Long-Term Study on Medium-Scale Traveling Ionospheric Disturbances Observed over the South American Equatorial Region
Using data collected by the GNSS dual-frequency receivers network, de-trended TEC maps were generated to identify and characterize the medium-scale traveling ionospheric disturbances (MSTIDs) over the South American equatorial region (latitude: <inline-formula><math xmlns="http://www.w...
| Main Authors: | , , , , , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2021-10-01
|
| Series: | Atmosphere |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2073-4433/12/11/1409 |
| _version_ | 1797511195175944192 |
|---|---|
| author | Patrick Essien Cosme Alexandre Oliveira Barros Figueiredo Hisao Takahashi Cristiano Max Wrasse Diego Barros Nana Ama Browne Klutse Solomon Otoo Lomotey Toyese Tunde Ayorinde Delano Gobbi Anderson V. Bilibio |
| author_facet | Patrick Essien Cosme Alexandre Oliveira Barros Figueiredo Hisao Takahashi Cristiano Max Wrasse Diego Barros Nana Ama Browne Klutse Solomon Otoo Lomotey Toyese Tunde Ayorinde Delano Gobbi Anderson V. Bilibio |
| author_sort | Patrick Essien |
| collection | DOAJ |
| description | Using data collected by the GNSS dual-frequency receivers network, de-trended TEC maps were generated to identify and characterize the medium-scale traveling ionospheric disturbances (MSTIDs) over the South American equatorial region (latitude: <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mn>0</mn><mo>∘</mo></msup></semantics></math></inline-formula> to <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mn>15</mn><mo>∘</mo></msup></semantics></math></inline-formula> S and longitude: <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mn>30</mn><mo>∘</mo></msup></semantics></math></inline-formula> to <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mn>55</mn><mo>∘</mo></msup></semantics></math></inline-formula> W) during solar cycle 24 (from January 2014 to December 2019). A total of 712 MSTIDs were observed during quiet geomagnetic conditions. The Frequency of occurrence of MSTID is high during the solar maximum and low in the minimum phase. This might be due to the solar cycle dependence of gravity wave activity in the lower atmosphere and gravity wave propagation conditions in the thermosphere. The predominant daytime MSTIDs, representing 80% of the total observations, occurred in winter (June-August season in the southern hemisphere) with the secondary peak in the equinox; while the evening time MSTIDs, representing 18% of the entire events, occurred in summer (December to February season) and equinox (March to May and September to November), and the remaining 2% of the MSTIDs were observed during nighttime. The seasonal variation of the MSTID events was attributed to the source mechanisms generating them, the wind filtering and dissipation effects, and the local time dependency. The horizontal wavelengths of the MSTIDs were mostly concentrated between 500 and 800 km, with the mean value of 667 ± 131 km. The observed periods ranged from 30 to 45 min with the mean value of 36 ± 7 min. The observed horizontal phase speeds were distributed around 200 to 400 m/s, with the corresponding mean of 301 ± 75 m/s. The MSTIDs in the winter solstice and equinoctial months preferentially propagated northeastward and northwestward. Meanwhile, during the summer solstice, they propagated in all directions. The anisotropy of the propagation direction might be due to several reasons: the wind and dissipative filtering effects, ion drag effects, the primary source region, and the presence of the secondary or tertiary gravity waves in the thermosphere. Atmospheric gravity waves from strong convective sources might be the primary precursor for the observed equatorial MSTIDs. In all seasons, we noted that the MSTIDs propagating southeastward were probably excited by the likely gravity waves generated by the intertropical convergence zone (ITCZ). |
| first_indexed | 2024-03-10T05:43:00Z |
| format | Article |
| id | doaj.art-2c71fabf067b4c51811378b2b7ce9399 |
| institution | Directory Open Access Journal |
| issn | 2073-4433 |
| language | English |
| last_indexed | 2024-03-10T05:43:00Z |
| publishDate | 2021-10-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Atmosphere |
| spelling | doaj.art-2c71fabf067b4c51811378b2b7ce93992023-11-22T22:23:56ZengMDPI AGAtmosphere2073-44332021-10-011211140910.3390/atmos12111409Long-Term Study on Medium-Scale Traveling Ionospheric Disturbances Observed over the South American Equatorial RegionPatrick Essien0Cosme Alexandre Oliveira Barros Figueiredo1Hisao Takahashi2Cristiano Max Wrasse3Diego Barros4Nana Ama Browne Klutse5Solomon Otoo Lomotey6Toyese Tunde Ayorinde7Delano Gobbi8Anderson V. Bilibio9National Institute for Space Research (INPE), Division of Aeronomy Av. dos Astronautas, Sao Jose dos Campos CEP 12227-010, SP, BrazilNational Institute for Space Research (INPE), Division of Aeronomy Av. dos Astronautas, Sao Jose dos Campos CEP 12227-010, SP, BrazilNational Institute for Space Research (INPE), Division of Aeronomy Av. dos Astronautas, Sao Jose dos Campos CEP 12227-010, SP, BrazilNational Institute for Space Research (INPE), Division of Aeronomy Av. dos Astronautas, Sao Jose dos Campos CEP 12227-010, SP, BrazilNational Institute for Space Research (INPE), Division of Aeronomy Av. dos Astronautas, Sao Jose dos Campos CEP 12227-010, SP, BrazilClimate Change and Atmospheric Physics Center, African Institute for Mathematical Sciences (AIMS) Ghana, Accra P.O. Box LG DTD 20046, GhanaNational Institute for Space Research (INPE), Division of Aeronomy Av. dos Astronautas, Sao Jose dos Campos CEP 12227-010, SP, BrazilNational Institute for Space Research (INPE), Division of Aeronomy Av. dos Astronautas, Sao Jose dos Campos CEP 12227-010, SP, BrazilNational Institute for Space Research (INPE), Division of Aeronomy Av. dos Astronautas, Sao Jose dos Campos CEP 12227-010, SP, BrazilNational Institute for Space Research (INPE), Division of Aeronomy Av. dos Astronautas, Sao Jose dos Campos CEP 12227-010, SP, BrazilUsing data collected by the GNSS dual-frequency receivers network, de-trended TEC maps were generated to identify and characterize the medium-scale traveling ionospheric disturbances (MSTIDs) over the South American equatorial region (latitude: <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mn>0</mn><mo>∘</mo></msup></semantics></math></inline-formula> to <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mn>15</mn><mo>∘</mo></msup></semantics></math></inline-formula> S and longitude: <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mn>30</mn><mo>∘</mo></msup></semantics></math></inline-formula> to <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msup><mn>55</mn><mo>∘</mo></msup></semantics></math></inline-formula> W) during solar cycle 24 (from January 2014 to December 2019). A total of 712 MSTIDs were observed during quiet geomagnetic conditions. The Frequency of occurrence of MSTID is high during the solar maximum and low in the minimum phase. This might be due to the solar cycle dependence of gravity wave activity in the lower atmosphere and gravity wave propagation conditions in the thermosphere. The predominant daytime MSTIDs, representing 80% of the total observations, occurred in winter (June-August season in the southern hemisphere) with the secondary peak in the equinox; while the evening time MSTIDs, representing 18% of the entire events, occurred in summer (December to February season) and equinox (March to May and September to November), and the remaining 2% of the MSTIDs were observed during nighttime. The seasonal variation of the MSTID events was attributed to the source mechanisms generating them, the wind filtering and dissipation effects, and the local time dependency. The horizontal wavelengths of the MSTIDs were mostly concentrated between 500 and 800 km, with the mean value of 667 ± 131 km. The observed periods ranged from 30 to 45 min with the mean value of 36 ± 7 min. The observed horizontal phase speeds were distributed around 200 to 400 m/s, with the corresponding mean of 301 ± 75 m/s. The MSTIDs in the winter solstice and equinoctial months preferentially propagated northeastward and northwestward. Meanwhile, during the summer solstice, they propagated in all directions. The anisotropy of the propagation direction might be due to several reasons: the wind and dissipative filtering effects, ion drag effects, the primary source region, and the presence of the secondary or tertiary gravity waves in the thermosphere. Atmospheric gravity waves from strong convective sources might be the primary precursor for the observed equatorial MSTIDs. In all seasons, we noted that the MSTIDs propagating southeastward were probably excited by the likely gravity waves generated by the intertropical convergence zone (ITCZ).https://www.mdpi.com/2073-4433/12/11/1409medium-scale traveling ionospheric disturbancesequatorialdetrended TEC |
| spellingShingle | Patrick Essien Cosme Alexandre Oliveira Barros Figueiredo Hisao Takahashi Cristiano Max Wrasse Diego Barros Nana Ama Browne Klutse Solomon Otoo Lomotey Toyese Tunde Ayorinde Delano Gobbi Anderson V. Bilibio Long-Term Study on Medium-Scale Traveling Ionospheric Disturbances Observed over the South American Equatorial Region Atmosphere medium-scale traveling ionospheric disturbances equatorial detrended TEC |
| title | Long-Term Study on Medium-Scale Traveling Ionospheric Disturbances Observed over the South American Equatorial Region |
| title_full | Long-Term Study on Medium-Scale Traveling Ionospheric Disturbances Observed over the South American Equatorial Region |
| title_fullStr | Long-Term Study on Medium-Scale Traveling Ionospheric Disturbances Observed over the South American Equatorial Region |
| title_full_unstemmed | Long-Term Study on Medium-Scale Traveling Ionospheric Disturbances Observed over the South American Equatorial Region |
| title_short | Long-Term Study on Medium-Scale Traveling Ionospheric Disturbances Observed over the South American Equatorial Region |
| title_sort | long term study on medium scale traveling ionospheric disturbances observed over the south american equatorial region |
| topic | medium-scale traveling ionospheric disturbances equatorial detrended TEC |
| url | https://www.mdpi.com/2073-4433/12/11/1409 |
| work_keys_str_mv | AT patrickessien longtermstudyonmediumscaletravelingionosphericdisturbancesobservedoverthesouthamericanequatorialregion AT cosmealexandreoliveirabarrosfigueiredo longtermstudyonmediumscaletravelingionosphericdisturbancesobservedoverthesouthamericanequatorialregion AT hisaotakahashi longtermstudyonmediumscaletravelingionosphericdisturbancesobservedoverthesouthamericanequatorialregion AT cristianomaxwrasse longtermstudyonmediumscaletravelingionosphericdisturbancesobservedoverthesouthamericanequatorialregion AT diegobarros longtermstudyonmediumscaletravelingionosphericdisturbancesobservedoverthesouthamericanequatorialregion AT nanaamabrowneklutse longtermstudyonmediumscaletravelingionosphericdisturbancesobservedoverthesouthamericanequatorialregion AT solomonotoolomotey longtermstudyonmediumscaletravelingionosphericdisturbancesobservedoverthesouthamericanequatorialregion AT toyesetundeayorinde longtermstudyonmediumscaletravelingionosphericdisturbancesobservedoverthesouthamericanequatorialregion AT delanogobbi longtermstudyonmediumscaletravelingionosphericdisturbancesobservedoverthesouthamericanequatorialregion AT andersonvbilibio longtermstudyonmediumscaletravelingionosphericdisturbancesobservedoverthesouthamericanequatorialregion |