Fig. 2
From: Inverting magnetic meridian data using nonlinear optimization
Russian chain latitude profiles on April 1, 1986. Two stations slightly displaced in longitude at latitude 62° have slightly differing data values. Dots indicate observations and lines are the model fit. Local magnetic X M (black), Y M (red), and Z (blue) components are shown. Times progress by rows from bottom and are: (a) 18:30 UT (b) 18:50 UT (c) 19:00 UT (d) 19:30 UT