 |
| Titel |
Diurnal, seasonal, latitudinal and solar cycle variation of electron temperature in the topside F-region of the Indian zone ionosphere |
| VerfasserIn |
M. Chamua, P. K. Bhuyan, P. Subrahmanyam, S. C. Garg |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
0992-7689
|
| Digitales Dokument |
URL |
| Erschienen |
In: Annales Geophysicae ; 25, no. 9 ; Nr. 25, no. 9 (2007-10-02), S.1995-2006 |
| Datensatznummer |
250015914
|
| Publikation (Nr.) |
 copernicus.org/angeo-25-1995-2007.pdf |
|
|
|
|
|
| Zusammenfassung |
| Electron temperature Te observed by the SROSS C2 satellite at equatorial
and low latitudes during the low to high solar activity period of 1995–2001
at the height of ~500 km is investigated in terms of local time,
season, latitude, solar sunspot number Rz and F10.7 cm solar flux. The
satellite covered the latitude belt of 31° S–34° N and the
longitude range of 40°–100° E. The average nighttime (20:00–04:00 LT)
Te varies between 750–1200 K and then rises sharply in the
sunrise period (04:00–06:00 LT) to the morning high from 07:00 to
10:00 LT and attains a daytime (10:00–14:00 LT) average of 1100–2300 K. The
morning enhancement is more pronounced in the equinoxes. A secondary
maximum in Te is also observed around 16:00–18:00 LT in the June solstice
and in the equinoxes. Daytime electron temperature was found to be higher in
autumn compared to that in spring in all latitudes. Between the solstices,
the amplitude of the morning enhancement is higher in winter compared to
that in summer. Both day and nighttime Te observed by the SROSS C2
satellite bears a positive correlation with solar activity when averaged on
a shorter time scale, i.e. over the period of a month. But on a longer time
scale, i.e. averaged over a year, the daytime electron temperature gradually
decreases from 1995 till it reaches the minimum value in 1997, after which
Te again continues to rise till 2001. The variations are distinctly seen
in summer and in the equinoxes. The sunspot activity during solar cycle 23 was
minimum in 1996 and maximum in 2000. Annual average electron temperature,
therefore, appears to follow the variation of solar activity with a time lag
of about one year, both at the bottom and top of solar cycle 23, indicating an
inherent inertia of the ionosphere thermosphere regime to variations in
solar flux. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|