author = "Braga, Carlos Roberto and Vourlidas, Angelos and Stenborg, 
                         Guillermo and Dal Lago, Alisson and Mendon{\c{c}}a, Rafael 
                         Rodrigues Souza de and Echer, Ezequiel",
          affiliation = "{George Mason University} and {The Johns Hopkins University 
                         Applied Physics Laboratory} and {U.S. Naval Research Laboratory} 
                         and {Instituto Nacional de Pesquisas Espaciais (INPE)} and 
                         {Instituto Nacional de Pesquisas Espaciais (INPE)} and {Instituto 
                         Nacional de Pesquisas Espaciais (INPE)}",
                title = "Predicting the time of arrival of coronal mass ejections at Earth 
                         from heliospheric imaging observations",
              journal = "Journal of Geophysical Research: Space Physics",
                 year = "2020",
               volume = "125",
               number = "9",
                pages = "e2020JA027885",
                month = "Sept.",
             abstract = "The time of arrival (ToA) of coronal mass ejections (CMEs) at 
                         Earth is a key parameter due to the space weather phenomena 
                         associated with the CME arrival, such as intense geomagnetic 
                         storms. Despite the incremental use of new instrumentation and the 
                         development of novel methodologies, ToA estimated errors remain 
                         above 10 h on average. Here, we investigate the prediction of the 
                         ToA of CMEs using observations from heliospheric imagers, i.e., 
                         from heliocentric distances higher than those covered by the 
                         existent coronagraphs. In order to perform this work, we analyze 
                         14 CMEs observed by the heliospheric imagers HI\‐1 onboard 
                         the twin STEREO spacecraft to determine their front location and 
                         speed. The kinematic parameters are derived with a new technique 
                         based on the Elliptical Conversion (ElCon) method, which uses 
                         simultaneous observations from the two viewpoints from STEREO. 
                         Outside the field of view of the instruments, we assume that the 
                         dynamics of the CME evolution is controlled by aerodynamic drag, 
                         i.e., a force resulting from the interaction with particles from 
                         the background solar wind. To model the drag force, we use a 
                         physical model that allows us to derive its parameters without the 
                         need to rely on drag coefficients derived empirically. We found a 
                         CME ToA mean error of 1.6  8.0 h ToA and a mean absolute error of 
                         6.9  3.9 h for a set of 14 events. The results suggest that 
                         observations from HI\‐1 lead to estimates with similar 
                         errors to observations from coronagraphs.",
                  doi = "10.1029/2020JA027885",
                  url = "http://dx.doi.org/10.1029/2020JA027885",
                 issn = "2169-9402",
             language = "en",
           targetfile = "braga_predicting.pdf",
        urlaccessdate = "19 abr. 2021"