Fig. 1.From: On the possibility of extending the IGRF predictive secular variation model to a higher SH degreePer degree correlations between mean secular variations: solid line, SV1 (mean secular variation between 1980 and 1999) and SV3 (mean secular variation between 1999 and 2004); dashes, SV2 (mean secular variation between 1994 and 1999) and SV3; dots, SV3 and SV4 (mean secular variation between 2004 and 2009).Back to article page