|
|
 |
|
|
Ann. Geophys., 20, 539-545, 2002
www.ann-geophys.net/20/539/2002/
© European Geosciences Union 2002
Are variations in PMSE intensity affected by energetic particle precipitation?
V. Barabash1, S. Kirkwood1, and P. B. Chilson2
1Swedish Institute of Space Physics, Box 812, S-981-28 Kiruna, Sweden
2NOAA Environmental Technology Laboratory and Cooperative Institute for Research in the Environmental Sciences (CIRES), University of Colorado-NOAA, 325 Broadway, R/ET2, Boulder, CO 80305-3328, USA
Correspondence to: S. Kirkwood (sheila.kirkwood@irf.se)
Abstract. The correlation between
variations in Polar Mesosphere Summer Echoes (PMSE) and variations in energetic
particle precipitation is examined. PMSE were observed by the Esrange VHF MST
Radar (ESRAD) at 67°53' N, 21°06' E. The 30 MHz riometer in Abisko (68°24'
N, 18°54' E) registered radio wave absorption caused by ionization changes in
response to energetic particle precipitation. The relationship between the
linear PMSE intensity and the square of absorption has been estimated using the
Pearson linear correlation and the Spearman rank correlation. The mean diurnal
variation of the square of absorption and the linear PMSE intensity are highly
correlated. However, their day-to-day variations show significant correlation
only during the late evening hours. The correlation in late evening does not
exceed 0.6. This indicates that varying ionization cannot be considered as a
primary source of varying PMSE, and the high correlation found when mean
diurnal variations are compared is likely a by-product of daily variations
caused by other factors.
Key words. Ionosphere (particle
precipitation) Magnetospheric physics (energetic particles, precipitating)
Meteorology and atmospheric dynamics (precipitation)
Full Article in PDF (283 KB) |
|
|
