Fig. 3From: Improvements and validation of the IRI UP method under moderate, strong, and severe geomagnetic stormsExamples of discarded effective index variograms and maps. Examples of discarded variogram models (linear (top left), Gaussian (bottom left)), with corresponding maps of IG12eff (top right) and R12eff (bottom right), on March 20, 2015, at 16:00 UTBack to article page