World Magnetic Model
The World Magnetic Model (WMM) is a large spatial-scale representation of the Earth's magnetic field. It was developed jointly by the US
The model consists of a degree and order 12
WMM is the standard geomagnetic model of the
Updated model coefficients are released at 5-year intervals, with WMM2015 (released Dec 15, 2014) supposed to last until December 31, 2019. However, due to extraordinarily large and erratic movements of the north magnetic pole, an out-of-cycle update (WMM2015v2) was released in February 2019[4] (delayed by a few weeks due to the U.S. federal government shutdown)[5] to accurately model the magnetic field above 55° north latitude until the end of 2019. The next regular update (WMM2020) occurred in December 2019.[6]
Enhanced Magnetic Model (EMM)
The Enhanced Magnetic Model (EMM) is a sister product of the NGDC featuring a much higher amount of data to degree and order 790, giving a wavelength of 51 km as opposed to the 3000 km of WMM. At this resolution, it is not only able to model the
See also
- International Geomagnetic Reference Field: another model, of similar quality, which models past years as well
- Runway numbering
References
- ISBN 1107354803.
- ^ Chulliat, Arnaud; et al. "The US/UK World Magnetic Model for 2015-2020" (PDF). ngdc.noaa.gov. NOAA.
- ^ "Airport Runway Names Shift with Magnetic Field". National Centers for Environmental Information (NCEI). 16 November 2017.
- ^ "The World Magnetic Model and Associated Software". National Centers for Environmental Information. 4 February 2019. Retrieved 6 February 2019.
- PMID 30626958.
- ^ "World Magnetic Model | NCEI".
- ^ National Centers for Environmental Information (NCEI). "Enhanced Magnetic Model (EMM)". www.ngdc.noaa.gov.