Equatorial plasma bubbles and L-band scintillations in Africa during solar minimum

V. V. Paznukhov, C. S. Carrano, P. H. Doherty, K. M. Groves, R. G. Caton, C. E. Valladares, G. K. Seemala, C. T. Bridgwood, J. Adeniyi, L. L N Amaeshi, B. Damtie, F. D'Ujanga Mutonyi, J. O H Ndeda, P. Baki, O. K. Obrou, B. Okere, G. M. Tsidu

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    Abstract

    We report on the longitudinal, local time and seasonal occurrence of equatorial plasma bubbles (EPBs) and L band (GPS) scintillations over equatorial Africa. The measurements were made in 2010, as a first step toward establishing the climatology of ionospheric irregularities over Africa. The scintillation intensity is obtained by measuring the standard deviation of normalized GPS signal power. The EPBs are detected using an automated technique, where spectral analysis is used to extract and identify EPB events from the GPS TEC measurements. Overall, the observed seasonal climatology of the EPBs as well as GPS scintillations in equatorial Africa is adequately explained by geometric arguments, i.e., by the alignment of the solar terminator and local geomagnetic field, or STBA hypothesis (Tsunoda, 1985, 2010a). While plasma bubbles and scintillations are primarily observed during equinoctial periods, there are longitudinal differences in their seasonal occurrence statistics. The Atlantic sector has the most intense, longest lasting, and highest scintillation occurrence rate in-season. There is also a pronounced increase in the EPB occurrence rate during the June solstice moving west to east. In Africa, the seasonal occurrence shifts towards boreal summer solstice, with fewer occurrences and shorter durations in equinox seasons. Our results also suggest that the occurrence of plasma bubbles and GPS scintillations over Africa are well correlated, with scintillation intensity depending on depletion depth. A question remains about the possible physical mechanisms responsible for the difference in the occurrence phenomenology of EPBs and GPS scintillations between different regions in equatorial Africa.

    Original languageEnglish
    Pages (from-to)675-682
    Number of pages8
    JournalAnnales Geophysicae
    Volume30
    Issue number4
    DOIs
    Publication statusPublished - 2012

    Fingerprint

    plasma bubbles
    ultrahigh frequencies
    scintillation
    bubble
    occurrences
    plasma
    GPS
    solstices
    climatology
    Africa
    geomagnetism
    irregularities
    geomagnetic field
    phenomenology
    spectral analysis
    ionospherics
    summer
    spectrum analysis
    standard deviation
    depletion

    All Science Journal Classification (ASJC) codes

    • Earth and Planetary Sciences (miscellaneous)
    • Atmospheric Science
    • Astronomy and Astrophysics
    • Space and Planetary Science
    • Geology

    Cite this

    Paznukhov, V. V., Carrano, C. S., Doherty, P. H., Groves, K. M., Caton, R. G., Valladares, C. E., ... Tsidu, G. M. (2012). Equatorial plasma bubbles and L-band scintillations in Africa during solar minimum. Annales Geophysicae, 30(4), 675-682. https://doi.org/10.5194/angeo-30-675-2012
    Paznukhov, V. V. ; Carrano, C. S. ; Doherty, P. H. ; Groves, K. M. ; Caton, R. G. ; Valladares, C. E. ; Seemala, G. K. ; Bridgwood, C. T. ; Adeniyi, J. ; Amaeshi, L. L N ; Damtie, B. ; D'Ujanga Mutonyi, F. ; Ndeda, J. O H ; Baki, P. ; Obrou, O. K. ; Okere, B. ; Tsidu, G. M. / Equatorial plasma bubbles and L-band scintillations in Africa during solar minimum. In: Annales Geophysicae. 2012 ; Vol. 30, No. 4. pp. 675-682.
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    abstract = "We report on the longitudinal, local time and seasonal occurrence of equatorial plasma bubbles (EPBs) and L band (GPS) scintillations over equatorial Africa. The measurements were made in 2010, as a first step toward establishing the climatology of ionospheric irregularities over Africa. The scintillation intensity is obtained by measuring the standard deviation of normalized GPS signal power. The EPBs are detected using an automated technique, where spectral analysis is used to extract and identify EPB events from the GPS TEC measurements. Overall, the observed seasonal climatology of the EPBs as well as GPS scintillations in equatorial Africa is adequately explained by geometric arguments, i.e., by the alignment of the solar terminator and local geomagnetic field, or STBA hypothesis (Tsunoda, 1985, 2010a). While plasma bubbles and scintillations are primarily observed during equinoctial periods, there are longitudinal differences in their seasonal occurrence statistics. The Atlantic sector has the most intense, longest lasting, and highest scintillation occurrence rate in-season. There is also a pronounced increase in the EPB occurrence rate during the June solstice moving west to east. In Africa, the seasonal occurrence shifts towards boreal summer solstice, with fewer occurrences and shorter durations in equinox seasons. Our results also suggest that the occurrence of plasma bubbles and GPS scintillations over Africa are well correlated, with scintillation intensity depending on depletion depth. A question remains about the possible physical mechanisms responsible for the difference in the occurrence phenomenology of EPBs and GPS scintillations between different regions in equatorial Africa.",
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    Paznukhov, VV, Carrano, CS, Doherty, PH, Groves, KM, Caton, RG, Valladares, CE, Seemala, GK, Bridgwood, CT, Adeniyi, J, Amaeshi, LLN, Damtie, B, D'Ujanga Mutonyi, F, Ndeda, JOH, Baki, P, Obrou, OK, Okere, B & Tsidu, GM 2012, 'Equatorial plasma bubbles and L-band scintillations in Africa during solar minimum', Annales Geophysicae, vol. 30, no. 4, pp. 675-682. https://doi.org/10.5194/angeo-30-675-2012

    Equatorial plasma bubbles and L-band scintillations in Africa during solar minimum. / Paznukhov, V. V.; Carrano, C. S.; Doherty, P. H.; Groves, K. M.; Caton, R. G.; Valladares, C. E.; Seemala, G. K.; Bridgwood, C. T.; Adeniyi, J.; Amaeshi, L. L N; Damtie, B.; D'Ujanga Mutonyi, F.; Ndeda, J. O H; Baki, P.; Obrou, O. K.; Okere, B.; Tsidu, G. M.

    In: Annales Geophysicae, Vol. 30, No. 4, 2012, p. 675-682.

    Research output: Contribution to journalArticle

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    T1 - Equatorial plasma bubbles and L-band scintillations in Africa during solar minimum

    AU - Paznukhov, V. V.

    AU - Carrano, C. S.

    AU - Doherty, P. H.

    AU - Groves, K. M.

    AU - Caton, R. G.

    AU - Valladares, C. E.

    AU - Seemala, G. K.

    AU - Bridgwood, C. T.

    AU - Adeniyi, J.

    AU - Amaeshi, L. L N

    AU - Damtie, B.

    AU - D'Ujanga Mutonyi, F.

    AU - Ndeda, J. O H

    AU - Baki, P.

    AU - Obrou, O. K.

    AU - Okere, B.

    AU - Tsidu, G. M.

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    N2 - We report on the longitudinal, local time and seasonal occurrence of equatorial plasma bubbles (EPBs) and L band (GPS) scintillations over equatorial Africa. The measurements were made in 2010, as a first step toward establishing the climatology of ionospheric irregularities over Africa. The scintillation intensity is obtained by measuring the standard deviation of normalized GPS signal power. The EPBs are detected using an automated technique, where spectral analysis is used to extract and identify EPB events from the GPS TEC measurements. Overall, the observed seasonal climatology of the EPBs as well as GPS scintillations in equatorial Africa is adequately explained by geometric arguments, i.e., by the alignment of the solar terminator and local geomagnetic field, or STBA hypothesis (Tsunoda, 1985, 2010a). While plasma bubbles and scintillations are primarily observed during equinoctial periods, there are longitudinal differences in their seasonal occurrence statistics. The Atlantic sector has the most intense, longest lasting, and highest scintillation occurrence rate in-season. There is also a pronounced increase in the EPB occurrence rate during the June solstice moving west to east. In Africa, the seasonal occurrence shifts towards boreal summer solstice, with fewer occurrences and shorter durations in equinox seasons. Our results also suggest that the occurrence of plasma bubbles and GPS scintillations over Africa are well correlated, with scintillation intensity depending on depletion depth. A question remains about the possible physical mechanisms responsible for the difference in the occurrence phenomenology of EPBs and GPS scintillations between different regions in equatorial Africa.

    AB - We report on the longitudinal, local time and seasonal occurrence of equatorial plasma bubbles (EPBs) and L band (GPS) scintillations over equatorial Africa. The measurements were made in 2010, as a first step toward establishing the climatology of ionospheric irregularities over Africa. The scintillation intensity is obtained by measuring the standard deviation of normalized GPS signal power. The EPBs are detected using an automated technique, where spectral analysis is used to extract and identify EPB events from the GPS TEC measurements. Overall, the observed seasonal climatology of the EPBs as well as GPS scintillations in equatorial Africa is adequately explained by geometric arguments, i.e., by the alignment of the solar terminator and local geomagnetic field, or STBA hypothesis (Tsunoda, 1985, 2010a). While plasma bubbles and scintillations are primarily observed during equinoctial periods, there are longitudinal differences in their seasonal occurrence statistics. The Atlantic sector has the most intense, longest lasting, and highest scintillation occurrence rate in-season. There is also a pronounced increase in the EPB occurrence rate during the June solstice moving west to east. In Africa, the seasonal occurrence shifts towards boreal summer solstice, with fewer occurrences and shorter durations in equinox seasons. Our results also suggest that the occurrence of plasma bubbles and GPS scintillations over Africa are well correlated, with scintillation intensity depending on depletion depth. A question remains about the possible physical mechanisms responsible for the difference in the occurrence phenomenology of EPBs and GPS scintillations between different regions in equatorial Africa.

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    Paznukhov VV, Carrano CS, Doherty PH, Groves KM, Caton RG, Valladares CE et al. Equatorial plasma bubbles and L-band scintillations in Africa during solar minimum. Annales Geophysicae. 2012;30(4):675-682. https://doi.org/10.5194/angeo-30-675-2012