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@Article{FrigoAnSiLiPaBa:2018:EfSoAc,
               author = "Frigo, Everton and Antonelli, Francesco and Silva, Djeniffer S. S. 
                         da and Lima, Pedro C. M. and Pacca, Igor I. G. and Bageston, 
                         Jos{\'e} Valentin",
          affiliation = "{Universidade Federal do Pampa (UNIPAMPA)} and {Universidade 
                         Federal do Pampa (UNIPAMPA)} and {Universidade Federal do Pampa 
                         (UNIPAMPA)} and {Universidade Federal do Pampa (UNIPAMPA)} and 
                         {Universidade de S{\~a}o Paulo (USP)} and {Instituto Nacional de 
                         Pesquisas Espaciais (INPE)}",
                title = "Effects of solar activity and galactic cosmic ray cycles on the 
                         modulation of the annual average temperature at two sites in 
                         southern Brazil",
              journal = "Annales Geophysicae",
                 year = "2018",
               volume = "36",
               number = "1",
                pages = "555--564",
                month = "Apr.",
             keywords = "Meteorology and atmospheric dynamics, climatology.",
             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 similar to 26 degrees. 
                         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 similar to 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 degrees S but at different longitudes. The first of 
                         these stations (Torres - TOR) is located in the coastal region, 
                         and the other (Irai - 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.",
                  doi = "10.5194/angeo-36-555-2018",
                  url = "http://dx.doi.org/10.5194/angeo-36-555-2018",
                 issn = "0992-7689",
             language = "en",
           targetfile = "frigo_effects.pdf",
        urlaccessdate = "27 nov. 2020"
}


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