The thermal and dynamical state of the atmosphere during polar mesosphere winter echoes
International audience In January 2005, a total of 18 rockets were launched from the Andøya Rocket Range in Northern Norway (69° N) into strong VHF radar echoes called 'Polar Mesosphere Winter Echoes' (PMWE). The echoes were observed in the lower and middle mesosphere during large solar pr...
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ftinsu:oai:HAL:hal-00301733v1 2023-11-12T04:01:06+01:00 The thermal and dynamical state of the atmosphere during polar mesosphere winter echoes Lübken, F.-J. Strelnikov, B. Rapp, M. Singer, W. Latteck, R. Brattli, A. Hoppe, U.-P. Friedrich, M. Leibniz-Institute of Atmospheric Physics (AIP) Norwegian Defence Research Establishment (FFI) Institute of Communications Networks and Satellite Communications 2005-08-29 https://hal.science/hal-00301733 https://hal.science/hal-00301733/document https://hal.science/hal-00301733/file/acpd-5-7613-2005.pdf en eng HAL CCSD European Geosciences Union hal-00301733 https://hal.science/hal-00301733 https://hal.science/hal-00301733/document https://hal.science/hal-00301733/file/acpd-5-7613-2005.pdf info:eu-repo/semantics/OpenAccess ISSN: 1680-7367 EISSN: 1680-7375 Atmospheric Chemistry and Physics Discussions https://hal.science/hal-00301733 Atmospheric Chemistry and Physics Discussions, 2005, 5 (4), pp.7613-7645 [SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere info:eu-repo/semantics/article Journal articles 2005 ftinsu 2023-10-25T16:26:53Z International audience In January 2005, a total of 18 rockets were launched from the Andøya Rocket Range in Northern Norway (69° N) into strong VHF radar echoes called 'Polar Mesosphere Winter Echoes' (PMWE). The echoes were observed in the lower and middle mesosphere during large solar proton fluxes. In general, PMWE are much more seldom compared to their summer counterparts PMSE (typical occurrence rates at 69° N are 1?3% vs. 80%, respectively). Our in-situ measurements by falling sphere, chaff, and instrumented payloads provide detailed information about the thermal and dynamical state of the atmosphere and therefore allow an unprecedented study of the background atmosphere during PMWE. There are a number of independent observations indicating that neutral air turbulence has caused PMWE. Ion density fluctuations show a turbulence spectrum within PMWE and no fluctuations outside. Temperature lapse rates close to the adiabatic gradient are observed in the vicinity of PMWE indicating persistent turbulent mixing. The spectral broadening of radar echoes is consistent with turbulent velocity fluctuations. Turbulence also explains the mean occurrence height of PMWE (~68?75 km): Viscosity increases rapidly with altitude and destroys any small scale fluctuations in the upper mesosphere, whereas electron densities are usually too low in the lower mesosphere to cause significant backscatter. The seasonal variation of echoes in the lower mesosphere is in agreement with a turbulence climatology derived from earlier sounding rocket flights. We have performed model calculations to study the absolute magnitude of backscatter from plasma fluctuations caused by neutral air turbulence. We find that volume reflectivities observed during PMWE are in quantitative agreement with theory. Apart from turbulence the most crucial requirement for PMWE is a sufficiently large number of electrons, for example produced by solar protons. We have studied the sensitivity of the radar echo strength on various parameters, most important ... Article in Journal/Newspaper Andøya Northern Norway Institut national des sciences de l'Univers: HAL-INSU Andøya ENVELOPE(13.982,13.982,68.185,68.185) Norway |
institution |
Open Polar |
collection |
Institut national des sciences de l'Univers: HAL-INSU |
op_collection_id |
ftinsu |
language |
English |
topic |
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere |
spellingShingle |
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere Lübken, F.-J. Strelnikov, B. Rapp, M. Singer, W. Latteck, R. Brattli, A. Hoppe, U.-P. Friedrich, M. The thermal and dynamical state of the atmosphere during polar mesosphere winter echoes |
topic_facet |
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere |
description |
International audience In January 2005, a total of 18 rockets were launched from the Andøya Rocket Range in Northern Norway (69° N) into strong VHF radar echoes called 'Polar Mesosphere Winter Echoes' (PMWE). The echoes were observed in the lower and middle mesosphere during large solar proton fluxes. In general, PMWE are much more seldom compared to their summer counterparts PMSE (typical occurrence rates at 69° N are 1?3% vs. 80%, respectively). Our in-situ measurements by falling sphere, chaff, and instrumented payloads provide detailed information about the thermal and dynamical state of the atmosphere and therefore allow an unprecedented study of the background atmosphere during PMWE. There are a number of independent observations indicating that neutral air turbulence has caused PMWE. Ion density fluctuations show a turbulence spectrum within PMWE and no fluctuations outside. Temperature lapse rates close to the adiabatic gradient are observed in the vicinity of PMWE indicating persistent turbulent mixing. The spectral broadening of radar echoes is consistent with turbulent velocity fluctuations. Turbulence also explains the mean occurrence height of PMWE (~68?75 km): Viscosity increases rapidly with altitude and destroys any small scale fluctuations in the upper mesosphere, whereas electron densities are usually too low in the lower mesosphere to cause significant backscatter. The seasonal variation of echoes in the lower mesosphere is in agreement with a turbulence climatology derived from earlier sounding rocket flights. We have performed model calculations to study the absolute magnitude of backscatter from plasma fluctuations caused by neutral air turbulence. We find that volume reflectivities observed during PMWE are in quantitative agreement with theory. Apart from turbulence the most crucial requirement for PMWE is a sufficiently large number of electrons, for example produced by solar protons. We have studied the sensitivity of the radar echo strength on various parameters, most important ... |
author2 |
Leibniz-Institute of Atmospheric Physics (AIP) Norwegian Defence Research Establishment (FFI) Institute of Communications Networks and Satellite Communications |
format |
Article in Journal/Newspaper |
author |
Lübken, F.-J. Strelnikov, B. Rapp, M. Singer, W. Latteck, R. Brattli, A. Hoppe, U.-P. Friedrich, M. |
author_facet |
Lübken, F.-J. Strelnikov, B. Rapp, M. Singer, W. Latteck, R. Brattli, A. Hoppe, U.-P. Friedrich, M. |
author_sort |
Lübken, F.-J. |
title |
The thermal and dynamical state of the atmosphere during polar mesosphere winter echoes |
title_short |
The thermal and dynamical state of the atmosphere during polar mesosphere winter echoes |
title_full |
The thermal and dynamical state of the atmosphere during polar mesosphere winter echoes |
title_fullStr |
The thermal and dynamical state of the atmosphere during polar mesosphere winter echoes |
title_full_unstemmed |
The thermal and dynamical state of the atmosphere during polar mesosphere winter echoes |
title_sort |
thermal and dynamical state of the atmosphere during polar mesosphere winter echoes |
publisher |
HAL CCSD |
publishDate |
2005 |
url |
https://hal.science/hal-00301733 https://hal.science/hal-00301733/document https://hal.science/hal-00301733/file/acpd-5-7613-2005.pdf |
long_lat |
ENVELOPE(13.982,13.982,68.185,68.185) |
geographic |
Andøya Norway |
geographic_facet |
Andøya Norway |
genre |
Andøya Northern Norway |
genre_facet |
Andøya Northern Norway |
op_source |
ISSN: 1680-7367 EISSN: 1680-7375 Atmospheric Chemistry and Physics Discussions https://hal.science/hal-00301733 Atmospheric Chemistry and Physics Discussions, 2005, 5 (4), pp.7613-7645 |
op_relation |
hal-00301733 https://hal.science/hal-00301733 https://hal.science/hal-00301733/document https://hal.science/hal-00301733/file/acpd-5-7613-2005.pdf |
op_rights |
info:eu-repo/semantics/OpenAccess |
_version_ |
1782329799044235264 |