Atmospheric Circulation Regimes in a Nonlinear Quasi-Geostrophic Model

Figure 13

(Left) estimated probability density in the space spanned by the first two PCs of the 833 hPa geopotential height for experiment I with a surface friction timescale of 0.66 days. Contour interval is 0.02; zero contour omitted. The thick lines enclose areas with significantly higher probability than to what be expected in the case of adapted red noise process (at the 90% significance level) and thus mark the circulation regimes. The regimes are denoted as indicated in the text. (Right) as left figure, but for experiment II with a surface friction timescale of 1.73 days and 99% level of significance.