Akiyoshi, H.

AU - Butchart, N.

AU - Hardiman, S. C.

AU - Morgenstern, O.

AU - Nakamura, T.

AU - Rozanov, E.

AU - Shibata, K.

AU - Smale, D.

AU - Yamashita, Y.

PY - 2012/10

Y1 - 2012/10

N2 - The structure of the Arctic stratospheric polar vortex in three chemistryclimate models (CCMs) taken from the CCMVal-2 intercomparison is examined using zonal mean and geometric-based methods. The geometric methods are employed by taking 2D moments of potential vorticity fields that are representative of the polar vortices in each of the models. This allows the vortex area, centroid location and ellipticity to be determined, as well as a measure of vortex filamentation. The first part of the study uses these diagnostics to examine how well the mean state, variability and extreme variability of the polar vortices are represented in CCMs compared to ERA-40 reanalysis data, and in particular for the UMUKCA-METO, NIWA-SOCOL and CCSR/NIES models. The second part of the study assesses how the vortices are predicted to change in terms of the frequency of sudden stratospheric warmings and their general structure over the period 19602100. In general, it is found that the vortices are climatologically too far poleward in the CCMs and produce too few large-scale filamentation events. Only a small increase is observed in the frequency of sudden stratospheric warming events from the mean of the CCMVal-2 models, but the distribution of extreme variability throughout the winter period is shown to change towards the end of the twentyfirst century. Copyright (c) 2012 Royal Meteorological Society and British Crown Copyright, the Met Office

AB - The structure of the Arctic stratospheric polar vortex in three chemistryclimate models (CCMs) taken from the CCMVal-2 intercomparison is examined using zonal mean and geometric-based methods. The geometric methods are employed by taking 2D moments of potential vorticity fields that are representative of the polar vortices in each of the models. This allows the vortex area, centroid location and ellipticity to be determined, as well as a measure of vortex filamentation. The first part of the study uses these diagnostics to examine how well the mean state, variability and extreme variability of the polar vortices are represented in CCMs compared to ERA-40 reanalysis data, and in particular for the UMUKCA-METO, NIWA-SOCOL and CCSR/NIES models. The second part of the study assesses how the vortices are predicted to change in terms of the frequency of sudden stratospheric warmings and their general structure over the period 19602100. In general, it is found that the vortices are climatologically too far poleward in the CCMs and produce too few large-scale filamentation events. Only a small increase is observed in the frequency of sudden stratospheric warming events from the mean of the CCMVal-2 models, but the distribution of extreme variability throughout the winter period is shown to change towards the end of the twentyfirst century. Copyright (c) 2012 Royal Meteorological Society and British Crown Copyright, the Met Office

KW - stratosphere

KW - CCMVal

KW - moments

KW - potential vorticity

KW - ERA-40

KW - STRATOSPHERIC SUDDEN WARMINGS

KW - VERTICALLY EXTENDED VERSION

KW - MIDDLE ATMOSPHERE

KW - PART III

KW - VORTEX

KW - VARIABILITY

KW - WEATHER

U2 - 10.1002/qj.1909

DO - 10.1002/qj.1909

M3 - статья

VL - 138

SP - 1681

EP - 1691

JO - Quarterly Journal of the Royal Meteorological Society

JF - Quarterly Journal of the Royal Meteorological Society

SN - 0035-9009

IS - 668

ER -