Publications
Geomagnetism publications.
Fact Sheets
Fact Sheets
1-2 page plain language summaries of geomagnetism topics and research
Filter Total Items: 415
The Steens Mountain (Oregon) geomagnetic polarity transition: 3. Its regional significance The Steens Mountain (Oregon) geomagnetic polarity transition: 3. Its regional significance
Study of the variations of direction and intensity of the geomagnetic field as recorded by the Miocene lava flows on Steens Mountain, southeastern Oregon, has resulted in a detailed description of total field behavior during a reversal in polarity. In addition to information about the polarity reversal itself, the detailed paleomagnetic record includes several thousand years of...
Authors
E. A. Mankinen, E.E. Larson, C. S. Grommé, M. Prevot, R. S. Coe
By
Current loops fitted to geomagnetic model spherical harmonic coefficients. Current loops fitted to geomagnetic model spherical harmonic coefficients.
One hundred-sixty circular current loops with radial axes were fitted by least squares to the 899 spherical harmonic coefficients of a 29th degree model. In the first case, the parameters that were fitted for each loop were the normalized magnetic moment, the distance from the center of the Earth to the current element, the colatitude and E. longitude of the loop axis, and one-half of...
Authors
L.R. Alldredge
On the interpretation of the geomagnetic energy spectrum On the interpretation of the geomagnetic energy spectrum
Two recent high-degree magnetic energy spectra, based mostly on MAGSAT data, are compared and found to agree very well out to order and degree n = 15, but the spectrum remains somewhat uncertain for higher degrees. The hypothesis that a primary break in the slope of the spectrum, plotted semi-logarithmically, is due to a transition from dominance by core sources to dominance by crustal
Authors
E.R. Benton, L.R. Alldredge
On regional geomagnetic charts On regional geomagnetic charts
When regional geomagnetic charts for areas roughly the size of the United States were compiled by hand, some large local anomalies were displayed in the isomagnetic lines. Since the late nineteen sixties, when the compilation of charts using computers and mathematical models was started, most of the details available in the hand drawn regional charts have been lost. One exception to this...
Authors
L.R. Alldredge
On predicting changes in the geomagnetic field On predicting changes in the geomagnetic field
The present method of using constant secular variation rates to forecast magnetic components at a given site or to forecast spherical harmonic coefficients is known to be inaccurate. A new predictive method using trend and trigonometric functions fitted to known past values is used to extrapolate for a few years into the future. This provides an improvement over the usual linear...
Authors
L.R. Alldredge
Preliminary geomagnetic data, College Observatory, Fairbanks, Alaska, November 1987 Preliminary geomagnetic data, College Observatory, Fairbanks, Alaska, November 1987
No abstract available.
Authors
John B. Townshend, R. V. O’Connell, L.Y. Torrence
Preliminary geomagnetic data, College Observatory, Fairbanks, Alaska, January 1987 Preliminary geomagnetic data, College Observatory, Fairbanks, Alaska, January 1987
No abstract available.
Authors
John B. Townshend, R. V. O’Connell, L.Y. Torrence
Comments on 'Remarks on the secular change in the energy density spectrum of the geomagnetic field' by Joachim Meyer. Comments on 'Remarks on the secular change in the energy density spectrum of the geomagnetic field' by Joachim Meyer.
Meyer has discussed only the Rn aspect of the Alldredge (1984) paper he is criticising. He has ignored the pictorial demonstration of the need for higher harmonics to properly describe the secular variation field than the main field as demonstrated. This more or less independent demonstration supports the general conclusion of that paper.
Authors
L.R. Alldredge
Preliminary geomagnetic data, College Observatory, Fairbanks, Alaska: August 1986 Preliminary geomagnetic data, College Observatory, Fairbanks, Alaska: August 1986
No abstract available.
Authors
John B. Townshend, J.E. Papp, H.K. Rex, L.Y. Torrence
Preliminary geomagnetic data, College Observatory, Fairbanks, Alaska: July 1986 Preliminary geomagnetic data, College Observatory, Fairbanks, Alaska: July 1986
No abstract available.
Authors
John B. Townshend, J.E. Papp, H.K. Rex, L.Y. Torrence
Geophysics: A reversal of geomagnetic polarity Geophysics: A reversal of geomagnetic polarity
The detailed behaviour of the geomagnetic field during reversals is documented by palaeomagnetists to constrain models of the geomagnetic dynamo. Reversals are studied by measuring the magnetic remanence preserved in rocks to obtain both the direction and intensity of the ancient magnetic field.
Authors
Edward A. Mankinen
By
Preliminary geomagnetic data, College Observatory, Fairbanks, Alaska: October 1986 Preliminary geomagnetic data, College Observatory, Fairbanks, Alaska: October 1986
No abstract available.
Authors
John B. Townshend, H.K. Rex, L.Y. Torrence