author = "Barros, Figueiredo Cosme Alexandre Oliveira and Buriti, Ricardo A. 
                         and Paulino, Igo and Meriwether, John W. and Makela, Jonathan J. 
                         and Batista, Inez Staciarini and Barros, Diego and Medeiros, 
                         Amauri F.",
          affiliation = "{Instituto Nacional de Pesquisas Espaciais (INPE)} and 
                         {Universidade Federal de Campina Grande (UFCG)} and {Universidade 
                         Federal de Campina Grande (UFCG)} and {Clemson University} and 
                         {University of Illinois at Urbana-Champaign} and {Instituto 
                         Nacional de Pesquisas Espaciais (INPE)} and {Instituto Nacional de 
                         Pesquisas Espaciais (INPE)} and {Universidade Federal de Campina 
                         Grande (UFCG)}",
                title = "Effects of the midnight temperature maximum observed in the 
                         thermosphere-ionosphere over the northeast of Brazil",
              journal = "Annales Geophysicae",
                 year = "2017",
               volume = "35",
               number = "4",
                pages = "953--963",
                month = "Aug.",
             keywords = "Ionosphere, equatorial ionosphere, ionosphere-atmosphere 
                         interactions, meteorology and atmospheric dynamics, thermospheric 
             abstract = "The midnight temperature maximum (MTM) has been observed in the 
                         lower thermosphere by two Fabry-Perot interferometers (FPIs) at 
                         Sao Joao do Cariri (7.4 degrees S, 36.5 degrees W) and Cajazeiras 
                         (6.9 degrees S, 38.6 degrees W) during 2011, when the solar 
                         activity was moderate and the solar flux was between 90 and 155 
                         SFU (1 SFU = 10(-22) W m(-2) Hz(-1)). The MTM is studied in detail 
                         using measurements of neutral temperature, wind and airglow 
                         relative intensity of OI630.0 nm (referred to as OI6300), and 
                         ionospheric parameters, such as virtual height (h'F), the peak 
                         height of the F2 region (hmF2), and critical frequency of the F 
                         region (foF2), which were measured by a Digisonde instrument (DPS) 
                         at Eusebio (3.9 degrees S, 38.4 degrees W; geomagnetic coordinates 
                         7.31 degrees S, 32.40 degrees E for 2011). The MTM peak was 
                         observed mostly along the year, except in May, June, and August. 
                         The amplitudes of the MTM varied from 64 +/- 46K in April up to 
                         144 +/- 48K in October. The monthly temperature average showed a 
                         phase shift in the MTM peak around 0.25 h in September to 2.5 h in 
                         December before midnight. On the other hand, in February, March, 
                         and April the MTM peak occurred around midnight. International 
                         Reference Ionosphere 2012 (IRI-2012) model was compared to the 
                         neutral temperature observations and the IRI-2012 model failed in 
                         reproducing the MTM peaks. The zonal component of neutral wind 
                         flowed eastward the whole night; regardless of the month and the 
                         magnitude of the zonal wind, it was typically within the range of 
                         50 to 150 m s(-1) during the early evening. The meridional 
                         component of the neutral wind changed its direction over the 
                         months: from November to February, the meridional wind in the 
                         early evening flowed equatorward with a magnitude between 25 and 
                         100 m s(-1); in contrast, during the winter months, the meridional 
                         wind flowed to the pole within the range of 0 to 50 m s(-1). Our 
                         results indicate that the reversal (changes in equator to poleward 
                         flow) or abatement of the meridional winds is an important factor 
                         in the MTM generation. From February to April and from September 
                         to December, the h'F and the hmF2 showed an increase around 
                         18:00-20:00 LT within a range between 300 and 550 km and reached a 
                         minimal height of about 200-300 km close to midnight; then the 
                         layer rose again by about 40 km or, sometimes, remained at 
                         constant height. Furthermore, during the winter months, the h'F 
                         and hmF2 showed a different behavior; the signature of the 
                         pre-reversal enhancement did not appear as in other months and the 
                         heights did not exceed 260 and 350 km. Our observation indicated 
                         that the midnight collapse of the F region was a consequence of 
                         the MTM in the meridional wind that was reflected in the height of 
                         the F region. Lastly, the behavior of the OI6300 showed, from 
                         February to April and from September to December, an increase in 
                         intensity around midnight or 1 h before, which was associated with 
                         the MTM, whereas, from May to August, the relative intensity was 
                         more intense in the early evening and decayed during the night.",
                  doi = "10.5194/angeo-35-953-2017",
                  url = "http://dx.doi.org/10.5194/angeo-35-953-2017",
                 issn = "0992-7689",
             language = "en",
           targetfile = "figueiredo_effects.pdf",
        urlaccessdate = "04 dez. 2020"