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Enhanced Magnetic Model 2015

browse graphicDeclination Comparison of WMM and EMM
The Enhanced Magnetic Model (EMM) extends to degree and order 720, resolving magnetic anomalies down to 56 km wavelength. The higher resolution of the EMM results in significantly improved pointing accuracy than the World Magnetic Model (WMM), which uses spherical harmonic representation to degree and order 12, resolving the magnetic field at 3000 km wavelength. The EMM model provides the magnetic field vector at any desired location and altitude close to and above the Earth's surface.
  • Cite as: Chulliat, A.. P. Alken. Nair, A. Woods. S. Maus. 2015: Enhanced Magnetic Model 2015. 1. NOAA National Centers for Environmental Information. https://doi.org/10.7289/V56971HV. Accessed [date].
gov.noaa.ngdc.mgg.geophysical_models:EMM2015
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Download Data
  • EMM2015_Sph_Linux.zip (download)
    Enhanced Magnetic Model (EMM2015) and software using the spherical harmonic approach for Linux environments. High CPU requirements (use the faster Mesh software for large number of points), very low RAM requirement. For use with years 2000 to 2020.
  • EMM2015_Sph_Windows.zip (download)
    Enhanced Magnetic Model (EMM2015) and software using the spherical harmonic approach for Windows environments. High CPU requirements (use the faster Mesh software for large number of points), very low RAM requirement. For use with years 2000 to 2020.
  • EMM2015_Sph_Mac.zip (download)
    Enhanced Magnetic Model (EMM2015) and software using the spherical harmonic approach for Mac environments. High CPU requirements (use the faster Mesh software for large number of points), very low RAM requirement. For use with years 2000 to 2020.
Distribution Formats
  • EMM2015_Sph_Linux.zip (Version: 4)
    • File Specification: Enhanced Magnetic Model (EMM2015) and software using the spherical harmonic approach for Linux environments. High CPU requirements (use the faster Mesh software for large number of points), very low RAM requirement. For use with years 2000 to 2020.
  • EMM2015_Sph_Windows.zip (Version: 4)
    • File Specification: Enhanced Magnetic Model (EMM2015) and software using the spherical harmonic approach for Windows environments. High CPU requirements (use the faster Mesh software for large number of points), very low RAM requirement. For use with years 2000 to 2020.
  • EMM2015_Sph_Mac.zip (Version: 4)
    • File Specification: Enhanced Magnetic Model (EMM2015) and software using the spherical harmonic approach for Mac environments. High CPU requirements (use the faster Mesh software for large number of points), very low RAM requirement. For use with years 2000 to 2020.
Ordering InstructionsContact NCEI for other distribution options and instructions.
DistributorNOAA National Centers for Environmental Information
ncei.info@noaa.gov
Dataset Point of Contact NOAA National Centers for Environmental Information
ncei.info@noaa.gov
Dataset Point of Contact NCEI Geomagnetic Modeling Team
NOAA National Centers for Environmental Information
geomag.models@noaa.gov
Time Period2000-01-01 to 2019-12-31
Spatial Reference Systemurn:ogc:def:crs:EPSG::4326
Spatial Bounding Box Coordinates
N: 90
S: -90
E: 180
W: -180
Spatial Coverage Map
General Documentation
Publication Dates
  • publication: 2015-05-15
Edition1
Data Presentation FormmapDigital
Dataset Progress StatusComplete - production of the data has been completed
Historical archive - data has been stored in an offline storage facility
Data Update Frequency As needed
PurposeMagnetic anomaly maps provide insight into the subsurface structure and composition of the Earth's crust. Over continental areas, magnetic anomalies illuminate geologic, tectonic, and geothermal evolution of crust and lithosphere. In the world's oceans, anomalies trending parallel to the isochrons (lines of equal age) reveal the temporal evolution of oceanic crust. Magnetic maps are widely used in the geological sciences and in resource exploration.
Use Limitations
  • Produced by the NOAA National Centers for Environmental Information. Not subject to copyright protection within the United States.
Dataset Citation
  • Cite as: Chulliat, A.. P. Alken. Nair, A. Woods. S. Maus. 2015: Enhanced Magnetic Model 2015. 1. NOAA National Centers for Environmental Information. https://doi.org/10.7289/V56971HV. Accessed [date].
Cited Authors
  • Chulliat, A.
  • P. Alken
  • Nair, A. Woods
  • S. Maus
Originators
  • NCEI Geomagnetic Modeling Team
Publishers
  • NOAA National Centers for Environmental Information
Theme keywordsGlobal Change Master Directory (GCMD) Science Keywords
  • Earth Science > Solid Earth > Geomagnetism > Magnetic Field
  • Earth Science > Solid Earth > Geomagnetism > Magnetic Intensity
  • Earth Science > Solid Earth > Geomagnetism > Magnetic Declination
  • Earth Science > Solid Earth > Geomagnetism > Magnetic Inclination
  • Earth Science > Solid Earth > Geomagnetism > Magnetic Anomalies
Data Center keywordsGlobal Change Master Directory (GCMD) Data Center Keywords
  • DOC/NOAA/NESDIS/NCEI > National Centers for Environmental Information, NESDIS, NOAA, U.S. Department of Commerce
  • DOC/NOAA/NESDIS/NGDC > National Geophysical Data Center, NESDIS, NOAA, U.S. Department of Commerce
Place keywordsGlobal Change Master Directory (GCMD) Location Keywords
  • Geographic Region > Global
Use Constraints
  • Use liability: NOAA and NCEI cannot provide any warranty as to the accuracy, reliability, or completeness of furnished data. Users assume responsibility to determine the usability of these data. The user is responsible for the results of any application of this data for other than its intended purpose.
Access Constraints
  • Distribution liability: NOAA and NCEI make no warranty, expressed or implied, regarding these data, nor does the fact of distribution constitute such a warranty. NOAA and NCEI cannot assume liability for any damages caused by any errors or omissions in these data. If appropriate, NCEI can only certify that the data it distributes are an authentic copy of the records that were accepted for inclusion in the NCEI archives.
Other ConstraintsCite as: Chulliat, A.. P. Alken. Nair, A. Woods. S. Maus. 2015: Enhanced Magnetic Model 2015. 1. NOAA National Centers for Environmental Information. https://doi.org/10.7289/V56971HV. Accessed [date].
Fees
  • In most cases, electronic downloads of the data are free. However, fees may apply for custom orders, data certifications, copies of analog materials, and data distribution on physical media.
Lineage information for: dataset
Processor
  • NOAA National Centers for Environmental Information
  • NOAA National Centers for Environmental Information
  • NOAA National Centers for Environmental Information
  • NOAA National Centers for Environmental Information
Processing Steps
  • Measurements during daytime and during periods of strong solar activity are contaminated by external current systems, which are difficult to accurately model. Therefore, only nighttime data during magnetically quiet periods were used in estimating the WMM coefficients.
  • Some contributions to the measured magnetic field, such as the diamagnetic effect of ionospheric plasma (Lühr et al, 2003) or motional induction by tidal ocean currents (Kuvshinov and Olsen, 2005; Maus, 2007), can be accurately modeled and were corrected for prior to the estimation of the WMM main field coefficients.
  • To account for the contributions that have not been removed in the previous steps, an extended set of model parameters is co-estimated with the WMM model coefficients. These account for smaller-wavelength internal magnetic field contributions (spherical harmonic degree larger than 12), second time derivatives (secular acceleration) and contributions from currents external to the Earth. The set of WMM coefficients plus the extended model parameters is called a parent model of the WMM. Two different parent models were produced, reflecting different modeling strategies employed by NGDC for the main field model and BGS for the secular variation model.
  • Satellite, marine, and aeromagnetic measurements were compiled into an ellipsoidal degree-720 magnetic model of the Earth's lithosphere. This model accurately represents the crustal field down to wavelengths of approximately 56 kilometers. This results in a higher pointing accuracy.
Source Datasets
  • Swarm Satellite Data
  • CHAMP Satellite Data
  • ORSTED Satellite Data
  • INTERMAGNET Observatory Data
  • GEODAS magnetic data
    • Description of Source: Trackline magnetics observations hosted on GEODAS at the National Centers for Environmental Information (NCEI).
    • Spatial extent used: N:90 S:-90 E:180 W:-180
Lineage information for: repository
Processing Steps
  • 2015-04-22T00:00:00 - NOAA created the National Centers for Environmental Information (NCEI) by merging NOAA's National Climatic Data Center (NCDC), National Geophysical Data Center (NGDC), and National Oceanographic Data Center (NODC), including the National Coastal Data Development Center (NCDDC), per the Consolidated and Further Continuing Appropriations Act, 2015, Public Law 113-235. NCEI launched publicly on April 22, 2015.
Last Modified: 2020-05-14
For questions about the information on this page, please email: ncei.info@noaa.gov