Streamfunctions of the equivalent current for the ionospheric field (⁠|$\Psi ^{\mathrm{ion}}$|⁠) on magnetic quiet days close to a spring equinox (left column) and a summer solstice (right column). The streamfunction is cut off above an absolute latitude of 70 degrees to filter out the values in high latitudes where our data set and parametrization have limited resolution. The central longitude for each subplot is at the local noon.