第24太阳活动周武汉电离层VTEC变化特性分析

Analysis of ionospheric VTEC at Wuhan station during 24th Solar Cycle

利用2008-2015年(第24太阳活动周)中国地壳运动监测网络(CMONOC)武汉站(30.5°N,114.4°E)GPS双频接收机监测的垂直总电子含量(VTEC)数据,分析电离层VTEC变化特性,并讨论VTEC与太阳活动的相关性.结果表明,VTEC估值周日变化在14:00-16:00LT左右达到最大值;同时,电离层VTEC也表现出明显的逐日变化特性,特别是在VTEC峰值处呈现较大差异.在太阳活动高年(2011-2015),VTEC变化呈现明显的双峰结构,即所谓的"半年异常"现象,春季峰值大于秋季峰值,"冬季异常"也更为明显.在各个季节(除春季外),VTEC与F_(10.7p)的相关性最好,与F_(10.7)的相关性次之,与太阳黑子数(SSN)的相关性稍弱;秋季VTEC与太阳活动的相关性最好(Max_(F10.7p)=0.92232,Max_(SSN)=0.85575),冬季VTEC与太阳活动的相关性最差(Min_(F10.7p)=0.79028,Min_(SSN)=0.72703).

By using the GPS-VTEC data observed at Wuhan station(30.5 N,114.4 E)of Crustal Movement Observation Network of China(CMONOC)from 2008 to 2015,the variations of ionospheric Vertical Total Electron Content(VTEC)are analyzed,and the VTEC correlation with solar activities are discussed.Results show that the diurnal variations of GPS-VTEC show a peak value at about 14:00-16:00 LT;meanwhile,VTEC shows day-today variability of ionospheric characteristics,a large difference exists especially in the VTEC peak.During high solar activity years(2011-2015),VTEC presents double-peak structure,that is,the so-called Semiannual anomaly,the Spring peak value is greater than the Autumn peak,and Winter anomaly is also more obvious during this period.Among all seasons(except for the Spring),the variation of GPS-VTEC correlated best with the F10.7p,followed by the F10.7,and then the SSN.The correlation between the daytime VTEC and the solar activity is superior to the correlation between the night-time VTEC and the solar activity.The correlation between VTEC and the solar activity is the best in Autumn(MaxF10.7p=0.92232,MaxSSN=0.85575),while the worst in Winter(MinF10.7p=0.79028,MinSSN=0.72703).