Kerime AKSAÇ, İbrahim ÜNAL, Erdinç TİMOÇİN

YÜKSEK ENLEM foF2 DEĞERLERİNDEKİ DEĞİŞİMLERİN JEOMANYETİK AKTİVİTEYE BAĞLILIĞI

Bu çalışmada, Aralık 1971-Eylül 1972 tarihleri arasında yüksek enlem bölgesi olarak tanımlanan 60o-90o değişmeyen manyetik enlem arasındaki 7 iyonsonda istasyonundan alınan saatlik foF2 verilerinin değişmeyen manyetik enleme göre değişimleri, farklı jeomanyetik aktivite durumları için incelenmiştir. Analizlerden elde edilen sonuçlara göre, gündüz saatlerindeki foF2 değerlerinin, gece saatlerindeki değerlerden büyük olduğu, ayrıca bu saatlerde foF2 değerlerinin değişmeyen manyetik enlem artışı ile 68o-72o değişmeyen manyetik enlemleri arasındaki artış dışında azaldığı tespit edilmiştir. Gece saatlerinde ise foF2 değerlerinin yaklaşık 66o-72o değişmeyen manyetik enlemleri arasında arttığı, bu enlemlerden daha büyük ve daha küçük enlemlerde ise foF2 değerlerinin azalarak çukura benzer bir yapı oluşturduğu gözlemlenmiştir. Ayrıca mevsimsel ve jeomanyetik aktivite değişimlerinin, foF2 değerlerinin enlemsel değişimleri üzerinde önemli bir etkiye sahip olduğu tespit edilmiştir. Jeomanyetik pasif durumdaki foF2 değerleri, jeomanyetik aktif durumdaki foF2 değerlerinden büyüktür. Özellikle jeomanyetik aktif durumdaki Aralık döneminde, polar cap ve polar oval bölgeleri daha belirgin ve bu bölgeler enlemsel olarak daha geniş bir yapıya sahiptir.

Anahtar Kelimeler:

Yüksek enlem iyonosferi, Manyetosfer, Jeomanyetik aktivite

THE DEPENDENCE ON THE GEOMAGNETIC ACTIVITY OF CHANGES IN THE foF2 VALUES AT THE HIGH LATITUDES

In this study, changes according to invariant magnetic latitude of the hourly foF2 data that are taken from seven ionosondes stations are situated at between 60o-90o invariant magnetic latitude as known high latitude region are investigated for different geomagnetic activity conditions during December 1971-September 1972. According to the results obtained from the analyzes, it was found that the foF2 values in the daytime are larger than those in the nighttime, and the foF2 values in these hours decreases with the increasing of the invariant magnetic latitude the except for between about 68o and 72o invariant magnetic latitude. At night time, it was observed that the foF2 values increases between about 66o and 72o invariant magnetic latitude, while the foF2 values exhibit a trough structure at larger and smaller latitudes than these latitudes. It is also observed that seasonal and geomagnetic activity changes have a significant influence on the latitudinal changes of the foF2 values. The foF2 values in the geomagnetic quiet condition are larger than the foF2 values in the geomagnetic active conduction. Especially in the geomagnetic active conduction of the December, the polar cap and polar oval zones are more prominent and have a larger latitudinal structure.

Keywords:

High latitude ionosphere Magnetosphere, Polar region, Geomagnetic activity,

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