Polar mesosphere summer echoes: a comparison of simultaneous observations at three wavelengths
International audience 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 shor...
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ftccsdartic:oai:HAL:hal-00318415v1 2023-11-12T04:01:06+01:00 Polar mesosphere summer echoes: a comparison of simultaneous observations at three wavelengths Belova, E. Dalin, P. Kirkwood, S. Swedish Institute of Space Physics Kiruna (IRF) 2008-01-02 https://hal.science/hal-00318415 https://hal.science/hal-00318415/document https://hal.science/hal-00318415/file/angeo-25-2487-2007.pdf en eng HAL CCSD European Geosciences Union hal-00318415 https://hal.science/hal-00318415 https://hal.science/hal-00318415/document https://hal.science/hal-00318415/file/angeo-25-2487-2007.pdf info:eu-repo/semantics/OpenAccess ISSN: 0992-7689 EISSN: 1432-0576 Annales Geophysicae https://hal.science/hal-00318415 Annales Geophysicae, 2008, 25 (12), pp.2487-2496 [SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere [SDU.STU]Sciences of the Universe [physics]/Earth Sciences info:eu-repo/semantics/article Journal articles 2008 ftccsdartic 2023-10-21T23:06:31Z International audience 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 ? 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 ? 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 Archive ouverte HAL (Hyper Article en Ligne, CCSD - Centre pour la Communication Scientifique Directe) Norway Tromsø Andøya ENVELOPE(13.982,13.982,68.185,68.185) |
institution |
Open Polar |
collection |
Archive ouverte HAL (Hyper Article en Ligne, CCSD - Centre pour la Communication Scientifique Directe) |
op_collection_id |
ftccsdartic |
language |
English |
topic |
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere [SDU.STU]Sciences of the Universe [physics]/Earth Sciences |
spellingShingle |
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere [SDU.STU]Sciences of the Universe [physics]/Earth Sciences Belova, E. Dalin, P. Kirkwood, S. Polar mesosphere summer echoes: a comparison of simultaneous observations at three wavelengths |
topic_facet |
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere [SDU.STU]Sciences of the Universe [physics]/Earth Sciences |
description |
International audience 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 ? 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 ? 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. |
author2 |
Swedish Institute of Space Physics Kiruna (IRF) |
format |
Article in Journal/Newspaper |
author |
Belova, E. Dalin, P. Kirkwood, S. |
author_facet |
Belova, E. Dalin, P. Kirkwood, S. |
author_sort |
Belova, E. |
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 |
HAL CCSD |
publishDate |
2008 |
url |
https://hal.science/hal-00318415 https://hal.science/hal-00318415/document https://hal.science/hal-00318415/file/angeo-25-2487-2007.pdf |
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 |
ISSN: 0992-7689 EISSN: 1432-0576 Annales Geophysicae https://hal.science/hal-00318415 Annales Geophysicae, 2008, 25 (12), pp.2487-2496 |
op_relation |
hal-00318415 https://hal.science/hal-00318415 https://hal.science/hal-00318415/document https://hal.science/hal-00318415/file/angeo-25-2487-2007.pdf |
op_rights |
info:eu-repo/semantics/OpenAccess |
_version_ |
1782329845187870720 |