 |
| Titel |
Polar mesosphere summer echo strength in relation to solar variability and geomagnetic activity during 1997–2009 |
| VerfasserIn |
M. Smirnova, E. Belova, S. Kirkwood  |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
0992-7689
|
| Digitales Dokument |
URL |
| Erschienen |
In: Annales Geophysicae ; 29, no. 3 ; Nr. 29, no. 3 (2011-03-16), S.563-572 |
| Datensatznummer |
250016992
|
| Publikation (Nr.) |
 copernicus.org/angeo-29-563-2011.pdf |
|
|
|
|
|
| Zusammenfassung |
| This paper is based on measurements of Polar Mesosphere Summer Echoes (PMSE)
with the 52 MHz radar ESRAD, located near Kiruna, in Northern Sweden, during
the summers of 1997–2009. Here, a new independent calibration method
allowing estimation of possible changes in antenna feed losses and
transmitter output is described and implemented for accurate calculation of
year-to-year variations of PMSE strength (expressed in absolute units –
radar volume reflectivity η). The method is based on radar-radiosonde
comparisons in the upper troposphere/lower stratosphere region
simultaneously with PMSE observations. Inter-annual variations of PMSE
volume reflectivity are found to be strongly positively correlated with the
local geomagnetic K-index, both when averaged over all times of the day, and
when considering 3-h UT intervals separately. Increased electron density
due to energetic particle precipitation from the magnetosphere is suggested
as one of the possible reasons for such a correlation. Enhanced ionospheric
electric field may be another reason but this requires further study.
Multi-regression analysis of inter-annual variations of PMSE η shows also an
anti-correlation with solar 10.7 cm flux and the absence of any
statistically significant trend in PMSE strength over the interval
considered (13-years). Variations related to solar flux and K-index account
for 86% of the year-to-year variations in radar volume reflectivity. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|