TY - JOUR
T1 - VIPIR and 50 MHz Radar Studies of Gravity Wave Signatures in 150-km Echoes Observed at Jicamarca
AU - Reyes, Pablo M.
AU - Kudeki, Erhan
AU - Lehmacher, Gerald A.
AU - Chau, Jorge L.
AU - Milla, Marco A.
N1 - Funding Information:
E. Kudeki and P. Reyes were supported by NSF Grant AGS‐1143523. G. Lehmacher was supported by NSF Grant AGS‐1143514. Jicamarca is a facility of the Instituto Geofísico del Perú operated with support from the NSF Grant AGS‐1433968 through Cornell University. We thank the Jicamarca staff for supporting the MST‐ISR and MST‐EEJ‐ISR experiments. The participation of J. L. C. in this work is part of the project supported by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) under SPP 1788 (DynamicEarth)‐CH 1482/1‐2 (DYNAMITE2). We thank the International Space Science Institute for facilitating discussions related to this paper as part of the International Team “An Exploration of the Valley Region in the Low Latitude Ionosphere: Response to Forcing from Below and Above and Relevance to Space Weather”.
Funding Information:
E. Kudeki and P. Reyes were supported by NSF Grant AGS-1143523. G. Lehmacher was supported by NSF Grant AGS-1143514. Jicamarca is a facility of the Instituto Geof?sico del Per? operated with support from the NSF Grant AGS-1433968 through Cornell University. We thank the Jicamarca staff for supporting the MST-ISR and MST-EEJ-ISR experiments. The participation of J. L. C. in this work is part of the project supported by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) under SPP 1788 (DynamicEarth)-CH 1482/1-2 (DYNAMITE2). We thank the International Space Science Institute for facilitating discussions related to this paper as part of the International Team ?An Exploration of the Valley Region in the Low Latitude Ionosphere: Response to Forcing from Below and Above and Relevance to Space Weather?.
Publisher Copyright:
©2020. American Geophysical Union. All Rights Reserved.
PY - 2020/8/1
Y1 - 2020/8/1
N2 - Range-time-intensity (RTI) plots of 50 MHz radar backscatter detected at Jicamarca from the 150-km region of the equatorial ionosphere exhibit necklace-shaped multilayered structures first reported by Kudeki and Fawcett (1993, https://doi.org/10.1029/93GL01256). The backscatter layers also exhibit quasi-periodic intensity fluctuations with periods of about 5–15 min and are separated from adjacent layers by thin and undulating regions of no detectible power returns. A study of the fluctuating backscatter layers and undulating gap regions will be presented using VIPIR ionosonde data taken at the Jicamarca Radio Observatory simultaneously with high-resolution 50-MHz radar backscatter data. VIPIR virtual reflection height variations in time are noted to match the RTI gap-region undulations very closely at selected VIPIR frequencies (or, equivalently, electron densities at reflection heights). This matching enables assigning “true heights” to VIPIR virtual height contour maps, and a joint study of the contour maps with the 50-MHz radar RTI maps strongly suggests that correlated fluctuations and undulations observed in VIPIR and 50-MHz radar data are indicative of gravity wave-induced variations in the 150-km region ionosphere. Accordingly, a complete explanation of the 150-km echo phenomenon will need to include gravity wave coupling and forcing effects in the enhancement and suppression processes that can account for the observed fluctuations and gap-region features of necklace-shaped 150-km echo maps.
AB - Range-time-intensity (RTI) plots of 50 MHz radar backscatter detected at Jicamarca from the 150-km region of the equatorial ionosphere exhibit necklace-shaped multilayered structures first reported by Kudeki and Fawcett (1993, https://doi.org/10.1029/93GL01256). The backscatter layers also exhibit quasi-periodic intensity fluctuations with periods of about 5–15 min and are separated from adjacent layers by thin and undulating regions of no detectible power returns. A study of the fluctuating backscatter layers and undulating gap regions will be presented using VIPIR ionosonde data taken at the Jicamarca Radio Observatory simultaneously with high-resolution 50-MHz radar backscatter data. VIPIR virtual reflection height variations in time are noted to match the RTI gap-region undulations very closely at selected VIPIR frequencies (or, equivalently, electron densities at reflection heights). This matching enables assigning “true heights” to VIPIR virtual height contour maps, and a joint study of the contour maps with the 50-MHz radar RTI maps strongly suggests that correlated fluctuations and undulations observed in VIPIR and 50-MHz radar data are indicative of gravity wave-induced variations in the 150-km region ionosphere. Accordingly, a complete explanation of the 150-km echo phenomenon will need to include gravity wave coupling and forcing effects in the enhancement and suppression processes that can account for the observed fluctuations and gap-region features of necklace-shaped 150-km echo maps.
KW - 150-km echoes
KW - equatorial ionosphere
KW - gravity waves
KW - ionospheric sounding
KW - radar scattering
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U2 - 10.1029/2019JA027535
DO - 10.1029/2019JA027535
M3 - Article
AN - SCOPUS:85089902028
SN - 2169-9380
VL - 125
JO - Journal of Geophysical Research: Space Physics
JF - Journal of Geophysical Research: Space Physics
IS - 8
M1 - e2019JA027535
ER -