Quasi-periodic backscatters from the E region at Gadanki: Evidence for Kelvin-Helmholtz billows in the lower thermosphere?

Details Quasi-periodic backscatters from the E region at Gadanki: Evidence for Kelvin-Helmholtz billows in the lower thermosphere? Quasi-periodic backscatters from the E region at Gadanki: Evidence for Kelvin-Helmholtz billows in the lower thermosphere?

Aug 2005

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2005jgra..11008303c&link_type=abstract

Journal of Geophysical Research, Volume 110, Issue A8, CiteID A08303

Physics

8

Ionosphere: Ionospheric Irregularities, Ionosphere: Midlatitude Ionosphere, Ionosphere: Plasma Waves And Instabilities (2772), Radio Science: Waves In Plasma (7867), Radio Science: Radar Atmospheric Physics (1220)

Scientific paper

Analyzing the field-aligned coherent radar backscatter observed over Gadanki, India (13.5°N, 79.2°E), with a narrow beam pointing almost vertically, we present convincing experimental evidence for the presence of low-latitudes tilted sporadic ionization layers close to 10 km in vertical extent that move horizontally through the field of view of the radar. Using the data from high temporal (~3 s) resolution experiments, we also show that the line-of-sight Doppler velocities associated with at least some of the quasi-periodic striations have very clear vortex-like structures cutting across a vertical plane inside regions of strong horizontal wind shears. The power as well as the Doppler width peak together, and they often reach their peak values near the center of a vortex, where the magnitude of the Doppler velocity is minimum. The Doppler properties and spatial distribution of the 3 m echoes are explained in terms of a local electrodynamical process that makes ions and electrons move with the vertical neutral wind. Both the wind field and the tilt of the layers are in turn consistent with the presence of Kelvin-Helmholtz billows. We postulate that the billows themselves are triggered by a shear instability in the large ambient zonal wind; strong zonal wind shears clearly have to be present when sporadic E layers are observed. In our case, the breaking of an originally uniform and horizontal sporadic E layer into tilted pieces aligned more or less parallel to one another, and their motion through the radar field of view in the presence of a mean zonal wind, give the echoes their quasi-periodic appearance.

Affiliated with

Also associated with

No associations

Rating

Quasi-periodic backscatters from the E region at Gadanki: Evidence for Kelvin-Helmholtz billows in the lower thermosphere? does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Quasi-periodic backscatters from the E region at Gadanki: Evidence for Kelvin-Helmholtz billows in the lower thermosphere?, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Quasi-periodic backscatters from the E region at Gadanki: Evidence for Kelvin-Helmholtz billows in the lower thermosphere? will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-855923