Fig. 3From: Building the second version of the World Digital Magnetic Anomaly Map (WDMAM)Global power spectra of models of the Earth’s lithospheric magnetic field calculated at a reference radius of 6371.2 km. The spectra for models with different regularisation parameter values (d=1,10,100) are presented. The spectrum for the chosen parameter d=5 is shown in red and the spectrum of the EMM2015 is shown in green Back to article page