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首页> 外文期刊>Journal of Geophysical Research, A. Space Physics: JGR >Observations of GW/TID oscillations in the F2 layer at low latitude during high and low solar activity, geomagnetic quiet and disturbed periods
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Observations of GW/TID oscillations in the F2 layer at low latitude during high and low solar activity, geomagnetic quiet and disturbed periods

机译：观察千瓦/ F2 TID振荡层在低纬度高和低的太阳能活动,地磁宁静而不安的时期

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摘要

Ionospheric vertical sounding observations, using a digital ionosonde, are being carried out on a routine basis at Sao Jose dos Campos (23.2°S, 45.9°W; dip latitude 17.6°S, hereafter referred to as SJC), Brazil, located under the southern crest of the equatorial ionization anomaly (EIA), since August 2000. In this paper, we present and discuss the seasonal variation of gravity wave (GW) and traveling ionospheric disturbance (TID) oscillations in the ionospheric F2 layer during high solar activity (HSA, September 2000 to August 2001) and low solar activity (LSA, January 2006 to December 2006) observed at SJC during different levels of geomagnetic activity. The GW/TID signatures in the F2 layer can be seen in the isofrequency lines of virtual height daily variations for six fixed frequencies (3, 4, 5, 6, 7, and 8 MHz) which show quasiperiodic oscillations (crests and valleys). The crests and valleys when seen in close frequencies present a phase difference (i.e., first it is observed at higher frequency then at lower frequency), indicating a downward phase velocity. These quasiperiodic oscillations induced in the virtual heights are divided into three groups as small amplitude (lower than 40 km), medium amplitude (between 40 km and 60 km), and large amplitude (greater than 60 km). The observations show that GWs/TIDs are much more pronounced at F layer heights during HSA than LSA and the large-amplitude GWs/TIDs are present normally only during HSA.
机译：电离层垂直探测观察,使用数字ionosonde,正在进行经常在圣荷西dos坎波斯(23.2°,45.9°W;SJC),巴西,坐落在南部嵴的赤道电离异常(EIA),2000年8月以来。讨论了重力波的季节性变化旅行(GW)和电离层扰动(TID)振动在电离层F2层高的太阳活动(HSA, 2000年9月2001年8月)和低太阳活动(LSA,一月2006年到2006年12月)观察在SJC不同级别的地磁活动。千瓦/ TID签名F2层中可以看到每天等频率虚拟线的高度变化6固定频率(3、4、5、6、图7和图8 MHz),表明准周期的振荡(波峰和波谷)。山谷,当看到密切频率呈现出相位差(即第一次观察到更高的频率较低频率),显示一个向下的相速度。准周期的振荡诱导在虚拟小山庄分为三组振幅(低于40公里),中等振幅(40公里至60公里),大的振幅(大于60公里)。千瓦/ tid在F层更明显在比LSA HSA和高度为大幅度千瓦/ tid正常存在只有在保险公司。

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