中低纬电离层F2区峰值参量周年和半年变化及电场影响模拟研究

利用二维电离层理论模式,在地磁平静和太阳活动低年的情况下,模拟中低纬电离层峰值电子浓度NmF2和峰值高度hmF2的周年和半年变化规律.在考虑与不考虑理论模式输入电场的周年和半年变化两种情况下,对比分析研究了电场对电离层NmF2和hmF2周年和半年变化的影响.结果表明,当输入电场没有周年和半年变化分量时,模拟NmF2表现出一定的半年变化特征,而hmF2周年变化分量较强;当输入电场包含了周年和半年变化特征时,模拟NmF2和hmF2周年和半年变化特征明显改变,且这种改变随地方时和地磁纬度不同有较大的差别;电场对NmF2半年变化的影响无论是在强度还是范围上都明显大干对hmF2的影响,电场对NmF2的影响在赤道和驼峰区都比较明显,但对hmF2的影响主要集中在地磁赤道区.通过对比模拟NmF2和hmF2发现,中低纬电离层hmF2与NmF2半年变化具有一定的相关性,初步分析认为电离层电场及其关的"赤道喷泉"效应可能是这种相关性的重要纽带;电离层电场对hmF2半年变化的影响仅局限在地磁赤道地区,而对NmF2影响可达驼峰地区,因此hmF2与NmF2半年变化的相关性也仅在地磁赤道较为明显.

Simulation of the Annual and Semi-annual Variation of F2 Region Ionosphere at Mid-and Low-latitudes

With a theoretical ionosphere model,the annual and semi-annual variations of NmF2 and hmF2 at F2 region are simulated at mid-and low-latitudes under low solar and geomagnetic activities.The influence of electric fields on NmF2 and hmF2 are analyzed with the annual and semi-annual variations of electric fields included.The results show that the simulated NmF2 sees a semi-annual variation and hmF2 sees an annual variation while the input electric field shows neither semi-annual nor annual variation.The simulated NmF2 and hmF2 annual and semi-annual variations would be much different when the input electric field shows annual and semi-annual variations.Further investigations show that the electric field has greater influence on NmF2 than on hmF2,and for NmF2 the influence shows both at the equatorial and hump region ionosphere,while for hmF2 the influence shows onlty at the equatorial ionosphere.