Lidar observations of Ca and K metallic layers from Arecibo and comparison with micrometeor sporadic activity

S. Raizada, C. A. Tepley, D. Janches, J. S. Friedman, Q. Zhou, John David Mathews

    Research output: Contribution to journalArticle

    34 Citations (Scopus)

    Abstract

    We report on the first simultaneous observations of Ca and K metallic layers using the low-latitude lidar systems located at the Arecibo Observatory in Puerto Rico (18.35°N, 66.75°W). We often observe sudden increases in both Ca and K densities during early morning hours on nights where meteor showers take place. During these periods, the Ca/K abundance ratio varied between 2 and 3. On occasion, differences were observed in Ca and K layers, which relate to differences in the chemistry of the two metals. It is known that metallic layers display distinct seasonal variations, but chemistry alone cannot explain the measured differences. Thus, we examined whether or not the seasonal distribution of micrometeoroids, derived from meteor observations using the Arecibo 430 MHz radar, can account for the dissimilar metallic observations. We found that the deposition flux of micrometeoroids, with particle sizes ranging between 0.5 and 100 μm, increased by a factor of two during the summer as compared with the winter, suggesting a seasonal variation of their sporadic activity. In addition, our data support the idea that differential ablation leads to a depletion of Ca atoms in the mesosphere.

    Original languageEnglish (US)
    Pages (from-to)595-606
    Number of pages12
    JournalJournal of Atmospheric and Solar-Terrestrial Physics
    Volume66
    Issue number6-9
    DOIs
    StatePublished - Apr 1 2004

    Fingerprint

    micrometeoroids
    optical radar
    lidar
    meteoroids
    meteor
    annual variations
    seasonal variation
    Puerto Rico
    chemistry
    morning
    mesosphere
    showers
    tropical regions
    ablation
    night
    winter
    summer
    radar
    observatories
    depletion

    All Science Journal Classification (ASJC) codes

    • Geophysics
    • Atmospheric Science
    • Space and Planetary Science

    Cite this

    Raizada, S. ; Tepley, C. A. ; Janches, D. ; Friedman, J. S. ; Zhou, Q. ; Mathews, John David. / Lidar observations of Ca and K metallic layers from Arecibo and comparison with micrometeor sporadic activity. In: Journal of Atmospheric and Solar-Terrestrial Physics. 2004 ; Vol. 66, No. 6-9. pp. 595-606.
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    Lidar observations of Ca and K metallic layers from Arecibo and comparison with micrometeor sporadic activity. / Raizada, S.; Tepley, C. A.; Janches, D.; Friedman, J. S.; Zhou, Q.; Mathews, John David.

    In: Journal of Atmospheric and Solar-Terrestrial Physics, Vol. 66, No. 6-9, 01.04.2004, p. 595-606.

    Research output: Contribution to journalArticle

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    AU - Raizada, S.

    AU - Tepley, C. A.

    AU - Janches, D.

    AU - Friedman, J. S.

    AU - Zhou, Q.

    AU - Mathews, John David

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    N2 - We report on the first simultaneous observations of Ca and K metallic layers using the low-latitude lidar systems located at the Arecibo Observatory in Puerto Rico (18.35°N, 66.75°W). We often observe sudden increases in both Ca and K densities during early morning hours on nights where meteor showers take place. During these periods, the Ca/K abundance ratio varied between 2 and 3. On occasion, differences were observed in Ca and K layers, which relate to differences in the chemistry of the two metals. It is known that metallic layers display distinct seasonal variations, but chemistry alone cannot explain the measured differences. Thus, we examined whether or not the seasonal distribution of micrometeoroids, derived from meteor observations using the Arecibo 430 MHz radar, can account for the dissimilar metallic observations. We found that the deposition flux of micrometeoroids, with particle sizes ranging between 0.5 and 100 μm, increased by a factor of two during the summer as compared with the winter, suggesting a seasonal variation of their sporadic activity. In addition, our data support the idea that differential ablation leads to a depletion of Ca atoms in the mesosphere.

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