author = "Andrioli, V{\^a}nia F{\'a}tima and Batista, Paulo Prado and 
                         Clemesha, Barclay Robert and Schuch, Nelson Jorge and Buriti, R. 
          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 {Universidade Federal de Campina Grande 
                title = "Multi-year observations of gravity wave momentum fluxes at low and 
                         middle latitudes inferred by all-sky meteor radar",
              journal = "Annales Geophysicae",
                 year = "2015",
               volume = "33",
               number = "9",
                pages = "1183--1193",
                month = "Sept.",
             keywords = "Meteorology and atmospheric dynamics (middle atmosphere 
             abstract = "We have applied a modified composite day analysis to the Hocking 
                         (2005) technique to study gravity wave (GW) momentum fluxes in the 
                         mesosphere and lower thermosphere (MLT). Wind measurements from 
                         almost continuous meteor radar observations during June 
                         2004-December 2008 over S{\~a}o Jo{\~a}o do Cariri (Cariri; 7 
                         S, 36 W), April 1999-November 2008 over Cachoeira Paulista (CP; 
                         23 S, 45 W), and February 2005-December 2009 over Santa Maria 
                         (SM; 30 S, 54 W) were used to estimate the GW momentum fluxes 
                         and variances in the MLT region. Our analysis can provide monthly 
                         mean altitude profiles of vertical fluxes of horizontal momentum 
                         for short-period (less than 2-3 h) GWs. The averages for each 
                         month throughout the entire data series have shown different 
                         behavior for the momentum fluxes depending on latitude and 
                         component. The meridional component has almost the same behavior 
                         at the three sites, being positive (northward), for most part of 
                         the year. On the other hand, the zonal component shows different 
                         behavior at each location: it is positive for almost half the year 
                         at Cariri and SM but predominantly negative over CP. Annual 
                         variation in the GW momentum fluxes is present at all sites in the 
                         zonal component and also in SM at 89 km in the meridional 
                         component. The seasonal analysis has also shown a 4-month 
                         oscillation at 92.5 km over SM in the zonal component and over CP 
                         at the same altitudes but for the meridional component.",
                  doi = "10.5194/angeo-33-1183-2015",
                  url = "http://dx.doi.org/10.5194/angeo-33-1183-2015",
                 issn = "0992-7689",
             language = "en",
        urlaccessdate = "03 dez. 2020"