Solar modulation of galactic cosmic rays during the last five solar cycles

2008 ◽  
Vol 70 (1) ◽  
pp. 169-183 ◽  
Author(s):  
M. Singh ◽  
Y.P. Singh ◽  
Badruddin
New Astronomy ◽  
2011 ◽  
Vol 16 (7) ◽  
pp. 430-438 ◽  
Author(s):  
Partha Chowdhury ◽  
B.N. Dwivedi ◽  
P.C. Ray

2013 ◽  
Vol 409 ◽  
pp. 012194
Author(s):  
M A Bzheumikhova ◽  
O Adriani ◽  
G C Barbarino ◽  
G A Bazilevskaya ◽  
R Bellotti ◽  
...  

2017 ◽  
Vol 798 ◽  
pp. 012042
Author(s):  
A G Mayorov ◽  
O Adriani ◽  
S Y Aleksandrin ◽  
G C Barbarino ◽  
G A Bazilevskaya ◽  
...  

2018 ◽  
Vol 36 (2) ◽  
pp. 555-564 ◽  
Author(s):  
Everton Frigo ◽  
Francesco Antonelli ◽  
Djeniffer S. S. da Silva ◽  
Pedro C. M. Lima ◽  
Igor I. G. Pacca ◽  
...  

Abstract. Quasi-periodic variations in solar activity and galactic cosmic rays (GCRs) on decadal and bidecadal timescales have been suggested as a climate forcing mechanism for many regions on Earth. One of these regions is southern Brazil, where the lowest values during the last century were observed for the total geomagnetic field intensity at the Earth's surface. These low values are due to the passage of the center of the South Atlantic Magnetic Anomaly (SAMA), which crosses the Brazilian territory from east to west following a latitude of ∼ 26∘. In areas with low geomagnetic intensity, such as the SAMA, the incidence of GCRs is increased. Consequently, possible climatic effects related to the GCRs tend to be maximized in this region. In this work, we investigate the relationship between the ∼ 11-year and ∼ 22-year cycles that are related to solar activity and GCRs and the annual average temperature recorded between 1936 and 2014 at two weather stations, both located near a latitude of 26∘ S but at different longitudes. The first of these stations (Torres – TOR) is located in the coastal region, and the other (Iraí – IRA) is located in the interior, around 450 km from the Atlantic Ocean. Sunspot data and the solar modulation potential for cosmic rays were used as proxies for the solar activity and the GCRs, respectively. Our investigation of the influence of decadal and bidecadal cycles in temperature data was carried out using the wavelet transform coherence (WTC) spectrum. The results indicate that periodicities of 11 years may have continuously modulated the climate at TOR via a nonlinear mechanism, while at IRA, the effects of this 11-year modulation period were intermittent. Four temperature maxima, separated by around 20 years, were detected in the same years at both weather stations. These temperature maxima are almost coincident with the maxima of the odd solar cycles. Furthermore, these maxima occur after transitions from even to odd solar cycles, that is, after some years of intense GCR flux. The obtained results offer indirect mathematical evidence that solar activity and GCR variations contributed to climatic changes in southern Brazil during the last century. A comparison of the results obtained for the two weather stations indicates that the SAMA also contributes indirectly to these temperature variations. The contribution of other mechanisms also related to solar activity cannot be excluded. Keywords. Meteorology and atmospheric dynamics (climatology)


1981 ◽  
Vol 249 ◽  
pp. L71 ◽  
Author(s):  
F. B. McDonald ◽  
J. H. Trainor ◽  
N. Lal ◽  
M. A. I. van Hollebeke ◽  
W. R. Webber

1994 ◽  
Vol 11 (2) ◽  
pp. 170-174 ◽  
Author(s):  
D. L. Hall ◽  
J. E. Humble ◽  
M. L. Duldig

AbstractWe have deduced the yearly averaged value of the solar diurnal variation as observed by a surface muon telescope and three underground muon telescopes over the years 1957 to 1985. This has allowed us to examine the temporal variation in both the latitudinal gradient Gz and the product of the parallel mean free path and the radial gradient of galactic cosmic rays during three consecutive solar cycles. The median rigidities of the primary particles being detected by the telescopes are 50 GV in the case of the surface muon telescope and greater than 150 GV in the case of the underground muon telescopes. We have compared our results with those of a similar study made from observations of the solar diurnal variation by neutron monitors and an ion chamber, which have median rigidities of response between 17 and 70 GV (Bieber and Chen 1991a). The product has a solar magnetic cycle dependence and our values are lower than those observed by neutron monitors, in agreement with the Bieber and Chen observation that reverses after a solar magnetic field reversal, in accordance with drift theories.


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