Global Positioning System measurements of the ionospheric zonal apparent velocity at Cachoeira Paulista in Brazil
Global Positioning System measurements of the ionospheric zonal apparent velocity at Cachoeira Paulista in Brazil
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DOI：
10.1029/1999ja000244
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发表时间：
2000-03
影响因子：
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通讯作者：
H. Kil;P. Kintner;E. D. de Paula;I. J. Kantor
中科院分区：
文献类型：
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作者：
H. Kil;P. Kintner;E. D. de Paula;I. J. Kantor
1998年11月6日至19日期间，在巴西的卡舒埃拉保利斯塔（南纬22.41°，西经45.00°，倾角-26 °）利用全球定位系统的测量结果对电离层不规则性及其纬向视漂移进行了研究。使用四个沿地磁方向东西和南北分布的GPS接收器监测GPS L1频率（1.575 GHz）的无线电闪烁。通过GPS L1和L2（1.227 GHz）阶段的电离层推进测量总电子含量。强烈的振幅振荡与TEC波动相一致，TEC波动与沿着磁场延伸的F气泡有关。运动的Presnel尺度（400米）电离层不规则层造成的闪烁漂移，并使用互相关技术测量其纬向视漂移速度。我们的测量结果表明，在2000 LT时，视向东的速度在200 ~ 150 m/s之间变化，然后在午夜时减小到100-50 m/s。在一个磁干扰的一天，逆转的纬向表观漂移观察到午夜后不久，和在清晨观察到的向西的视速度显示在天空中的位置有很大的变化。从接收器间隔在地磁南北方向，我们测量了近零的时间偏移，从我们得出的结论是，几百米规模的不规则性的相关长度远大于70米的南北接收器之间的分离。
Ionospheric irregularities and their zonal apparent drift were studied using Global Positioning System (GPS) measurements at Cachoeira Paulista (22.41°S, 45.00°W, −26° dip angle) in Brazil during November 6–19, 1998. Radio scintillations at the GPS L1 frequency (1.575 GHz) were monitored using four GPS receivers spaced geomagnetically east–west and north–south. Total electron content (TEC) was measured through the ionospheric advance of the GPS L1 and L2 (1.227 GHz) phases. Strong amplitude scintillations coincided with TEC fluctuations associated with spread F bubbles elongated along the magnetic field. Movement of the Presnel-scale (400 m) ionospheric irregularity layers caused the scintillation to drift, and their zonal apparent drift velocities were measured using a cross-correlation technique. Our measurements show that the apparent eastward velocity varies from 200 m/s to 150 m/s at 2000 LT, and then it decreases to 100–50 m/s at midnight. On a magnetically disturbed day, reversal of the zonal apparent drift was observed just after midnight, and the apparent westward velocities observed at early in the morning showed large variations with location in the sky. From the receivers spaced in the geomagnetic north–south direction we measured near-zero time shifts, from which we conclude that the correlation length of several-hundred-meter-scale irregularities is much larger than 70-m separation between the north and south receivers.