A southern Africa harmonic spline core field model derived from CHAMP satellite data

A harmonic spline magnetic main field model for Southern Africa combining ground and satellite data to describe the evolution of the South Atlantic Anomaly in this region between 2005 and 2010

“…Three groups of input data, the satellite data, the observatory data and the repeat station data, and one group of independent data of three reference ground points were used to evaluate the SACFM-2 model in comparison with the regional model SARM (Nahayo et al 2015) and global model CHAOS-6. The independent data at satellite level were also used to compare the performance of both SACFM-2 and CHAOS-6 models (Tables 5 and 6).…”

“…Fares Saba et al 1997), was therefore exclusively used in data selection. Before setting the data selection criterion of Dst values to be between − 20 and 0 nT (Nahayo et al 2015) a trade-off was made between getting quiet time data and a good data coverage.…”

“…Regional field studies of the long-term time variation of the geomagnetic field in southern Africa using the harmonic spline technique were conducted before using only either ground-based data ) or satellite data (Nahayo et al 2015). The method is summarised in section "Methods", and the utilised data are described in section "Data selection and processing".…”

A regional geomagnetic field model over Southern Africa derived with harmonic splines from Swarm satellite and ground-based data recorded between 2014 and 2019

“…The southern African region has also been known for many years to have high spatial and temporal field variations with strong abrupt changes in the linear geomagnetic secular variation (Mandea et al, 2007;Kotzé and Korte, 2016;Kotzé, 2020). Some scholars have recently conducted studies of rapid geomagnetic time variations in southern Africa using regional models (Geese et al, 2009(Geese et al, , 2011Nahayo and Kotzé, 2012;Nahayo et al, 2015Nahayo et al, , 2018.…”