FIG. 7. Sampling error for the averaging box of L = 150, M = 20 and T=4weeks for high-passed SST estimated from (a) observation; (b) sampling error formula by Nakamoto et al. (1994) with γ0 = 90 days; and new formula Eq. (24) with (c) γ0 = 1.75 days and (d) γ0 = 0.31γe. The contour interval is 5%.
