Journal cover Journal topic
Annales Geophysicae An interactive open-access journal of the European Geosciences Union
Journal topic

Journal metrics

Journal metrics

  • IF value: 1.621 IF 1.621
  • IF 5-year value: 1.614 IF 5-year
    1.614
  • CiteScore value: 1.61 CiteScore
    1.61
  • SNIP value: 0.900 SNIP 0.900
  • IPP value: 1.58 IPP 1.58
  • SJR value: 0.910 SJR 0.910
  • Scimago H <br class='hide-on-tablet hide-on-mobile'>index value: 80 Scimago H
    index 80
  • h5-index value: 24 h5-index 24
Volume 27, issue 7
Ann. Geophys., 27, 2937-2945, 2009
https://doi.org/10.5194/angeo-27-2937-2009
© Author(s) 2009. This work is distributed under
the Creative Commons Attribution 3.0 License.

Special issue: 12th International Symposium on Equatorial Aeronomy...

Ann. Geophys., 27, 2937-2945, 2009
https://doi.org/10.5194/angeo-27-2937-2009
© Author(s) 2009. This work is distributed under
the Creative Commons Attribution 3.0 License.

  24 Jul 2009

24 Jul 2009

Overturning instability in the mesosphere and lower thermosphere: analysis of instability conditions in lidar data

L. Hurd1, M. F. Larsen1, and A. Z. Liu2 L. Hurd et al.
  • 1Department of Physics and Astronomy, Clemson University, Clemson, SC, USA
  • 2Department of Electrical and Computer Engineering, University of Illinois, Urbana, IL, USA

Abstract. Resonant sodium lidar measurements from the transition region between the mesosphere and lower thermosphere have revealed frequently-occurring overturning events characterized by vertical scales of ~3–6 km and timescales of several hours. Larsen et al. (2004) proposed that a convective roll instability, similar to that found in the planetary boundary layer, is the likely mechanism responsible for the events. This type of instability requires an inflection point in the background winds near the center of the vortex roll with a low static stability region capped by an inversion. The earlier paper argued that the conditions required to support the instability are common in the altitude range where the features are found. In this paper, we use data from the University of Illinois sodium lidar that was located at the Starfire Optical Range near Albuquerque, New Mexico, and from the Maui/MALT Lidar Facility in Hawaii and present several cases that are used to examine the behavior of the inflection point in detail as a function of time during the evolution of the overturning event. In addition, we examine the background static stability conditions using the temperature data from the lidar.

Publications Copernicus
Special issue
Download
Citation
Share