@Article{EgitoAndrBati:2016:VeWiMo,
               author = "Egito, F{\'a}bio and Andrioli, V{\^a}nia de F{\'a}tima and 
                         Batista, Paulo Prado",
          affiliation = "{Universidade Federal do Oeste da Bahia (UFOB)} and {Instituto 
                         Nacional de Pesquisas Espaciais (INPE)} and {Instituto Nacional de 
                         Pesquisas Espaciais (INPE)}",
                title = "Vertical winds and momentum fluxes due to equatorial planetary 
                         scale waves using all-sky meteor radar over Brazilian region",
              journal = "Journal of Atmospheric and Solar-Terrestrial Physics",
                 year = "2016",
               volume = "149",
                pages = "108--119",
                month = "Nov.",
             keywords = "Meteor radar, Planetary scale waves, Vertical wind.",
             abstract = "In the equatorial region planetary scale waves play an important 
                         role transporting significant amount of energy and momentum 
                         through atmosphere. Quantifying the momentum transported by these 
                         waves and its effects on the mean flow is rather important. Direct 
                         estimates of the momentum flux transported by waves require 
                         horizontal and vertical wind measurements. Ground-based meteor 
                         radars have provided continuous and reliable measurements of the 
                         horizontal wind components in the Mesosphere and Lower 
                         Thermosphere (MLT) region and have contributed to improve our 
                         knowledge of the dynamics of this region. However, instrumental 
                         limitations hinder its use for measuring vertical winds and 
                         momentum fluxes. On the other hand, according to Babu et al 
                         (2012), all- sky meteor radars are able to infer tridimensional 
                         winds when using a large number of meteor echoes centered at the 
                         meteor ablation peak. Following this approach, we have used 
                         measurements performed by a Meteor Radar installed at S{\~a}o 
                         Jo{\~a}o do Cariri, Brazil (7.4°S; 36.5°W) in order to measure 
                         vertical winds and calculate the momentum flux transported by 
                         equatorial planetary scale waves. In order to evaluate the 
                         accuracy of vertical wind values we have performed several tests 
                         based on a simple model considering real meteor distributions and 
                         theoretical equations for the MLT winds motion. From our tests, we 
                         inferred that Brazilian meteor radar data can be used for this 
                         purpose with an accuracy of ~ 1.8 m/s. The results show that the 
                         vertical wind presents magnitudes of a few meters per second and 
                         occasionally reaches magnitudes around 10 m/s. Below 92 km the 
                         vertical wind is predominantly 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 as well. 
                         Largest wave induced amplitudes in the vertical wind are found in 
                         the 34 d band, reaching up to 4 m/s. From the vertical and zonal 
                         wind measurements, we calculated the vertical transport of zonal 
                         momentum in the 34 d band and found it to be maximum near autumn 
                         equinox, when its value reaches almost 20 m2/s2, while minimum 
                         momentum flux is observed after the winter solstice.",
                  doi = "10.1016/j.jastp.2016.10.005",
                  url = "http://dx.doi.org/10.1016/j.jastp.2016.10.005",
                 issn = "1364-6826",
             language = "en",
           targetfile = "egito_vertical.pdf",
        urlaccessdate = "27 abr. 2024"
}