夜间f_0F_2存在季节异常现象

There is Seasonal Abnormal Phenomenon in Night Time f_0F_2

本文用1975.12—1986.12我国9个电离层站的资料分析得出,在一定的纬度和太阳活动条件下,夜间f_0F_2存在季节异常现象.夜间季节异常现象具有两个明显的特点:只有低纬才具有夜间季节异常特征;太阳活动高年夜间季节异常的程度增加.夜间季节异常是白天f_0F_2季节异常现象的延续,夏半球至冬半球的大气流动造成的中性气体浓度比(O/O_2和O/N_2)的季节变化,是形成f_0F_2季节异常的根本原因.并初步分析了夜间季节异常的低纬局限性及随太阳活动变化的成因.

Using data of nine ionospheric stations of China during Dec., 1975-Dec., 1986, it is presented that under the conditions of certain latitudes and solar activity, night time f0F2 shows a seasonal anomaly similar to that of the daytime foFz. This anomaly obviously shows two features: it only occurs in low latitudes; the higher solar activity is, the larger exlent of the degree of the anomaly is to. The night time seasonal abnormal phenomenon is the continuation of daytime seasonal abnormal phenomenon. The promary mechanism of the phenomenon is the seasonal variation of neutral air (O, O2, N2) concentration ratio O/O2 and O/Nz, caused by the summer hemispher to winter hemisphere air flow. It is analysed why the night time seasonal abnormal phenomenon is limited in low latitudes and why the abnormal degree changes with solar activity.