Geomagnetism and paleomagnetism

2011 ◽  
Keyword(s):  
Geomagnetism And Paleomagnetism

scholarly journals Comparison of <i>H</i> component geomagnetic field time series obtained at different sites over South America

2018 ◽  
Vol 36 (3) ◽  
pp. 937-943 ◽  
Author(s):  
Maurício J. A. Bolzan ◽  
Clezio M. Denardini ◽  
Alexandre Tardelli
Keyword(s):  
South America ◽  
Geomagnetic Field ◽  
Phase Coherence ◽  
South American ◽  
Data Set ◽  
Geomagnetism And Paleomagnetism ◽  
Strong Phase ◽  
Geomagnetic Fields ◽  
Time Variations ◽  
Physical Phenomena

Abstract. The geomagnetic field in the Brazilian sector is influenced by the South American Magnetic Anomaly (SAMA) that causes a decrease in the magnitude of the local geomagnetic field when compared to other regions in the world. Thus, the magnetometer network and data set of space weather over Brazil led by Embrace are important tools for promoting the understanding of geomagnetic fields over Brazil. In this sense, in this work we used the H component of geomagnetic fields obtained at different sites in South America in order to compare results from the phase coherence obtained from wavelet transform (WT). Results from comparison between Cachoeira Paulista (CXP) and Eusébio (EUS), and Cachoeira Paulista and São Luis (SLZ), indicated that there exist some phenomena that occur simultaneously in both locations, putting them in the same phase coherence. However, there are other phenomena putting both locations in a strong phase difference as observed between CXP and Rio Grande, Argentina (RGA). This study was done for a specific moderate geomagnetic storm that occurred in March 2003. The results are explained in terms of nonlinear interaction between physical phenomena acting in distinct geographic locations and at different times and scales. Keywords. Geomagnetism and paleomagnetism (time variations – diurnal to secular)

U.S.G.S. SURVEY

Geophysics ◽  
1976 ◽  
Vol 41 (3) ◽  
pp. 553-553
Keyword(s):  
Magnetic Measurements ◽  
Geological Survey ◽  
Total Response ◽  
Detailed Report ◽  
Geomagnetism And Paleomagnetism ◽  
Mailing Lists ◽  
Goddard Space Flight Center ◽  
American Geophysical ◽  
Low Altitude ◽  
The U.S

During 1975, the U.S. Geological Survey, on behalf of Goddard Space Flight Center (National Aeronautics and Space Administration), conducted a survey of potential users of low‐altitude satellite magnetic measurements for solid‐earth geophysical and geologic studies. In May, 8900 letters and questionnaires were mailed out. This included 6000 addresses from the Society of Exploration Geophysicists’ domestic mailing list and 2900 mailings to the American Geophysical Union’s Geomagnetism and Paleomagnetism Section membership. By conservative estimate, there is at least a 10 percent overlap between these two mailing lists. As of September 1, we had received 2448 responses. This represents approximately 28 percent of the total number of questionnaires sent out. A summary questionnaire including the tabulated responses is shown in Table 1. The total response to each question does not always equal 2448 because no responses were given to some questions and more than one response to others. In addition to replies from individual scientists, there were several corporate responses. A detailed report summarizing the results of the survey is available from Robert D. Regan. U.S. Geological Survey, National Center (906), Reston, Va. 22092.

scholarly journals Reconstructing the long-term cosmic ray intensity: linear relations do not work

2003 ◽  
Vol 21 (4) ◽  
pp. 863-867 ◽  
Author(s):  
K. Mursula ◽  
I. G. Usoskin ◽  
G. A. Kovaltsov
Keyword(s):  
Cosmic Ray ◽  
Geomagnetism And Paleomagnetism ◽  
Cosmic Ray Intensity ◽  
Linear Relations ◽  
Cosmic Ray Modulation ◽  
Interplanetary Physics ◽  
Long Time ◽  
Time Variations ◽  
Cosmic Ray Flux

Abstract. It was recently suggested (Lockwood, 2001) that the cosmic ray intensity in the neutron monitor energy range is linearly related to the coronal source flux, and can be reconstructed for the last 130 years using the long-term coronal flux estimated earlier. Moreover, Lockwood (2001) reconstructed the coronal flux for the last 500 years using a similar linear relation between the flux and the concentration of cosmogenic 10 Be isotopes in polar ice. Here we show that the applied linear relations are oversimplified and lead to unphysical results on long time scales. In particular, the cosmic ray intensity reconstructed by Lockwood (2001) for the last 130 years has a steep trend which is considerably larger than the trend estimated from observations during the last 65 years. Accordingly, the reconstructed cosmic ray intensity reaches or even exceeds the local interstellar cosmic ray flux around 1900. We argue that these unphysical results obtained when using linear relations are due to the oversimplified approach which does not take into account the complex and essentially nonlinear nature of long-term cosmic ray modulation in the heliosphere. We also compare the long-term cosmic ray intensity based on a linear treatment with the reconstruction based on a recent physical model which predicts a considerably lower cosmic ray intensity around 1900.Key words. Interplanetary physics (cosmic rays; heliopause and solar wind termination) – Geomagnetism and paleomagnetism (time variations, secular and long-term)

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