The application of GPS observations to equatorial aeronomy
The application of GPS observations to equatorial aeronomy
复制标题
DOI：
10.1029/1999rs002208
复制
发表时间：
2000-05
期刊：
影响因子：
1.6
通讯作者：
M. Mendillo;B. Lin;J. Aarons
中科院分区：
文献类型：
--
作者：
M. Mendillo;B. Lin;J. Aarons
电离层对全球定位系统卫星信号的传播影响的常规观测可从国际全球定位系统地球动力学服务处在线获得。目前有200多个地面站报告数据，电离层研究从单点观测分析到整个全球网络，都证明了这一非凡资源可能产生的地球物理产量。在这篇文章中，我们扩展了利用GPS数据在低纬地区进行全面的“区域研究”。利用南美洲的GPS观测点，我们展示了如何处理常规观测以形成可靠的总电子含量(TEC)值，该值能够描述整个大陆上的纬度、经度、当地时间和风暴时间行为。为了研究低纬地区占主导地位的F区结构--阿普尔顿异常，发展了两个指数来评估其强度(IS)和不对称性(Ia)。利用30个S间隔的TEC数据，形成了捕获15min(Fp)和小时(Fp)时间分辨率的等离子体不规则性的相位起伏指数。在大西洋和太平洋扇区位置的FP测试表明，它们可以准确地再现赤道扩散F(ESF)的所有已知发生模式。使用三个指数(IS、Ia和Fp)根据增长速度指标的增强或抑制来制定ESF的预测能力并不是特别成功。
Routine observations of the ionospherically imposed propagation effects upon GPS satellite signals are available online from the International GPS Service for Geodynamics. With over 200 ground‐based stations now reporting data, ionospheric studies ranging from the analysis of single‐site observations to the full global network have demonstrated the geophysical science yield possible from this remarkable resource. In this paper we expand on the use of GPS data for comprehensive “regional studies” at low latitudes. Using the GPS observing sites in South America, we show how routine observations are processed to form reliable total electron content (TEC) values capable of describing the latitudinal, longitudinal, local time, and storm time behavior over the full span of the continent. To study the dominant F region structure at low latitudes, the Appleton anomaly, two indices are developed to assess its strength (Is) and asymmetry (Ia). TEC data at 30 s intervals are used to form phase fluctuation indices that capture plasma irregularity patterns at 15‐min (fp) and hourly (Fp) time resolution. Tests of Fp at Atlantic and Pacific sector locations show them to reproduce accurately all known occurrence patterns for equatorial spread F (ESF). The use of the three indices (Is,Ia, and Fp) to formulate predictive capabilities for ESF on the basis of the enhancement or suppression of growth rate indicators was not particularly successful.