The thermal and dynamical state of the atmosphere during polar mesosphere winter echoes
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...
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ftleibnizopen:oai:oai.leibnizopen.de:8-9q6YoBg80Wlv18Q3Jn 2023-10-29T02:30:07+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. 2006 application/pdf https://doi.org/10.34657/1352 https://oa.tib.eu/renate/handle/123456789/779 eng eng München : European Geopyhsical Union CC BY-NC-SA 2.5 Unported https://creativecommons.org/licenses/by-nc-sa/2.5/ Atmospheric Chemistry and Physics, Volume 6, Issue 1, Page 13-24 in situ measurement mesosphere thermodynamic property turbulence 550 article Text 2006 ftleibnizopen https://doi.org/10.34657/1352 2023-10-01T23:11:38Z 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 occur 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 radar 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 proton events. We have studied the sensitivity of the radar echo strength on various parameters, most important electron number density and turbulence ... Article in Journal/Newspaper Andøya Northern Norway LeibnizOpen (The Leibniz Association) |
institution |
Open Polar |
collection |
LeibnizOpen (The Leibniz Association) |
op_collection_id |
ftleibnizopen |
language |
English |
topic |
in situ measurement mesosphere thermodynamic property turbulence 550 |
spellingShingle |
in situ measurement mesosphere thermodynamic property turbulence 550 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 |
in situ measurement mesosphere thermodynamic property turbulence 550 |
description |
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 occur 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 radar 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 proton events. We have studied the sensitivity of the radar echo strength on various parameters, most important electron number density and turbulence ... |
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 |
München : European Geopyhsical Union |
publishDate |
2006 |
url |
https://doi.org/10.34657/1352 https://oa.tib.eu/renate/handle/123456789/779 |
genre |
Andøya Northern Norway |
genre_facet |
Andøya Northern Norway |
op_source |
Atmospheric Chemistry and Physics, Volume 6, Issue 1, Page 13-24 |
op_rights |
CC BY-NC-SA 2.5 Unported https://creativecommons.org/licenses/by-nc-sa/2.5/ |
op_doi |
https://doi.org/10.34657/1352 |
_version_ |
1781054622973034496 |