Fig. 3From: Analysis of temporal–longitudinal–latitudinal characteristics in the global ionosphere based on tensor rank-1 decompositionThe large-scale longitudinal variation in the ionosphere for the 12 UTs. The red dotted line indicates the longitude position of the maximum \(U^{(2)}\). The black dotted line indicates the longitude position of the maximum solar irradiation. The x-axis is the geographic longitude, ranging from \(-\,180^{\circ }\) to \(180^{\circ }\)Back to article page