Fig. 4 Decay curves of 500-mb anomaly correlations for geopotential as a function of forecast length, averaged over all July-Aug cases (N=35). Northern Hemisphere on top, Southern Hemisphere on the bottom. The three models of interest are the then-operational T170 MRF in black and the new T126 and T170 corrected versions under consideration here. The dotted red lines are the T126; the solid green lines are new T170. Northern Hemisphere is on top and Southern Hemisphere on the bottom, as in Fig. 3.