Climatologies of nighttime upper thermospheric winds measured by ground-based Fabry-Perot interferometers during geomagnetically quiet conditions: 2. High-latitude circulation and interplanetary magnetic field dependence
We analyze upper thermospheric (similar to 250 km) nighttime horizontal neutral wind patterns, during geomagnetically quiet (Kp <3) conditions, over the following locations: South Pole (90 degrees S), Halley (76 degrees S, 27 degrees W), Millstone Hill (43 degrees N, 72 degrees W), Sondre Stromfj...
Main Authors: | , , , , , |
---|---|
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
2006
|
Subjects: | |
Online Access: | https://orbit.dtu.dk/en/publications/6ea904f1-ea0d-48bd-a6a5-73113fbc59bc |
id |
ftdtupubl:oai:pure.atira.dk:publications/6ea904f1-ea0d-48bd-a6a5-73113fbc59bc |
---|---|
record_format |
openpolar |
spelling |
ftdtupubl:oai:pure.atira.dk:publications/6ea904f1-ea0d-48bd-a6a5-73113fbc59bc 2024-01-14T10:10:41+01:00 Climatologies of nighttime upper thermospheric winds measured by ground-based Fabry-Perot interferometers during geomagnetically quiet conditions: 2. High-latitude circulation and interplanetary magnetic field dependence Emmert, J.T. Hernandez, G. Jarvis, M.J. Niciejewski, R.J. Sipler, D.P. Vennerstrøm, Susanne 2006 https://orbit.dtu.dk/en/publications/6ea904f1-ea0d-48bd-a6a5-73113fbc59bc eng eng https://orbit.dtu.dk/en/publications/6ea904f1-ea0d-48bd-a6a5-73113fbc59bc info:eu-repo/semantics/restrictedAccess Emmert , J T , Hernandez , G , Jarvis , M J , Niciejewski , R J , Sipler , D P & Vennerstrøm , S 2006 , ' Climatologies of nighttime upper thermospheric winds measured by ground-based Fabry-Perot interferometers during geomagnetically quiet conditions: 2. High-latitude circulation and interplanetary magnetic field dependence ' , Journal of Geophysical Research-space Physics , vol. 111 , no. A12 . article 2006 ftdtupubl 2023-12-20T23:56:25Z We analyze upper thermospheric (similar to 250 km) nighttime horizontal neutral wind patterns, during geomagnetically quiet (Kp <3) conditions, over the following locations: South Pole (90 degrees S), Halley (76 degrees S, 27 degrees W), Millstone Hill (43 degrees N, 72 degrees W), Sondre Stromfjord (67 degrees N, 51 degrees W), and Thule (77 degrees N, 68 degrees W). We examine the wind patterns as a function of magnetic local time and latitude, solar cycle, day of year, and the dawn-dusk and north-south components of the interplanetary magnetic field (IMF B-y and B-z). In magnetic coordinates, the quiet time high-latitude wind patterns are dominated by antisunward flow over the polar cap, with wind speeds that generally increase with increasing solar extreme ultraviolet (EUV) irradiation. The winds are generally stronger during equinox than during winter, particularly over the South Pole in the direction of eastern longitudes. IMF By exerts a strong influence on the wind patterns, particularly in the midnight sector. During winter, By positive winds around midnight in the northern ( southern) hemisphere are directed more toward the dusk (dawn) sector, compared to corresponding By negative winds; this behavior is consistent with the By-dependence of statistical ionospheric convection patterns. The strength of the wind response to By tends to increase with increasing solar EUV irradiation, roughly in proportion to the increased wind speeds. Quiet time By effects are detectable at latitudes as low as that of Millstone Hill ( magnetic latitude 53 degrees N). Quiet time Bz effects are negligible except over the magnetic polar cap station of Thule. Article in Journal/Newspaper Sondre Stromfjord South pole Technical University of Denmark: DTU Orbit South Pole |
institution |
Open Polar |
collection |
Technical University of Denmark: DTU Orbit |
op_collection_id |
ftdtupubl |
language |
English |
description |
We analyze upper thermospheric (similar to 250 km) nighttime horizontal neutral wind patterns, during geomagnetically quiet (Kp <3) conditions, over the following locations: South Pole (90 degrees S), Halley (76 degrees S, 27 degrees W), Millstone Hill (43 degrees N, 72 degrees W), Sondre Stromfjord (67 degrees N, 51 degrees W), and Thule (77 degrees N, 68 degrees W). We examine the wind patterns as a function of magnetic local time and latitude, solar cycle, day of year, and the dawn-dusk and north-south components of the interplanetary magnetic field (IMF B-y and B-z). In magnetic coordinates, the quiet time high-latitude wind patterns are dominated by antisunward flow over the polar cap, with wind speeds that generally increase with increasing solar extreme ultraviolet (EUV) irradiation. The winds are generally stronger during equinox than during winter, particularly over the South Pole in the direction of eastern longitudes. IMF By exerts a strong influence on the wind patterns, particularly in the midnight sector. During winter, By positive winds around midnight in the northern ( southern) hemisphere are directed more toward the dusk (dawn) sector, compared to corresponding By negative winds; this behavior is consistent with the By-dependence of statistical ionospheric convection patterns. The strength of the wind response to By tends to increase with increasing solar EUV irradiation, roughly in proportion to the increased wind speeds. Quiet time By effects are detectable at latitudes as low as that of Millstone Hill ( magnetic latitude 53 degrees N). Quiet time Bz effects are negligible except over the magnetic polar cap station of Thule. |
format |
Article in Journal/Newspaper |
author |
Emmert, J.T. Hernandez, G. Jarvis, M.J. Niciejewski, R.J. Sipler, D.P. Vennerstrøm, Susanne |
spellingShingle |
Emmert, J.T. Hernandez, G. Jarvis, M.J. Niciejewski, R.J. Sipler, D.P. Vennerstrøm, Susanne Climatologies of nighttime upper thermospheric winds measured by ground-based Fabry-Perot interferometers during geomagnetically quiet conditions: 2. High-latitude circulation and interplanetary magnetic field dependence |
author_facet |
Emmert, J.T. Hernandez, G. Jarvis, M.J. Niciejewski, R.J. Sipler, D.P. Vennerstrøm, Susanne |
author_sort |
Emmert, J.T. |
title |
Climatologies of nighttime upper thermospheric winds measured by ground-based Fabry-Perot interferometers during geomagnetically quiet conditions: 2. High-latitude circulation and interplanetary magnetic field dependence |
title_short |
Climatologies of nighttime upper thermospheric winds measured by ground-based Fabry-Perot interferometers during geomagnetically quiet conditions: 2. High-latitude circulation and interplanetary magnetic field dependence |
title_full |
Climatologies of nighttime upper thermospheric winds measured by ground-based Fabry-Perot interferometers during geomagnetically quiet conditions: 2. High-latitude circulation and interplanetary magnetic field dependence |
title_fullStr |
Climatologies of nighttime upper thermospheric winds measured by ground-based Fabry-Perot interferometers during geomagnetically quiet conditions: 2. High-latitude circulation and interplanetary magnetic field dependence |
title_full_unstemmed |
Climatologies of nighttime upper thermospheric winds measured by ground-based Fabry-Perot interferometers during geomagnetically quiet conditions: 2. High-latitude circulation and interplanetary magnetic field dependence |
title_sort |
climatologies of nighttime upper thermospheric winds measured by ground-based fabry-perot interferometers during geomagnetically quiet conditions: 2. high-latitude circulation and interplanetary magnetic field dependence |
publishDate |
2006 |
url |
https://orbit.dtu.dk/en/publications/6ea904f1-ea0d-48bd-a6a5-73113fbc59bc |
geographic |
South Pole |
geographic_facet |
South Pole |
genre |
Sondre Stromfjord South pole |
genre_facet |
Sondre Stromfjord South pole |
op_source |
Emmert , J T , Hernandez , G , Jarvis , M J , Niciejewski , R J , Sipler , D P & Vennerstrøm , S 2006 , ' Climatologies of nighttime upper thermospheric winds measured by ground-based Fabry-Perot interferometers during geomagnetically quiet conditions: 2. High-latitude circulation and interplanetary magnetic field dependence ' , Journal of Geophysical Research-space Physics , vol. 111 , no. A12 . |
op_relation |
https://orbit.dtu.dk/en/publications/6ea904f1-ea0d-48bd-a6a5-73113fbc59bc |
op_rights |
info:eu-repo/semantics/restrictedAccess |
_version_ |
1788065467445805056 |