This project is dedicated to the detailed study of secular variation. We extended a recent examination of the secular variation of the Earth's magnetic field from 1980 to 2000 to the time span 1957 to 2010. These models are of unprecedented detail to describe secular variation on decadal and sub-decadal time-scales, including geomagnetic impulses. Modeling of core-surface flow and investigation of the spatio-temporal structure of geomagnetic jerks at the core-mantle boundary are main goals of this project.