This new relation, E ∼ , actually represents the character of the rainstorm for the two geographically separated pond systems: the first system from the four ponds p1,...,p4 and the second system from the ponds p5,...,p9. If the numbers in this relation are large, it means that the rainstorm is widespread, whereas if the numbers are closer to zero, then the rainstorm is more localized and the original rain gauges are not a good predictor for both systems.