Fig. 7From: Analysis of temporal–longitudinal–latitudinal characteristics in the global ionosphere based on tensor rank-1 decompositionThe diurnal variations in NSA indicated by \(U^{(3)}\). The red, black dotted, and black dotted dash lines indicate the positions of the barycenters, and south and north maxima of \(U^{(3)}\), respectively. The x-axis is the latitude ranging from \(-\,87.5^{\circ }\) to \(87.5^{\circ }\). a Results for daytime. b Results for nightBack to article page