Figure 7: Cross correlations between N34   and mean surface temperature over the sectors: Pacific (120$^\circ$E-90$^\circ$W), Atlantic (90$^\circ$W-0$^\circ$), and Indian (0-120$^\circ$E) for 1979-98 (top), 1950-78 (bottom) as a function of lead and lag. Positive values mean that N34  leads.