Sulungu Emmanuel D
Department of Physics, The University of Dodoma, Dodoma, Tanzania.
Sci Rep. 2024 May 1;14(1):10010. doi: 10.1038/s41598-024-59624-0.
This study evaluated the applicability of IRI-2016 model in predicting GPS TEC using the monthly means of the five (5) quiet days for equinoxes and solstices months. GPS-derived TEC data were obtained from the IGS network of ground based dual frequency GPS receivers from three stations [(KYN3 0.53° S, 38.53° E; Geom. Lat. 3.91.63° S), (MBAR 0.60° S, 30.74° E; Geom. Lat. 2.76° S) and HOID 1.45° S, 31.34° E; Geom. Lat. 3.71° S]. All the three options for topside Ne of IRI-2016 model and ABT-2009 for bottomside thickness have been used to compute the IRI TEC. The results were compared with the GPS TEC measurements. Correlation Coefficients between the two sets of data, the Root-Mean Square Errors of the IRI-TEC from the GPS-TEC, and the percentage RMSE of the IRI-TEC from the GPS-TEC have been computed. In general, the IRI-2016 model underestimated GPS-TEC during the nighttime, whereas the model overestimated GPS-TEC values during the daytime. At most of the stations and during all seasons where data were available, correlation coefficient was above 0.9, which is quite strong. The variation of O/N2 ratio may potentially be the cause of the IRI TEC deviation from the GPS TEC. This variation arises from lower thermosphere plasma drift that moves upward.
本研究利用二分点和二至点月份五个安静日的月均值，评估了IRI - 2016模型在预测全球定位系统总电子含量（GPS TEC）方面的适用性。GPS导出的TEC数据来自三个站点的国际GNSS服务（IGS）地面双频GPS接收机网络[（KYN3，南纬0.53°，东经38.53°；地磁纬度南纬3.91.63°），（MBAR，南纬0.60°，东经30.74°；地磁纬度南纬2.76°）和HOID，南纬1.45°，东经31.34°；地磁纬度南纬3.71°]。IRI - 2016模型的三种顶部电离层电子密度（Ne）选项以及ABT - 2009底部电离层厚度选项均用于计算IRI TEC。将结果与GPS TEC测量值进行比较。计算了两组数据之间的相关系数、IRI - TEC相对于GPS - TEC的均方根误差以及IRI - TEC相对于GPS - TEC的均方根误差百分比。总体而言，IRI - 2016模型在夜间低估了GPS - TEC，而在白天高估了GPS - TEC值。在大多数站点以及所有有数据的季节，相关系数均高于0.9，相关性很强。O/N2比值的变化可能是IRI TEC与GPS TEC出现偏差的原因。这种变化源于向上移动的低热层等离子体漂移。
