First observations of Southern Hemisphere polar mesosphere winter echoes including conjugate occurrences at 69 degree S latitude

We present the first account of polar mesosphere winter echoes (PMWE) observed from the Southern Hemisphere (SH), using measurements from Davis, Antarctica (68.6 degree S; 78.0 degree E). PMWE were observed by mesosphere-stratosphere-troposphere (MST) radar during solar proton events (SPEs) and auro...

Full description

Saved in:
Bibliographic Details
Published in:Geophysical research letters 2011-02, Vol.38 (3), p.np-np
Main Authors: Morris, Ray J, Klekociuk, Andrew R, Holdsworth, David A
Format: Article
Language:English
Subjects:
Echoes
Fluid dynamics
Mesosphere
Polar mesosphere
Radar
Southern Hemisphere
Turbulence
Winter
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:We present the first account of polar mesosphere winter echoes (PMWE) observed from the Southern Hemisphere (SH), using measurements from Davis, Antarctica (68.6 degree S; 78.0 degree E). PMWE were observed by mesosphere-stratosphere-troposphere (MST) radar during solar proton events (SPEs) and auroral substorms. We supplement the MST radar measurements with profiles of temperature and turbulent velocity from co-located Rayleigh lidar and medium frequency (MF) radar, respectively, as well as temperature data from the Microwave Limb Sounder (MLS) onboard the Aura satellite. We establish that SH PMWE exhibit similar characteristics to their well-studied northern hemisphere counterpart. Significantly our observations reveal that these radar echoes in the lower mesosphere (50-80 km) can occur year-round, and on occasions simultaneously in both hemispheres. We report the seasonal occurrence distribution of SH PMWE is linked to the seasonal distribution of atmospheric turbulence in the lower mesosphere. We hypothesise that given sufficient turbulent velocities in the neutral atmosphere and co-located gradients in electron density, PMWE can occur throughout the year. However they are more likely in winter when turbulent velocities in the lower mesosphere maximise.
ISSN:0094-8276
1944-8007
DOI:10.1029/2010GL046298