Data on the Earth’s Magnetic Field and its Secular Change since 1800View Metadata As: Get Data, FAQ, HTML, 19139 XML
Assess Metadata For: Completeness, DOI Readiness, CSW Readiness, Components
Data on the Earth’s Magnetic Field and its Secular Change since 1800
Information on the past and present orientation of the Earth’s magnetic field is available from the National Geophysical Data Center (NGDC) which serves as the national data bank for geomagnetic data. The Earth’s magnetic field has been measured by land surveys, ships, aircraft and satellites at hundreds of locations resulting in millions of observations. Many of the observations are of poor quality or are unevenly distributed around the globe. Because of these limiting factors and the variation of the main magnetic field with time, the Earth’s field is usually approximated by mathematical models. These models, adjusted to fit selected available observations, have wide application in geophysical and space sciences. Surveyors can obtain data and information for individual specific locations worldwide. Past values of the magnetic field are available from models for areas within the conterminous U.S. from 1750 or from 1945 worldwide. These mathematical models must be periodically updated due to the changing nature of the Earth’s magnetic field. NGDC maintains the models and data base of observations to track secular variation of the Earth’s magnetic field. Models and software are available on-line. The global geomagnetic observations data bases for secular change studies include high-quality magnetic observations made at observatories worldwide since 1800. Other geomagnetic data bases are: IAGA Repeat Station data base which contains observations from exact reoccupations, Other land Surveys containing miscellaneous land observations worldwide since 1800 including a few thousand observations made at sea by the non-magnetic ships, Carnegie and Zarya, Vector airborne surveys from the Project Magnetic aircraft, satellite and selected marine observations. Most of the surface data are available on-line. At most locations, three magnetic elements were observed: Either declination (D), Inclination (I), and horizontal intensity (H), or declination, horizontal intensity, and vertical intensity (Z), or total intensity (F). Where possible, the values for other magnetic elements, usually the north component (X) and east component (Y), were derived by the computer. The altitude, latitude, and longitude are recorded for each observation. The observatory annual means file contains the results of more of the observatories operating since 1800. Files are revised as new data become available. Searches and plots of data from selected stations can be made. These secular change files are the principal source for tracking the long-period changes in the direction and intensity of the Earth’s magnetic field. Other data include a digital bibliography of historical magnetic survey publications at NGDC and the co-located World Data Center-A. Over 750 reports published from the 1830’s to 1980’s were inventoried in a digital bibliography and digitally imaged in .PCX format. The digital images of these reports have been written to magnetic tape.

Get the Data
AccessFormat(s)Distributor(s) / Contact InfoInstructions / Constraints
information
Geomagnetic Data
Home page
download
Geomagnetic Data On-line
Web page where different Geomagnetic data may be downloaded from
TIFF
Format version: (version is unknown)
DOC/NOAA/NESDIS/NGDC - National Geophysical Data Center
DOC/NOAA/NESDIS/NGDC - National Geophysical Data Center
303-497-6826
8am-5pm, Monday through Friday
Fees
Depends on the Data Set

Ordering Instructions
Ordering Instructions: Price information is available upon request. Custom Order Process: Contact Data Center

Use Limitation
While every effort has been made to ensure that these data are accurate and reliable within the limits of the current state of the art, NOAA cannot assume liability for any damages caused by any errors or omissions in the data, nor as a result of the failure of the data to function on a particular system. NOAA makes no warranty, expressed or implied, nor does the fact of distribution constitute such a warranty.

Legal Constraints
Use Limitation
otherRestrictions

Other
Use Constraints: None

Access
otherRestrictions

Other
Access Constraints: No Constraints