Three measured travel-time shifts (from left to right), δτ′_sn;23, δτ′_sn;24, and δτ′_sn;23+24, averaged over four distance ranges and antisymmetrized about the equator, as a function of latitude (curves with error bars). Each row corresponds to a distance range indicated in the first column; shortest at the top and largest at the bottom. The data values are binned every 7.2° in latitude. The error bars give the standard deviation of the mean in each binning interval. For comparison, we overplot the selected forward-modeled travel-time shifts (see the legend on the right) averaged over the same distance ranges as for δτ′_sns. As mentioned in Sect. 4.1, the parameters of the flow models were chosen such that the forward-modeled travel-time shifts are comparable to the measured δτ′_sns in the top row.