Long-term trends in foF2 over Moscow ionosonde station: Its estimate and origins

	Long-term trends in foF2 over Moscow ionosonde station: Its estimate and origins
	Fang HanXian; Weng LiBin; Yang ShengGao; Wang SiCheng
刊名	CHINESE SCIENCE BULLETIN
	2012
卷号	57 期号:12 页码:1443-1448
关键词	ionosphere long-term trends IRI-2007 Moscow
ISSN号	1001-6538
通讯作者	Weng, LB (reprint author), Peoples Liberat Army Univ Sci & Technol, Inst Meteorol, Nanjing 211101, Jiangsu, Peoples R China.
中文摘要	We introduce a new approach, using the International Reference Ionosphere 2007 (IRI-2007) model and observations from the Moscow ionosonde station, to analyze the long-term trends of ionospheric foF2. Possible origins, whether natural or manmade, are discussed. A small but significant residual foF2 trend is found, with -0.76 MHz over the past 50 years, but -0.2 MHz after eliminating the most variations caused by solar and geomagnetic activities and the variational earth's magnetic field. We find that this slope depends on local time and seasons. There is a pronounced diurnal negative variation in k (annual mean slope of diurnal variations), with much larger absolute values in the morning than during afternoon or evening; the largest k is about -0.0018 per year in spring, and the smallest trend of about -0.0012 per year occurs in winter. Finally, the evidence of crucial influences of geomagnetic activity and the earth's magnetic field on the observed trends, as emphasized by the IRI-2007 empirical model, is confirmed, and the effect of CO2 contributions to the trend is also discussed, by cooling the thermospheric temperature or recombining the electron density.
英文摘要	We introduce a new approach, using the International Reference Ionosphere 2007 (IRI-2007) model and observations from the Moscow ionosonde station, to analyze the long-term trends of ionospheric foF2. Possible origins, whether natural or manmade, are discussed. A small but significant residual foF2 trend is found, with -0.76 MHz over the past 50 years, but -0.2 MHz after eliminating the most variations caused by solar and geomagnetic activities and the variational earth's magnetic field. We find that this slope depends on local time and seasons. There is a pronounced diurnal negative variation in k (annual mean slope of diurnal variations), with much larger absolute values in the morning than during afternoon or evening; the largest k is about -0.0018 per year in spring, and the smallest trend of about -0.0012 per year occurs in winter. Finally, the evidence of crucial influences of geomagnetic activity and the earth's magnetic field on the observed trends, as emphasized by the IRI-2007 empirical model, is confirmed, and the effect of CO2 contributions to the trend is also discussed, by cooling the thermospheric temperature or recombining the electron density.
学科主题	空间物理
收录类别	SCI
资助信息	National Natural Science Foundation of China [40890162, 40505005]; Specialized Research Fund for State Key Laboratories
语种	英语
公开日期	2014-12-15
内容类型	期刊论文
源URL	[http://ir.nssc.ac.cn/handle/122/3301]
专题	国家空间科学中心_空间科学部
推荐引用方式 GB/T 7714	Fang HanXian,Weng LiBin,Yang ShengGao,et al. Long-term trends in foF2 over Moscow ionosonde station: Its estimate and origins[J]. CHINESE SCIENCE BULLETIN,2012,57(12):1443-1448.
APA	Fang HanXian,Weng LiBin,Yang ShengGao,&Wang SiCheng.(2012).Long-term trends in foF2 over Moscow ionosonde station: Its estimate and origins.CHINESE SCIENCE BULLETIN,57(12),1443-1448.
MLA	Fang HanXian,et al."Long-term trends in foF2 over Moscow ionosonde station: Its estimate and origins".CHINESE SCIENCE BULLETIN 57.12(2012):1443-1448.