Fig. 2From: A framework for estimating spherical vector fields using localized basis functions and its application to SuperDARN data processingThe latitudinal profile of the azimuthal drift velocity at 3h MLT obtained by fitting to the Weimer’s empirical model. The red line indicates the reconstruction with the proposed basis functions, the blue line indicates the reconstruction with the original SECS functions, and the green line indicates the Weimer’s modelBack to article page