Intertropical Convergence Zone as the Possible Source Mechanism for Southward Propagating Medium-Scale Traveling Ionospheric Disturbances over South American Low-Latitude and Equatorial Region
Patrick Essien,
Cosme Alexandre Oliveira Barros Figueiredo,
Hisao Takahashi,
Nana Ama Browne Klutse,
Cristiano Max Wrasse,
João Maria de Sousa Afonso,
David Pareja Quispe,
Solomon Otoo Lomotey,
Tunde Toyese Ayorinde,
José H. A. Sobral,
Moses Jojo Eghan,
Samuel Sanko Sackey,
Diego Barros,
Anderson V. Bilibio,
Francis Nkrumah,
Kwesi Akumenyi Quagraine
Affiliations
Patrick Essien
Meteorology and Atmospheric Research Lab, Department of Physics, School of Physical Sciences, College of Agriculture and Natural Sciences, University of Cape Coast, Cape Coast PMB TF0494, Ghana
Cosme Alexandre Oliveira Barros Figueiredo
Space Weather Division, National Institute for Space Research (INPE), Av. dos Astronautas, Sao Jose dos Campos 12227-010, SP, Brazil
Hisao Takahashi
Space Weather Division, National Institute for Space Research (INPE), Av. dos Astronautas, Sao Jose dos Campos 12227-010, SP, Brazil
Nana Ama Browne Klutse
Climate Change Science, African Institute for Mathematical Sciences (AIMS) Rwanda, Kigali 20093, Rwanda
Cristiano Max Wrasse
Space Weather Division, National Institute for Space Research (INPE), Av. dos Astronautas, Sao Jose dos Campos 12227-010, SP, Brazil
João Maria de Sousa Afonso
National Institute of Meteorology and Geophysics of Angola (INAMET), 21 de Janeiro Street, Morro Bento Neighborhood, Luanda, Angola
David Pareja Quispe
Departamento de Física Interdisciplinaria, Facultad de Ciencias Físicas, Universidad Nacional Mayor de San Marcos (UNMSM), Av. Carlos Germán Amezaga, No. 375, Cercado de Lima 15081, Peru
Solomon Otoo Lomotey
Space Weather Division, National Institute for Space Research (INPE), Av. dos Astronautas, Sao Jose dos Campos 12227-010, SP, Brazil
Tunde Toyese Ayorinde
Space Weather Division, National Institute for Space Research (INPE), Av. dos Astronautas, Sao Jose dos Campos 12227-010, SP, Brazil
José H. A. Sobral
Space Weather Division, National Institute for Space Research (INPE), Av. dos Astronautas, Sao Jose dos Campos 12227-010, SP, Brazil
Moses Jojo Eghan
Meteorology and Atmospheric Research Lab, Department of Physics, School of Physical Sciences, College of Agriculture and Natural Sciences, University of Cape Coast, Cape Coast PMB TF0494, Ghana
Samuel Sanko Sackey
Meteorology and Atmospheric Research Lab, Department of Physics, School of Physical Sciences, College of Agriculture and Natural Sciences, University of Cape Coast, Cape Coast PMB TF0494, Ghana
Diego Barros
Space Weather Division, National Institute for Space Research (INPE), Av. dos Astronautas, Sao Jose dos Campos 12227-010, SP, Brazil
Anderson V. Bilibio
Space Weather Division, National Institute for Space Research (INPE), Av. dos Astronautas, Sao Jose dos Campos 12227-010, SP, Brazil
Francis Nkrumah
Meteorology and Atmospheric Research Lab, Department of Physics, School of Physical Sciences, College of Agriculture and Natural Sciences, University of Cape Coast, Cape Coast PMB TF0494, Ghana
Kwesi Akumenyi Quagraine
Meteorology and Atmospheric Research Lab, Department of Physics, School of Physical Sciences, College of Agriculture and Natural Sciences, University of Cape Coast, Cape Coast PMB TF0494, Ghana
This paper presents the Intertropical Convergence Zone (ITCZ) as the possible source mechanism of the medium-scale traveling ionospheric disturbances (MSTIDs) propagating to the southeast direction over the South American region. Using the data collected by the GNSS dual-frequency receivers network from January 2014 to December 2019, detrended TEC maps were generated to identify and characterize 144 MSTIDs propagating southeastward over the South American low-latitude and equatorial region. We also used images from the Geostationary Operational Environmental Satellite (GOES) 13 and 16 in the infrared (IR) and water vapor (WV) channel, and reanalisys data from the National Centers for Environmental Prediction (NCEP) of the National Oceanic and Atmospheric Administration (NOAA) to study the daily features and seasonal migration of ITCZ. In the winter, when ITCZ migrates to the northern hemisphere around 10–15° N, 20 MSTIDs propagated southeastward. During summer, when the ITCZ lies within the continent, around 0–5° S 80 MSTIDs were observed to propagate southeastward; in the equinoxes (spring and fall), 44 MSTIDs were observed. Again, the MSTIDs propagating southeastward showed a clear seasonality of their local time dependence; in summer, the MSTIDs occurred frequently in the evening hours, whereas those in winter occurred during the daytime. We also found for the first time that the day-to-day observation of ITCZ position and MSTIDs propagation directions were consistent. With regard to these new findings, we report that the MSTIDs propagating southeastward over the South American region are possibly induced by the atmospheric gravity waves, which are proposed as being generated by the ITCZ in the troposphere. The mean distribution of the horizontal wavelength, period, and phase velocity are 698 ± 124 km, 38 ± 8 min, and 299 ± 89 m s−1, respectively. For the first time, we were able to use MSTID propagation directions as a proxy to study the source region.
