IRI-2007预测TEC在广州地区的适用性分析

利用广州站(23.2°N, 113.3°E) GPS双频接收机监测的电离层TEC数据和IRI-2007模型不同电离层输入参数计算得到的TEC预测值, 对比分析了太阳活动低年(2008年)广州地区TEC的变化特征. 结果表明, TEC观测值周日变化在16:00LT左右达到最大值, 而IRI-TEC最大值出现时间较GPS-TEC提前1h左右. TEC季节变化在春秋分较高, 两至季节较低, 表现出明显的半年特性和季节依赖性, 并出现冬季异常现象. IRI-TEC与GPS-TEC在白天具有较好的一致性, 夜间偏差较大. 不同电离层输入参数得到的TEC预测值也相差较大, 选用顶部电子密度参数NeQuick、底部厚度参数B0 Table并用URSI系数计算F₂层峰值参数时, 能较好地反映TEC观测值的变化特征. 在对磁暴的响应上, 预测值无明显变化, 观测值则有比较明显的表现. 通过对比, 初步分析了利用IRI-2007模型预测TEC在广州地区的适用性, 并给出了合理的参数选择方案. 

Applicability Analysis of IRI-2007 in Predicting TEC Over Guangzhou Region

By using GPS-TEC data observed in 2008 and IRI-TEC data derived from IRI-2007 model, the variations of Total Electron Content (TEC) are studied over Guangzhou (23.2°N, 113.3°E), which is in the equatorial anomaly region. Results show that the diurnal variation of GPS-TEC shows a peak value at about 16:00LT, while IRI-TEC is at about 15:00LT. The seasonal variation of TEC appears a winter anomaly and semiannual pattern, maxima in equinoxes and minima in summer and winter. A good agreement is found between IRI-TEC and GPS-TEC in daytime, but a bit large deviation in nighttime, and the IRI-TEC is in more agreement with the GPS-TEC when choosing NeQuick, B0 Table and URSI parameters. However, GPS-TEC shows apparent response to magnetic storm while IRI-TEC does not show any response to it. Through comparison, the applicability of IRI-2007 model in predicting TEC is analyzed over Guangzhou region, and the reasonable input options of parameters are also discussed.