High-resolution observations of mesospheric layers with the Jicamarca VHF radar

G. A. Lehmacher, L. Guo, E. Kudeki, P. M. Reyes, A. Akgiray, J. L. Chau

Research output: Contribution to journalArticle

Abstract

We report new results from the 50-MHz Jicamarca radar in Peru (12°S, 77°W), which is able to observe backscatter from the daytime mesosphere on any given day. Since 2005, the radar has been operated in a high-power MST-ISR mode for 3-day runs four times per year to study the seasonal variation of mesospheric echoes. Doppler spectra are obtained with 1 min and 150-m nominal resolution yielding power, horizontal and vertical winds, and spectral width. The rich echo structures contain braids and billows suggestive of Kelvin-Helmholtz instability (KHI). We present three cases; (1) a short sequence of billows growing in height and becoming unstable; (2) a long train of billows showing high levels of turbulence at two different locations; and (3) a series of billows passing only slowly through the field of view. In all cases, the layers were associated with strong wind shears, mature billows were 1-1.5 km tall, and separation of KH phase fronts was 8-10 km. We compare our observations with OH imager observation and numerical simulations.

Original languageEnglish (US)
Pages (from-to)734-743
Number of pages10
JournalAdvances in Space Research
Volume40
Issue number6
DOIs
StatePublished - Jan 1 2007

Keywords

  • Equatorial mesosphere
  • Kelvin-Helmholtz instability
  • Turbulence
  • VHF echoes
  • VHF radar

ASJC Scopus subject areas

  • Aerospace Engineering
  • Astronomy and Astrophysics
  • Geophysics
  • Atmospheric Science
  • Space and Planetary Science
  • Earth and Planetary Sciences(all)

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