The US/UK World Magnetic Model for 2020-2025

This report contains a complete description of the World Magnetic Model (WMM) 2020. Section 1 contains information that users of WMM2020 require in order to implement the model and software in navigation and heading systems, and to understand magnetic charts, poles and geomagnetic coordinate systems. Section 2 contains a detailed summary of the data used and the modeling techniques employed. Section 3 contains an assessment of the model uncertainties and a description of the error model provided with the WMM2020. Section 4 contains charts of all the magnetic elements at 2020.0 and their expected annual rates of change between 2020.0 and 2025.0. These predicted changes are based upon the best knowledge of the geomagnetic main field evolution at the time the WMM was released. Sponsored by the U.S. National Geospatial-Intelligence Agency (NGA) and the U.K. Defence Geographic Centre (DGC), the World Magnetic Model (WMM) is produced by the U.S. National Oceanic and Atmospheric Administration’s National Centers for Environmental Information (NOAA/NCEI) and the British Geological Survey (BGS). It is the standard model used by the U.S. Department of Defense (DoD), the U.K. Ministry of Defence, the North Atlantic Treaty Organization (NATO) and the International Hydrographic Organization (IHO), for navigation, attitude and heading referencing systems using the geomagnetic field. It is also used widely in civilian navigation and heading systems.