基于非相干散射雷达和GPS观测研究Millstone Hill地区等离子体层电子含量  

An investigation on plasmaspheric electron content derived from ISR and GPS observations at Millstone Hill

作　　者：种小燕[1,2,3] 张满莲[1,2] 张顺荣 温晋[1,2,3] 刘立波[1,2] 宁百齐[1,2] 万卫星[1,2] 

机构地区：[1]中国科学院地质与地球物理研究所,电离层空间环境重点实验室,北京100029 [2]中国科学院地质与地球物理研究所,北京空间环境国家野外科学观测研究站,北京100029 [3]中国科学院大学,北京100049 [4]Haystack Observatory,Massachusetts Institute of Technology

出　　处：《地球物理学报》2013年第3期738-745,共8页Chinese Journal of Geophysics

基　　金：院重点部署项目(KZZD-EW-01-3);国家自然科学基金(NSFC 41274163;40890164);国家重点基础研究发展计划(973计划)(2012CB825604);国家自然科学基金(NSFC 41131066;40974090)资助

摘　　要：本文尝试结合非相干散射雷达和GPS TEC观测数据提取等离子体层总电子含量(PTEC).我们首先描述所用的技术方法,然后具体利用了Millstone Hill台站的观测数据研究该地区上空等离子体层总电子含量(PTEC)的变化情况.我们采用变化标高的Chapman函数对非相干散射雷达测得的电子浓度剖面数据进行拟合,然后通过对剖面积分得到100km到1000km高度范围的电离层总电子含量.GPS提供的TEC数据为高度达20200km的总电子含量,两者之差可近似看成等离子体层的电子含量.本文分别选取太阳活动高年(2000,2002年)和太阳活动低年(2005,2008年)Millstone Hill台站的静日数据进行研究.结果表明,等离子体层电子含量及其所占GPSTEC的比例具有明显的周日变化.PTEC含量在白天高于夜间,而所占GPS TEC的百分比,夜间明显高于白天.太阳活动高年所选月份等离子体层电子含量在4～14TECU(1TECU=1016el/m2)范围内变化,夜间所占比例可达60%左右.太阳活动低年所选月份等离子体层电子含量在3～7TECU范围内变化,所占比例夜间最高可达80%左右.我们所得到的结果与前人基于其它观测手段所得结果在变化趋势上一致,在量级上也大致相当.因此,这从一个侧面证明了我们所用方法的可靠性.非相干散射雷达能够探测包括F2层峰值以下及以上高度的电子浓度,利用这一设备所观测得到的资料来推算电离层电子含量将比前人基于电离层垂测仪观测资料进行的推算更具真实性,由此得到的等离子体层电子含量也将更为接近真实情况.An attempt is made to estimate the plasmaspheric electron content （PTEC） using the data observed from the ISR （Incoherent Scatter Radar） and GPS at Millstone Hi11（42.6°N, 288.5°E）. We first present a brief description on the method we used in this study, then the variation of PTEC is studied. The electron density profile obtained by the ISR at Millstone Hill is fitted using Chapman function with varying scale heights, and then the ISR TEC is calculated as an integral of electron density from 100km to 1000km of the profile. The difference between GPS TEC （which is up to an altitude of 20200 km） and ISR TEC can be taken approximately as the plasmaspheric electron content （PTEC）. Data from both high solar activity years （2000 and 2002） and low solar activity years （2005 and 2008） are used for the present study. The results we obtained indicate that both PTEC and the relative contribution of PTEC （to GPSTEC） exhibit obvious diurnal variation patterns, with PTEC being higher during daytime than during nighttime and the relative contribution of PTEC is higher during nighttime than during daytime. PTEC can vary from 4 to 14 TECU （1TECU= 1016 el/m2） and the contribution of PTEC to GPS TEC reaches 60% during nighttime in the month of high solar activity level, while in the month of low solar activity, the value of PTEC is generally 3 ~ 7 TECU with the highest contribution about 80% at night. The variation pattern and trends in our results are in agreement with those obtained by other researches based on different measurements and techniques, and the magnitude is also agreed. This provides a support to the validity of our method. Unlike the ionosonde/digisonde which can only explore the bottomside ionosphere under the F2 peak, the ISR has the advantage to explore from a low to high altitude range and thus can provide both the bottomside and topside electron density profile. For this reason, the PTEC derived from ISR data （combined with GPS TEC） is more realistic than that from iono

关 键 词：TEC 等离子体层 非相干散射雷达 GPSTEC 电离层 

分 类 号：P352[天文地球—空间物理学]