 |
| Titel |
Polar mesosphere summer echoes during the July 2000 solar protonevent |
| VerfasserIn |
V. Barabash, S. Kirkwood  , A. Feofilov, A. Kutepov |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
0992-7689
|
| Digitales Dokument |
URL |
| Erschienen |
In: Annales Geophysicae ; 22, no. 3 ; Nr. 22, no. 3 (2004-03-19), S.759-771 |
| Datensatznummer |
250014800
|
| Publikation (Nr.) |
 copernicus.org/angeo-22-759-2004.pdf |
|
|
|
|
|
| Zusammenfassung |
| The influence of the solar proton event (SPE) 14–16 July 2000 on Polar
Mesosphere Summer Echoes (PMSE) is examined. PMSE were observed by the Esrange
VHF MST Radar (ESRAD) at 67°53'N, 21°06'E. The 30MHz Imaging Riometer for
Ionospheric Studies IRIS in Kilpisjärvi (69°30'N, 20°47'E) registered cosmic radio noise
absorption caused by ionisation changes in response to the energetic particle
precipitation. An energy deposition/ion-chemical model was used to estimate the
density of free electrons and ions in the upper atmosphere. Particle collision frequencies
were calculated from the MSISE-90 model. Electric fields were calculated using
conductivities from the model and measured magnetic disturbances. The electric field
reached a maximum of 91mV/m during the most intensive period of the geomagnetic
storm accompanying the SPE. The temperature increase due to Joule and particle heating
was calculated, taking into account radiative cooling. The temperature increase at PMSE
heights was found to be very small.
The observed PMSE were rather intensive and extended over the 80–90km height
interval. PMSE almost disappeared above 86km at the time of greatest Joule heating on
15 July 2000. Neither ionisation changes, nor Joule/particle heating can explain the PMSE
reduction. Transport effects due to the strong electric field are a more likely explanation.
Key words. Meteorology and atmospheric dynamics (middle
atmospheric dynamics), ionosphere (ionospheric disturbances;
solar radiation and cosmic ray effects) |
| |
|
| Teil von |
|
|
|
|
|
|
|
|