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www.atmos-chem-phys-discuss.net/7/7035/2007/
doi:10.5194/acpd-7-7035-2007
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Mesospheric turbulence during PMWE-conducive conditions
1Tromsø Geophysical Observatory, University of Tromsø, Norway
2University of Saskatchewan, Saskatoon, Canada
3Nagoya University, Nagoya, Japan
Abstract. Strong radar returns at VHF known as Polar Mesospheric Winter Echoes (PMWE) seem to occur during periods of intense ionisation of the mesosphere. Apart from a mechanism to produce such ionisation, viz. solar proton precipitation, other prerequisites have been proposed, such as neutral air turbulence. Here, we employ a medium frequency radar to examine whether the atmospheric state is conducive to the appearance of PMWE; echo power signatures (isolated lower mesospheric echoes – "ILME") are indicators of the necessary ionisation at sufficient depth in the middle atmosphere, and also echo fading times give information on turbulence. We fail to find evidence for causal relationship between ILME and turbulence but suggest that on occasion turbulence may be enhanced related to proton precipitation. The results presented provide a basis for investigating whether turbulence is a prerequisite for PMWE.
Discussion Paper (PDF, 643 KB) Interactive Discussion (Closed, 3 Comments) Publication in ACP not foreseen
Citation: Hall, C. M., Manson, A. H., Meek, C. E., and Nozawa, S.: Mesospheric turbulence during PMWE-conducive conditions, Atmos. Chem. Phys. Discuss., 7, 7035-7049, doi:10.5194/acpd-7-7035-2007, 2007. Bibtex EndNote Reference Manager XML
