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Data on the Earth's Magnetic Field and its Secular Change since 1800

Entry ID: gov.noaa.ngdc.G01152

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Summary

Abstract: ABSTRACT: 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.

SUPPLEMENTAL INFORMATION: Formally FE 17, 119, 626

CURRENTNESS REFERENCE: Publication Date

DATA SET CREATOR: DOC/NOAA/NESDIS/NGDC > National Geophysical Data Center, NESDIS, NOAA, U.S. Department of Commerce (comp)

DATA SET PUBLISHER: SE-53, A Report on Geomagnetic Observatories, 1995. SE-51, Bibliography of Historical Geomagnetic Main Field Survey and Secular Variation Reports at the World Data Center-A for Solid Earth Geophysics.

Purpose: PURPOSE: Provide information for research and surveyors

Related URL

Link: GET DATA

Description: Home page

Link: GET DATA

Description: Web page where different Geomagnetic data may be downloaded from

Link: VIEW EXTENDED METADATA

Description: View Source Metadata document from the Metadata Manager and Repository (NMMR).

Link: VIEW RELATED INFORMATION

Description: Home page

Geographic Coverage

(Click for Interactive Map)

Spatial coordinates

N: 90.0

S: -90.0

E: 180.0

W: -180.0

Data Set Citation

Dataset Originator/Creator: Please See Summary

Dataset Title: Data on the Earth's Magnetic Field and its Secular Change since 1800

Dataset Series Name: Solid Earth (SE)

Dataset Release Date: 1972

Dataset Release Place: Boulder, CO

Dataset Publisher: National Geophysical Data Center

Version: First

Issue Identification: Please See Summary

Online Resource: http://www.ngdc.noaa.gov/seg/geomag/geomag.shtml

Temporal Coverage

Start Date: 1800-01-01

Science Keywords

SOLID EARTH > GEOMAGNETISM > GEOMAGNETIC FORECASTS

SOLID EARTH > GEOMAGNETISM > GEOMAGNETIC INDICES

ISO Topic Category

GEOSCIENTIFIC INFORMATION

Project

ESIP > Earth Science Information Partners Program

Access Constraints ACCESS CONSTRAINTS: No Constraints

DISTRIBUTION LIABILITY: 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.

CUSTOM ORDER PROCESS: Contact Data Center

Use Constraints None

Ancillary Keywords

WDC/SEG, BOULDER > World Data Center for Solid Earth Geophysics, Boulder

DOC/NOAA/NESDIS/NGDC > National Geophysical Data Center, NESDIS, NOAA, U.S. Department of Commerce

Data Set Progress

IN WORK

Data Center

National Geophysical Data Center, NESDIS, NOAA, U.S. Department of Commerce

Data Center URL: http://www.ngdc.noaa.gov/
Dataset ID: ______GEOMAGNETICS ____

Data Center Personnel
Name: NGDC USER SERVICES Phone: (303) 497-6826 Fax: (303) 497-6513 Email: ngdc.info at noaa.gov Contact Address: NOAA/NESDIS/NGDC E/GC 325 Broadway City: Boulder Province or State: CO Postal Code: 80305-3328 Country: USA

Distribution

Distribution Size: 26671.900000

Distribution Format: TIFF

Fees: Depends on the Data Set

Personnel

SUSAN MCLEAN

Role: TECHNICAL CONTACT

Role: DIF AUTHOR

Phone: (303) 497-6478

Fax: (303) 497-6513

Email: Susan.McLean at noaa.gov

Contact Address:

NOAA/NESDIS/NGDC

E/GC2 325 Broadway

City: Boulder

Province or State: CO

Postal Code: 80305-3328

Country: USA

Creation and Review Dates

DIF Creation Date: 2010-04-23

Last DIF Revision Date: 2011-03-10

Future DIF Review Date: 2011-04-23

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