Estimated ACF (normalized) ﹩{\hat{R}}_{b}(\ell )={\hat{C}}_{b}(\ell )/{\hat{C}}_{b}(0)﹩ and ﹩{\hat{R}}_{h}(\ell )={\hat{C}}_{h}(\ell )/{\hat{C}}_{h}(0)﹩ vs. τ_ℓ = ℓδt, with signal centered around the local mean (LM) vs. global mean (GM) for different interval lengths T. Note that the unbiased ACF is estimated up to a maximum lag equal to half the selected interval length. Top left: estimated ﹩{\hat{R}}_{b}(\ell )﹩ calculated with magnetic field interval centered around its own (local) mean. Top right: estimated ﹩{\hat{R}}_{b}(\ell )﹩ calculated with magnetic field interval centered around the ensemble (global) mean. Bottom left: estimated ﹩{\hat{R}}_{h}(\ell )﹩ calculated with magnetic field interval centered around its own (local) mean. Bottom right: estimated ﹩{\hat{R}}_{h}(\ell )﹩ calculated with magnetic field interval centered around the ensemble (global) mean.