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Influence of Atmospheric Circulation on Orientation of Auroral Arcs

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posted on 2025-03-24, 15:41 authored by A Kozlovsky, M Myllymaa, R Lukianova, T Raita, Mark LesterMark Lester

We investigated statistically the orientation of about 10,000 auroral arcs observed during 2016–2021 in Abisko (68.36°N, 18.81°E, Sweden) in the equatorward part of the nightside auroral oval. The observations were made between 19 and 06 magnetic local time (MLT). On average, the orientation of the arcs, that is, the angle between an arc and the West‐East direction, linearly changed with MLT at the rate 2.2°/hr. In most cases the mean orientation of the auroral arcs near midnight was parallel to the geomagnetic latitude of Abisko, except a few late winter or spring months. These anomalies cannot be explained by geomagnetic disturbances or interplanetary conditions. They do, however, coincide with spring transitions in the atmospheric circulations from winter‐to summer‐type. The spring transitions were manifested in the data of a meteor radar in the region of observations as reversals of the zonal wind at altitudes 90–100 km from eastward to westward. We propose that these spring transition changes in the global atmospheric circulation couple also the overlying thermosphere at 100–150 km where neutral winds may affect the ionosphere and subsequently the whole ionosphere‐magnetosphere system. Then, changes in the coupled ionosphere‐magnetosphere system are manifested in changes of the orientation of auroral arcs.

Funding

Academy of Finland. Grant Number: 339849

A Consolidated Grant Proposal for Solar and Planetary Science at the University of Leicester, 2019 - 2022

Science and Technology Facilities Council

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History

Author affiliation

College of Science & Engineering Physics & Astronomy

Version

  • VoR (Version of Record)

Published in

Journal of Geophysical Research: Space Physics

Volume

128

Issue

7

Publisher

American Geophysical Union (AGU)

issn

2169-9380

eissn

2169-9402

Copyright date

2023

Available date

2025-03-24

Language

en

Deposited by

Professor Mark Lester

Deposit date

2025-03-20

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