@Article{SilvaAESSCPS:2024:EvDBAm,
               author = "Silva, Graziela Belmira Dias da and Alves, Livia Ribeiro and 
                         Espinosa Sarmiento, Karen Viviana and Souza, Vitor Moura Cardoso e 
                         Silva and Silva, Ligia Alves da and Costa, Joaquim Eduardo Rezende 
                         and P{\'a}dua, Marcelo Banik de and S{\'a}nchez Juarez, 
                         Sa{\'u}l Alejandro",
          affiliation = "{Instituto Nacional de Pesquisas Espaciais (INPE)} and {Instituto 
                         Nacional de Pesquisas Espaciais (INPE)} and {Instituto Nacional de 
                         Pesquisas Espaciais (INPE)} and {Instituto Nacional de Pesquisas 
                         Espaciais (INPE)} and {Instituto Nacional de Pesquisas Espaciais 
                         (INPE)} and {Instituto Nacional de Pesquisas Espaciais (INPE)} and 
                         {Instituto Nacional de Pesquisas Espaciais (INPE)} and {Instituto 
                         Nacional de Pesquisas Espaciais (INPE)}",
                title = "Evaluation of dB/dt amplitudes and sources over the Brazilian 
                         region during geomagnetic storms in the 2021–2022 biennium",
              journal = "Journal of Atmospheric and Solar-Terrestrial Physics",
                 year = "2024",
               volume = "258",
                pages = "e106196",
                month = "May",
             keywords = "Ascending phase of solar cycle 25, Ground magnetic field, Low 
                         latitude region, Rate of change (dB/dt).",
             abstract = "The rate of change of the geomagnetic field (dB/dt) observed at 
                         Earth's surface has been used as a proxy of geomagnetically 
                         induced currents, which are known to be hazardous for grounded 
                         technological systems such as high-voltage power grid systems. The 
                         dB/dt rates have been well characterized in the high latitude 
                         region (\≳60°), but much less information is available for 
                         the low latitudes to date. To overcome this limitation, we have 
                         examined dB/dt rates on the H component of the geomagnetic field 
                         as measured by an array of stations operated by the EMBRACE 
                         Magnetometer Network in Brazil. The main focus is to characterize 
                         dB/dt occurrence at very low latitudes (\≲22°) of the 
                         Brazilian peculiar territory, whose magnetic measurements are 
                         influenced by the equatorial electrojet and the presence of the 
                         South Atlantic Magnetic Anomaly (SAMA). The period investigated is 
                         from 2021 to 2022, over the ascending phase of the solar cycle 25. 
                         The statistical analysis demonstrates that dB/dt peak magnitudes 
                         are generally below 0.5 nT/s during magnetic storms, and exhibit a 
                         dependence on the solar cycle for the station near the center of 
                         the SAMA. However, we obtain for a particular case in 2021 that 
                         dB/dt reached 1.35 nT/s in magnitude at the magnetic equator 
                         during daytime, which is a significant value even for higher 
                         latitudes. A case study of the induced geoelectric fields during 
                         this event shows that the conductivity structure beneath two 
                         compared sites plays a major role in the amplitude of such fields 
                         than dB/dt amplitude. Also, the MLT distributions of dB/dt 
                         indicate that ultra-low frequency waves can be a major source of 
                         these signals in lower latitudes.",
                  doi = "10.1016/j.jastp.2024.106196",
                  url = "http://dx.doi.org/10.1016/j.jastp.2024.106196",
                 issn = "1364-6826",
                label = "self-archiving-INPE-MCTIC-GOV-BR",
             language = "en",
           targetfile = "1-s2.0-S1364682624000245-main.pdf",
        urlaccessdate = "15 jun. 2024"
}