 |
| Titel |
Electrojet control of ambient ionization near the crest of the equatorial anomaly in the Indian zone |
| VerfasserIn |
S. K. Chakraborty, R. Hajra |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
0992-7689
|
| Digitales Dokument |
URL |
| Erschienen |
In: Annales Geophysicae ; 27, no. 1 ; Nr. 27, no. 1 (2009-01-06), S.93-105 |
| Datensatznummer |
250016358
|
| Publikation (Nr.) |
 copernicus.org/angeo-27-93-2009.pdf |
|
|
|
|
|
| Zusammenfassung |
| A long-term (1978–1990) database of total electron content (TEC) from a
location (Calcutta: 22.58° N, 88.38° E geographic, dip:
32° N)
near the northern crest of the equatorial ionization anomaly has
extensively been studied to characterize the contribution of fountain effect
in the maintenance of ambient ionization. The equatorial electrojet (EEJ)
data obtained from ground magnetometer recording are used to assess the
contribution of equatorial fountain. Analysis made with instantaneous
values, day's maximum values and time-integrated values of EEJ strength
exhibit more or less similar features. When instantaneous values of EEJ are
considered TEC variations exhibit two maxima in correlation, one around
10:00–12:00 IST and the other around 18:00–20:00 IST. The later maximum in
correlation coefficient is conspicuously absent when integrated values of
EEJ are considered. An impulse-like feature is reflected in the diurnal TEC
variation during the time intervals (09:00–10:00 IST) and (18:00–19:00 IST).
The statistical analysis reveals greater correspondence with high
level of significance between diurnal TEC and EEJ in the descending epoch of
solar cycle than in the ascending one. On the seasonal basis, TEC in the
summer solstitial months are observed to be more sensitive to the changes in
EEJ strength than in the equinoctial and winter solstitial months. Combining
the effects of solar flux, season, local time and EEJ an empirical formula
for monthly mean diurnal TEC has been developed and validated using observed
TEC data. An estimation of the relative contributions of the several terms
appearing in the formula reveals much more solar flux contribution (~50–70%)
in the maintenance of ambient ionization around the present
location than the EEJ effects (maximum~20%). |
| |
|
| Teil von |
|
|
|
|
|
|
|
|