Evidence for cosmic ray modulation in temperature records from the South Atlantic Magnetic Anomaly region

Abstract

Abstract. Possible direct or indirect climatic effects related to solar variability and El Niño-Southern Oscillation (ENSO) were investigated in the southern Brazil region by means of the annual mean temperatures from four weather stations 2 degrees of latitude apart over the South Atlantic Magnetic Anomaly (SAMA) region. Four maximum temperature peaks are evident at all stations in 1940, 1958, 1977 and 2002. A spectral analysis indicates the occurrence of periodicities between 2 and 7 yr, most likely associated with ENSO, and periodicities of approximately 11 and 22 yr, normally associated with solar variability. Cross-wavelet analysis indicated that the signal associated with the 22 yr solar magnetic cycle was more persistent in the last decades, while the 11 yr sunspot cycle and ENSO periodicities were intermittent. Phase-angle analysis revealed that temperature variations and the 22 yr solar cycle were in anti-phase near the SAMA center. Results show an indirect indication of possible relationships between the variability of galactic cosmic rays and climate change on a regional scale.

Effects of solar activity and galactic cosmic ray cycles on the modulation of the annual average temperature at two sites in southern Brazil

“…For two stations further away, the 22-year cycle was also persistent during the investigated period, but the statistical results indicated a nonlinear relationship between the bidecadal periodicity and temperature variations. In summary, the results of Frigo et al (2013) indicated that a climatic modulation of ∼ 22 years, characteristic of GCRs, was persistent during the last century and was possibly at a maximum in the region closest to the center of the SAMA.…”

“…However, there are few works reporting the possible indirect influence of the geomagnetic field on climatic variations during the last century (e.g., Vieira and da Silva, 2006;Courtillot et al, 2007;Frigo et al, 2013;Campuzano et al, 2016). Frigo et al (2013) investigated the spectral coherence between the 11-and 22-year solar activity cycles and the yearly average temperatures recorded during the last century at four weather stations located in southern Brazil's coastal region. This region showed smaller values of geomagnetic intensity in the 20th century, due to the presence of the South Atlantic Magnetic Anomaly (SAMA).…”

“…The aim of this work is to advance the analyses of Frigo et al (2013) by investigating the connections between temperature variability, solar activity and GCR variations during the last century, including making use of climatological data recorded in other weather stations in southern Brazil. A time series of the solar modulation potential is used as a proxy for GCR variability.…”

The constancy of galactic cosmic rays as recorded by cosmogenic nuclides in iron meteorites

“…Frigo et al. () argued for a possible influence of GCRs on climate on a regional scale and Artamonova and Veretenenko () concluded that GCRs may influence the process of cyclone and anticyclone formation.…”

“…Although there is no consensus on a correlation, some studies have continued to assume a relationship between GCR intensity and cloud cover. Frigo et al (2013) argued for a possible influence of GCRs on climate on a regional scale and Artamonova and Veretenenko (2011) concluded that GCRs may influence the process of cyclone and anticyclone formation. Shaviv (2002Shaviv ( , 2003 proposed that the occurrence of ice-age epochs on the Earth was influenced by the solar system crossing through the spiral-arms of the Milky Way.…”