author = "Egito, F{\'a}bio and Batista, Paulo Prado and Clemesha, Barclay 
                         Robert and Buriti, Ricardo A.",
          affiliation = "{Universidade Federal do Oeste da Bahia (UFOB)} and {Instituto 
                         Nacional de Pesquisas Espaciais (INPE)} and {Instituto Nacional de 
                         Pesquisas Espaciais (INPE)} and {Universidade Federal de Campina 
                         Grande (UFCG)}",
                title = "Vertical winds and 3-4 day momentum flux in the MLT inferred from 
                         meteor radar measurements",
                 year = "2015",
         organization = "International Congress of the Brazilian Geophysical Society, 14.",
             abstract = "Planetary scale waves in equatorial region transport a significant 
                         amount of energy and momentum through atmosphere. Quantifying the 
                         momentum transported by these waves and its effects toward the 
                         mean flow is rather important. Direct estimative of the momentum 
                         flux transported by these waves requires horizontal and vertical 
                         wind measurements. Ground-based meteor radars have provided 
                         continuous and reliable measurements of the horizontal wind 
                         components in the MLT region. On the other hand, vertical wind 
                         component does not present the same reliability. However, an 
                         approach presented by Babu et al. (2012), made possible to 
                         calculate tridimensional daily winds by using only near zenith 
                         echoes detected around their maximum counting rate, i.e., during 
                         early morning hours. From daily tridimensional winds, momentum 
                         fluxes due to planetary scale waves can be estimated. Following 
                         this approach, we have used measurements performed by a meteor 
                         radar installed at S{\~a}o Jo{\~a}o do Cariri (7.4S; 36.5W) in 
                         order to measure vertical winds and after determine the momentum 
                         flux transported by these waves. Vertical wind presents magnitudes 
                         of a few meters per second and occasionally reaches magnitudes 
                         higher than 10 m/s. Below 92 km vertical wind is upward during the 
                         whole year and above exhibits a semi-annual oscillation with 
                         downward phase during the equinoxes. Variations associated to 
                         planetary scale waves in the vertical wind are also observed and 
                         some of them appear simultaneously in the zonal and meridional 
                         wind. Vertical transport of zonal momentum fluxes of 3-4 day 
                         component is found to be maximum near autumn equinox, when its 
                         value reaches almost 20 m2s -2, while minimum momentum fluxes were 
                         observed before winter solstice.",
  conference-location = "Rio de Janeiro, RJ",
      conference-year = "3-6 Aug.",
        urlaccessdate = "25 jan. 2021"