Forecasting secular variation from CHAMP to Swarm

The ability to generate accurate forecasts of magnetic field change over a five year period is an active area of research. Models of the main field and its secular variation (SV) have been relatively poorly constrained without global high-quality vector satellite data during three year period from the de-orbiting of CHAMP to the launch of Swarm. We examine forecasts of main magnetic field change between 2010.0 and 2014.0 using the latest BGS field model based on the first data from Swarm (see accompanying poster by Macmillan and Hamilton) as the ‘true’ model. We compare the forecasts of the World Magnetic Model and International Geomagnetic Reference Field (both released in late 2009) to our main field model to establish how close each one is to the 'true' variation of the field over the past four years. We also show the comparison to the SV forecast from a steady core flow and acceleration model using magnetic data from 2007-2010. In addition, we show the comparison with the recently released DMSP-MAG-1 model.