Time dependence of average structure size and precipitation energy in pulsating aurora
Pulsating aurora is low intensity aurora appearing in limited structures with quasiperiodicalmodulations in intensity. The highly energetic electron precipitation associatedwith pulsating aurora has been shown to cause chemical changes as far downas the mesosphere, causing ozone depletion. The drive...
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KTH, Rymd- och plasmafysik
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ftkthstockholm:oai:DiVA.org:kth-211561 2023-05-15T16:12:08+02:00 Time dependence of average structure size and precipitation energy in pulsating aurora Bolmgren, Karl 2017 application/pdf http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-211561 eng eng KTH, Rymd- och plasmafysik TRITA-EE, 1653-5146 2017:084 http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-211561 info:eu-repo/semantics/openAccess Electrical Engineering Electronic Engineering Information Engineering Elektroteknik och elektronik Student thesis info:eu-repo/semantics/bachelorThesis text 2017 ftkthstockholm 2022-08-11T12:40:56Z Pulsating aurora is low intensity aurora appearing in limited structures with quasiperiodicalmodulations in intensity. The highly energetic electron precipitation associatedwith pulsating aurora has been shown to cause chemical changes as far downas the mesosphere, causing ozone depletion. The drivers involved in generating pulsatingaurora are not fully known, and efforts have been made to model many of thesuggested mechanisms. In order to evaluate these results observational constraintson the temporal and spatial characteristics of pulsating aurora are necessary.Previous studies have noted that the pulsating area tends to decrease over timefrom studying single pulsating patches. This study examines a large set of all-skycamera data comprising approximately 400 image series with pulsating aurora fromthe MIRACLE network in northern Fennoscandia in order to determine the time dependenceof the average size and precipitation energy in pulsating aurora. The 20 stime resolution of the all-sky images makes it challenging to identify spatial boundariesof the pulsating structures whose periods have a typical range of 2-20 s. Twomethods are implemented here, with the same results showing a gradual decreasein average size. No relationship between UT and size is clear. The electron precipitationenergies are inferred from the peak emission height and 557,7 nm/427,8 nmintensity ratio, and seem not to be directly related pulsating structure size. Thepeak emission height shows a constant average energy following an initial increasefollowing the onset of the pulsating aurora, and the intensity ratio suggests a constantaverage electron precipitation energy. Pulserande norrsken är ett ljussvagt norrsken som framträder i begränsade strukturermed kvasiperiodiska intensitetsförändringar. De nedfallande högenergetiskaelektronerna som är associerade med pulserande norrsken har visats påverka ozonkoncentrationeni mesosfären. De mekanismer som ligger bakom pulserande norrskenär inte fullständigt kända, och försök har gjorts för att ... Bachelor Thesis Fennoscandia Royal Institute of Technology, Stockholm: KTHs Publication Database DiVA |
institution |
Open Polar |
collection |
Royal Institute of Technology, Stockholm: KTHs Publication Database DiVA |
op_collection_id |
ftkthstockholm |
language |
English |
topic |
Electrical Engineering Electronic Engineering Information Engineering Elektroteknik och elektronik |
spellingShingle |
Electrical Engineering Electronic Engineering Information Engineering Elektroteknik och elektronik Bolmgren, Karl Time dependence of average structure size and precipitation energy in pulsating aurora |
topic_facet |
Electrical Engineering Electronic Engineering Information Engineering Elektroteknik och elektronik |
description |
Pulsating aurora is low intensity aurora appearing in limited structures with quasiperiodicalmodulations in intensity. The highly energetic electron precipitation associatedwith pulsating aurora has been shown to cause chemical changes as far downas the mesosphere, causing ozone depletion. The drivers involved in generating pulsatingaurora are not fully known, and efforts have been made to model many of thesuggested mechanisms. In order to evaluate these results observational constraintson the temporal and spatial characteristics of pulsating aurora are necessary.Previous studies have noted that the pulsating area tends to decrease over timefrom studying single pulsating patches. This study examines a large set of all-skycamera data comprising approximately 400 image series with pulsating aurora fromthe MIRACLE network in northern Fennoscandia in order to determine the time dependenceof the average size and precipitation energy in pulsating aurora. The 20 stime resolution of the all-sky images makes it challenging to identify spatial boundariesof the pulsating structures whose periods have a typical range of 2-20 s. Twomethods are implemented here, with the same results showing a gradual decreasein average size. No relationship between UT and size is clear. The electron precipitationenergies are inferred from the peak emission height and 557,7 nm/427,8 nmintensity ratio, and seem not to be directly related pulsating structure size. Thepeak emission height shows a constant average energy following an initial increasefollowing the onset of the pulsating aurora, and the intensity ratio suggests a constantaverage electron precipitation energy. Pulserande norrsken är ett ljussvagt norrsken som framträder i begränsade strukturermed kvasiperiodiska intensitetsförändringar. De nedfallande högenergetiskaelektronerna som är associerade med pulserande norrsken har visats påverka ozonkoncentrationeni mesosfären. De mekanismer som ligger bakom pulserande norrskenär inte fullständigt kända, och försök har gjorts för att ... |
format |
Bachelor Thesis |
author |
Bolmgren, Karl |
author_facet |
Bolmgren, Karl |
author_sort |
Bolmgren, Karl |
title |
Time dependence of average structure size and precipitation energy in pulsating aurora |
title_short |
Time dependence of average structure size and precipitation energy in pulsating aurora |
title_full |
Time dependence of average structure size and precipitation energy in pulsating aurora |
title_fullStr |
Time dependence of average structure size and precipitation energy in pulsating aurora |
title_full_unstemmed |
Time dependence of average structure size and precipitation energy in pulsating aurora |
title_sort |
time dependence of average structure size and precipitation energy in pulsating aurora |
publisher |
KTH, Rymd- och plasmafysik |
publishDate |
2017 |
url |
http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-211561 |
genre |
Fennoscandia |
genre_facet |
Fennoscandia |
op_relation |
TRITA-EE, 1653-5146 2017:084 http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-211561 |
op_rights |
info:eu-repo/semantics/openAccess |
_version_ |
1765997380389306368 |