H. Mavromichalaki et al., A POSSIBLE E-W ASYMMETRY OF THE CORONAL EMISSION-LINE INTENSITIES ANDK-CORONA BRIGHTNESS, Astrophysics and space science, 218(1), 1994, pp. 35-57
The analysis of the daily measurements of the coronal green and red li
ne intensities as well as the K-corona brightness, which have been col
lected by the Pic-du-Midi Observatory, for the time period 1944-1974,
has revealed some very interesting features. North-South (N-S) asymmet
ries for all these coronal intensities are confirmed again for this ti
me period. The main point of this analysis is a strong evidence of lon
gitudinal distribution of the coronal intensities as derived from the
data record. In our effort to confirm this asymmetry, we have examined
the yearly and monthly distribution of the asymmetry coefficient in e
ach solar quadrant showing that the northeast (NE) quadrant appears th
e most active of all. We have also examined the intensity ratios measu
red at the East and West solar limbs which is continuously greater tha
n the unit. A seasonal variation of this ratio has also been reported
with a maximum during the winter period and a minimum during the summe
r period.