Polar mesosphere summer echoes: a comparison of simultaneous observations at three wavelengths
On 5 July 2005, simultaneous observations of Polar Mesosphere Summer Echoes (PMSE) were made using the EISCAT VHF (224 MHz) and UHF (933 MHz) radars located near Tromsø, Norway and the ALWIN VHF radar (53.5 MHz) situated on Andøya, 120 km SW of the EISCAT site. During the short interval from 12:20 U...
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ftdoajarticles:oai:doaj.org/article:193b2fbc5b584ac887bb5f237b9b3df8 2023-05-15T13:25:44+02:00 Polar mesosphere summer echoes: a comparison of simultaneous observations at three wavelengths E. Belova P. Dalin S. Kirkwood 2007-01-01T00:00:00Z https://doi.org/10.5194/angeo-25-2487-2007 https://doaj.org/article/193b2fbc5b584ac887bb5f237b9b3df8 EN eng Copernicus Publications https://www.ann-geophys.net/25/2487/2007/angeo-25-2487-2007.pdf https://doaj.org/toc/0992-7689 https://doaj.org/toc/1432-0576 doi:10.5194/angeo-25-2487-2007 0992-7689 1432-0576 https://doaj.org/article/193b2fbc5b584ac887bb5f237b9b3df8 Annales Geophysicae, Vol 25, Pp 2487-2496 (2007) Science Q Physics QC1-999 Geophysics. Cosmic physics QC801-809 article 2007 ftdoajarticles https://doi.org/10.5194/angeo-25-2487-2007 2022-12-31T13:47:32Z On 5 July 2005, simultaneous observations of Polar Mesosphere Summer Echoes (PMSE) were made using the EISCAT VHF (224 MHz) and UHF (933 MHz) radars located near Tromsø, Norway and the ALWIN VHF radar (53.5 MHz) situated on Andøya, 120 km SW of the EISCAT site. During the short interval from 12:20 UT until 12:26 UT strong echoes at about 84 km altitude were detected with all three radars. The radar volume reflectivities were found to be 4×10 −13 m −1 , 1.5×10 −14 m −1 and 1.5×10 −18 m −1 for the ALWIN, EISCAT-VHF and UHF radars, respectively. We have calculated the reflectivity ratios for each pair of radars and have compared them to ratios obtained from the turbulence-theory model proposed by Hill (1978a). We have tested different values of the turbulent energy dissipation rate ε and Schmidt number S c , which are free parameters in the model, to try to fit theoretical reflectivity ratios to the experimental ones. No single combination of the parameters ε and S c could be found to give a good fit. Spectral widths for the EISCAT radars were estimated from the spectra computed from the autocorrelation functions obtained in the experiment. After correction for beam-width broadening, the spectral widths are about 4 m/s for the EISCAT-VHF and 1.5–2 m/s for the UHF radar. However, according to the turbulence theory, the spectral widths in m/s should be the same for both radars. We also tested an incoherent scatter (IS) model developed by Cho et al. (1998), which takes into account the presence of charged aerosols/dust at the summer mesopause. It required very different sizes of particles for the EISCAT-VHF and UHF cases, to be able to fit the experimental spectra with model spectra. This implies that the IS model cannot explain PMSE spectra, at least not for monodisperse distributions of particles. Article in Journal/Newspaper Andøya EISCAT Tromsø Directory of Open Access Journals: DOAJ Articles Norway Tromsø Andøya ENVELOPE(13.982,13.982,68.185,68.185) Annales Geophysicae 25 12 2487 2496 |
institution |
Open Polar |
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Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Science Q Physics QC1-999 Geophysics. Cosmic physics QC801-809 |
spellingShingle |
Science Q Physics QC1-999 Geophysics. Cosmic physics QC801-809 E. Belova P. Dalin S. Kirkwood Polar mesosphere summer echoes: a comparison of simultaneous observations at three wavelengths |
topic_facet |
Science Q Physics QC1-999 Geophysics. Cosmic physics QC801-809 |
description |
On 5 July 2005, simultaneous observations of Polar Mesosphere Summer Echoes (PMSE) were made using the EISCAT VHF (224 MHz) and UHF (933 MHz) radars located near Tromsø, Norway and the ALWIN VHF radar (53.5 MHz) situated on Andøya, 120 km SW of the EISCAT site. During the short interval from 12:20 UT until 12:26 UT strong echoes at about 84 km altitude were detected with all three radars. The radar volume reflectivities were found to be 4×10 −13 m −1 , 1.5×10 −14 m −1 and 1.5×10 −18 m −1 for the ALWIN, EISCAT-VHF and UHF radars, respectively. We have calculated the reflectivity ratios for each pair of radars and have compared them to ratios obtained from the turbulence-theory model proposed by Hill (1978a). We have tested different values of the turbulent energy dissipation rate ε and Schmidt number S c , which are free parameters in the model, to try to fit theoretical reflectivity ratios to the experimental ones. No single combination of the parameters ε and S c could be found to give a good fit. Spectral widths for the EISCAT radars were estimated from the spectra computed from the autocorrelation functions obtained in the experiment. After correction for beam-width broadening, the spectral widths are about 4 m/s for the EISCAT-VHF and 1.5–2 m/s for the UHF radar. However, according to the turbulence theory, the spectral widths in m/s should be the same for both radars. We also tested an incoherent scatter (IS) model developed by Cho et al. (1998), which takes into account the presence of charged aerosols/dust at the summer mesopause. It required very different sizes of particles for the EISCAT-VHF and UHF cases, to be able to fit the experimental spectra with model spectra. This implies that the IS model cannot explain PMSE spectra, at least not for monodisperse distributions of particles. |
format |
Article in Journal/Newspaper |
author |
E. Belova P. Dalin S. Kirkwood |
author_facet |
E. Belova P. Dalin S. Kirkwood |
author_sort |
E. Belova |
title |
Polar mesosphere summer echoes: a comparison of simultaneous observations at three wavelengths |
title_short |
Polar mesosphere summer echoes: a comparison of simultaneous observations at three wavelengths |
title_full |
Polar mesosphere summer echoes: a comparison of simultaneous observations at three wavelengths |
title_fullStr |
Polar mesosphere summer echoes: a comparison of simultaneous observations at three wavelengths |
title_full_unstemmed |
Polar mesosphere summer echoes: a comparison of simultaneous observations at three wavelengths |
title_sort |
polar mesosphere summer echoes: a comparison of simultaneous observations at three wavelengths |
publisher |
Copernicus Publications |
publishDate |
2007 |
url |
https://doi.org/10.5194/angeo-25-2487-2007 https://doaj.org/article/193b2fbc5b584ac887bb5f237b9b3df8 |
long_lat |
ENVELOPE(13.982,13.982,68.185,68.185) |
geographic |
Norway Tromsø Andøya |
geographic_facet |
Norway Tromsø Andøya |
genre |
Andøya EISCAT Tromsø |
genre_facet |
Andøya EISCAT Tromsø |
op_source |
Annales Geophysicae, Vol 25, Pp 2487-2496 (2007) |
op_relation |
https://www.ann-geophys.net/25/2487/2007/angeo-25-2487-2007.pdf https://doaj.org/toc/0992-7689 https://doaj.org/toc/1432-0576 doi:10.5194/angeo-25-2487-2007 0992-7689 1432-0576 https://doaj.org/article/193b2fbc5b584ac887bb5f237b9b3df8 |
op_doi |
https://doi.org/10.5194/angeo-25-2487-2007 |
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Annales Geophysicae |
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25 |
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12 |
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2487 |
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2496 |
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