Geophysical Institute of the ASCR

Geomagnetic forcing on regional and global temperatures
We show that inter-annual variations of temperature in Europe, North America and over the globe at
a time of faster warming of the earth’s surface over the past thirty years are influenced by
geomagnetic activity indicating the solar wind (Bucha, 2004, 2005). The obtained results help to
distinguish between the response to geomagnetic and anthropogenic forcing and contribute to useful
climate forecasts in Europe and North America up to six months in advance.
High correlation coefficients that were found between geomagnetic activity and meteorological
parameters are important for the detection of causes influencing inter-annual and intra-seasonal
variations of regional and global temperatures in the past several decades (Bucha and Bucha, 1998,
2002). The positive phase of NAO (North Atlantic Oscillation) prevailed from 1973 to 1994. At that
time also geomagnetic activity was highest over the past 135 years. We found that the NAO as well as
winter temperatures in Europe and in the U.S.A. are positively correlated with geomagnetic activity.
Summer temperatures in Europe are also positively correlated (correlation coefficient equals 0.78)
while temperatures in the USA are negatively correlated (-0.77) with geomagnetic activity (Bucha,
2005).
aa
50
30
10 64
T(°C)
60
56
a
b
aa
T(°C)
120
100
80
60 65
40
108
104
100 0.4
∆T(°C)
60
T(°C)
55
0.2
0.0
-0.2
c
d
e
f
1970 1980 1990 2000
years
Fig. 38. Time series of (a) geomagnetic activity (aa index) for February, (b) surface air temperature in Europe
for the sum of June-August, (c) geomagnetic activity for the sum of December – February, (d) surface air
temperature in the U.S.A. for the sum of May – July and (e) for the sum of May – September, (f) annual
anomalies of global temperature.
Successful seasonal forecasts up to six months in advance for Europe and the USA could become
a good evidence of the validity of evolutionary processes in the atmosphere influenced by
geomagnetic forcing. Preliminary predictions based on the positive correlation between geomagnetic
activity (Fig. 38, curve a) and summer temperature in Europe indicate that low geomagnetic activity
in February 2005 influenced the temperature in central Europe which was below normal in summer
2005 with probability of 70 – 80% (curve b). Vice versa, negative correlation between geomagnetic
activity in winter (curve c) and summer temperature in the USA (curve d) shows that the US
temperature in summer 2005 probably was higher than was in 2004.
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