author = "Goncharenko, Larisa P. and Zhang, Shunrong and Liu, Huixin and 
                         Tsugawa, Takuya and Batista, Inez Staciarini and Reinisch, Bodo 
          affiliation = "{MIT Haystack Observatory} and {MIT Haystack Observatory} and 
                         {Kyushu University} and NICT and {Instituto Nacional de Pesquisas 
                         Espaciais (INPE)} and {Lowell Digisonde International}",
                title = "Longitudinal differences in the low-latitude ionosphere and in the 
                         ionospheric variability",
            booktitle = "Proceedings...",
                 year = "2017",
         organization = "AGU Fall Meeting",
             abstract = "Analysis of longitudinal differences in ionospheric parameters can 
                         illuminate variety of mechanisms responsible for ionospheric 
                         variability. In this study, we aim to 1) quantitatively describe 
                         major features of longitudinal differences in peak electron 
                         density in the low-latitude ionosphere; 2) examine differences in 
                         ionospheric variability at different longitude sectors, and 3) 
                         illustrate longitudinal differences in ionospheric response to a 
                         large disturbance event, sudden stratospheric warming of 2016. We 
                         examine NmF2 observations by a network of ionosondes in the 
                         American (30-80W) and Asian (110-170E) longitudinal sectors. 
                         Selected instruments are located in the vicinity of EIA troughs 
                         (Jicamarca, Sao Luis, Guam, Kwajalein), northern and southern 
                         crests of EIA (Boa Vista, Tucuman, Cachoeira Paulista, Okinawa), 
                         and beyond EIA crests (Ramey, Yamagawa, Kokubunji). To examine 
                         main ionospheric features at each location, we use long-term 
                         datasets collected at each site to construct empirical models that 
                         describe variations in NmF2 as a function of local time, season, 
                         solar flux, and geomagnetic activity. This set of empirical models 
                         can be used to accurately describe background ionospheric behavior 
                         and serve as a set of observational benchmarks for global 
                         circulation models. It reveals, for example, higher NmF2 in the 
                         EIA trough in the Asian sector as compared to the American sector. 
                         Further, we quantitatively describe variability in NmF2 as a 
                         difference between local observations and local empirical model, 
                         and find that American sectors EIA trough has overall higher 
                         variability that maximizes for all local times during wintertime, 
                         while Asian sector trough variability does not change 
                         significantly with season. Additionally, local empirical models 
                         are used to isolate ionospheric features resulting from dynamical 
                         disturbances of different origin (e.g. geomagnetic storms, 
                         convective activity, sudden stratospheric warming events, etc.). 
                         We illustrate this approach with the case of sudden stratospheric 
                         warming of 2016.",
  conference-location = "New Orleans",
      conference-year = "11-15 Dec.",
             language = "en",
           targetfile = "goncharenko_longitudinal.pdf",
        urlaccessdate = "2021, Apr. 20"