Fig. 2
From: Stratospheric ozone loss over the Eurasian continent induced by the polar vortex shift
Eurasia-North America dipole mode of total column ozone and clear-sky ultraviolet radiation. a–c Spatial patterns of Eurasia-North America dipole (ENAD) mode (EOF2 + EOF3) and d–f time series of normalized ENAD index (principal component (PC)2 + PC3) (blue lines) of February mean total column ozone (TCO) over 45–90°N derived from a, d MSR2 data and b, e SLIMCAT full chemistry simulation, and c, f February mean clear-sky ultraviolet radiation index derived from MSR2 data. Time series of vortex shift index (see Methods section, red lines) are overlaid in d–f. The percentage of explained variance is shown in the top right of a–c, and the correlation coefficients between PC2 + PC3 and the vortex shift index are shown in the top right of captions in d–f. Linear trends of g MSR2 TCO, h SLIMCAT TCO and i MSR2 UV index regressed on the vortex shift index are also shown. The linear trends over the dotted regions are statistically significant at the 90% confidence level according to the Student’s t test. The minimum latitude of polar stereographic projections is 45°N. The values in 1987, 2006 and 2009 are not included because the polar vortex broke up and its shape was distorted during February in these years (Methods)
