scholarly journals Toward more reliable long-term indices of geomagnetic activity: Correcting a new inhomogeneity problem in early geomagnetic data

2015 ◽  
Vol 120 (10) ◽  
pp. 8288-8297 ◽  
Author(s):  
L. Holappa ◽  
K. Mursula
Keyword(s):  
Geomagnetic Activity ◽  
Geomagnetic Data ◽  
Inhomogeneity Problem

Long-term variations in the geomagnetic activity level Part II: Ascending phases of sunspot cycles

1994 ◽  
Vol 12 (10/11) ◽  
pp. 1065-1070 ◽  
Author(s):  
V. Mussino ◽  
O. Borello Filisetti ◽  
M. Storini ◽  
H. Nevanlinna
Keyword(s):  
Correlation Coefficient ◽  
Geomagnetic Activity ◽  
Activity Level ◽  
Activity Levels ◽  
Data Set ◽  
The Past ◽  
Long Term Trends ◽  
A Minor ◽  
Long Term Variations

Abstract. Monthly averages of the Helsinki Ak-values have been reduced to the equivalent aa-indices to extend the aa-data set back to 1844. A periodicity of about five cycles was found for the correlation coefficient (r) between geomagnetic indices and sunspot numbers for the ascending phases of sunspot cycles 9 to 22, confirming previous findings based on a minor number of sunspot cycles. The result is useful to researchers in topics related to solar-terrestrial physics, particularly for the interpretation of long-term trends in geomagnetic activity during the past, and to forecast geomagnetic activity levels in the future.

scholarly journals Long-term variations of solar magnetic fields derived from geomagnetic data

2013 ◽  
Vol 53 (7) ◽  
pp. 852-856 ◽  
Author(s):  
K. Georgieva ◽  
B. Kirov ◽  
Yu. A. Nagovitsyn
Keyword(s):  
Magnetic Fields ◽  
Solar Magnetic Fields ◽  
Geomagnetic Data ◽  
Long Term Variations

Long-term variations in the geomagnetic activity level Part II: Ascending phases of sunspot cycles

1994 ◽  
Vol 12 (10) ◽  
pp. 1065 ◽  
Author(s):  
V. Mussino ◽  
O. Borello Filisetti ◽  
M. Storini ◽  
H. Nevanlinna
Keyword(s):  
Geomagnetic Activity ◽  
Activity Level ◽  
Long Term Variations

Long-term variation of the semi-annual wave maxima in geomagnetic activity

1989 ◽  
Vol 33 (4) ◽  
pp. 379-390 ◽  
Author(s):  
Emil M. Apostolov ◽  
Vojtěch Letfus ◽  
J. Pýcha
Keyword(s):  
Geomagnetic Activity ◽  
Term Variation

Reply to comments on the paper “Long term correlation between solar and geomagnetic activity”

2005 ◽  
Vol 67 (14) ◽  
pp. 1375-1376
Author(s):  
E. Echer ◽  
W.D. Gonzalez ◽  
A.L.C. Gonzalez ◽  
A. Prestes ◽  
L.E.A. Vieira ◽  
...  
Keyword(s):  
Geomagnetic Activity
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