This study is a contribution to the estimation of the winter anomaly in the F2 layer of the ionosphere at low latitudes. The aim is to study the variability of the virtual height (hmF2) of the F2 region of the ionosph...This study is a contribution to the estimation of the winter anomaly in the F2 layer of the ionosphere at low latitudes. The aim is to study the variability of the virtual height (hmF2) of the F2 region of the ionosphere through the predictions of the latest International Reference Ionosphere model (IRI-2016). The present work allows analyzing the temporal evolution of hmF2 according to the different phases of three (3) solar cycles during the quiet geomagnetic activity to estimate the seasonal anomaly at the Ouagadougou station. The analysis of the seasonal profiles shows that the variability of hmF2 is: 1) strongly linked to the solar cycle activity, 2) dependent on the season and 3) variable from one cycle to the next for the same phase. It appears that hmF2 increases during the ascending phase to reach its maximum value at the phase maximum. During the descending phase, it decreases until the phase minimum where it finds its minimum value. The difference between winter and summer on the hmF2 values for each phase of the cycle is obtained at the phase minimum and is estimated to be at least 16 km. In low latitudes, solar irradiation is greater in summer than in winter. From this study, hmF2 values are larger in winter compared to summer indicating an anomaly in the virtual height of the F2 layer of the ionosphere through the predictions of IRI-2016 at the Ouagadougou station.展开更多
针对电离层对无线电传播带来的影响,该文利用2005—2015年拉萨站GPS双频接收机观测到的电离层垂直总电子含量(vertical total electron content,VTEC)数据,研究了拉萨地区的电离层变化的特性。实验分析结果表明:拉萨地区的电离层VTEC值...针对电离层对无线电传播带来的影响,该文利用2005—2015年拉萨站GPS双频接收机观测到的电离层垂直总电子含量(vertical total electron content,VTEC)数据,研究了拉萨地区的电离层变化的特性。实验分析结果表明:拉萨地区的电离层VTEC值分别有明显的半年周期和年周期变化。在2011年和2014年出现“冬季异常”现象。此外,拉萨地区垂直电离层VTEC与太阳活动指数F 10.7之间的为强相关性,两者之间的相关性系数达到0.99。展开更多
Temporal and spatial variation of ionosphere can influence our daily communication activities. By solving the one-year global positioning system （GPS） data of Shandong Continuous Operational Reference System （SDCOR...Temporal and spatial variation of ionosphere can influence our daily communication activities. By solving the one-year global positioning system （GPS） data of Shandong Continuous Operational Reference System （SDCORS） in 2012, we modeled the single-layer spherical harmonic model of vertical total electron content （TEC） over Shandong Province, China, and analyzed the time series of TEC in 2012. The ionosphere over Shandong in 2012 was in the peak year of solar activity. The ionospheric model over Shandong was calibrated and verified using data of the Center for Orbit Determination in Europe （CODE） and the Crustal Movement Observation Network of China （CMONOC）, respectively. The ionosphere is greatly influenced by latitude and solar activity and has the phenomenon of Winter anomaly and semiannual anomaly as well as the session change, diurnal variation, monthly change and seasonal variations. So we can grasp the regularity of temporal and spatial distribution of ionosphere over Shandong, China.展开更多
文摘This study is a contribution to the estimation of the winter anomaly in the F2 layer of the ionosphere at low latitudes. The aim is to study the variability of the virtual height (hmF2) of the F2 region of the ionosphere through the predictions of the latest International Reference Ionosphere model (IRI-2016). The present work allows analyzing the temporal evolution of hmF2 according to the different phases of three (3) solar cycles during the quiet geomagnetic activity to estimate the seasonal anomaly at the Ouagadougou station. The analysis of the seasonal profiles shows that the variability of hmF2 is: 1) strongly linked to the solar cycle activity, 2) dependent on the season and 3) variable from one cycle to the next for the same phase. It appears that hmF2 increases during the ascending phase to reach its maximum value at the phase maximum. During the descending phase, it decreases until the phase minimum where it finds its minimum value. The difference between winter and summer on the hmF2 values for each phase of the cycle is obtained at the phase minimum and is estimated to be at least 16 km. In low latitudes, solar irradiation is greater in summer than in winter. From this study, hmF2 values are larger in winter compared to summer indicating an anomaly in the virtual height of the F2 layer of the ionosphere through the predictions of IRI-2016 at the Ouagadougou station.
文摘针对电离层对无线电传播带来的影响,该文利用2005—2015年拉萨站GPS双频接收机观测到的电离层垂直总电子含量(vertical total electron content,VTEC)数据,研究了拉萨地区的电离层变化的特性。实验分析结果表明:拉萨地区的电离层VTEC值分别有明显的半年周期和年周期变化。在2011年和2014年出现“冬季异常”现象。此外,拉萨地区垂直电离层VTEC与太阳活动指数F 10.7之间的为强相关性,两者之间的相关性系数达到0.99。
基金supported by the National Natural Science Foundation of China(No.41374009)the National Basic Science and Technology Special Project of China(No. 2015FY310200)+1 种基金the Shandong Natural Science Foundation of China (No.ZR2013DM009)the SDUST Research Fund(No. 2014TDJH101)
文摘Temporal and spatial variation of ionosphere can influence our daily communication activities. By solving the one-year global positioning system （GPS） data of Shandong Continuous Operational Reference System （SDCORS） in 2012, we modeled the single-layer spherical harmonic model of vertical total electron content （TEC） over Shandong Province, China, and analyzed the time series of TEC in 2012. The ionosphere over Shandong in 2012 was in the peak year of solar activity. The ionospheric model over Shandong was calibrated and verified using data of the Center for Orbit Determination in Europe （CODE） and the Crustal Movement Observation Network of China （CMONOC）, respectively. The ionosphere is greatly influenced by latitude and solar activity and has the phenomenon of Winter anomaly and semiannual anomaly as well as the session change, diurnal variation, monthly change and seasonal variations. So we can grasp the regularity of temporal and spatial distribution of ionosphere over Shandong, China.
