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Solar activity effects of the ionosphere: A brief review

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Chinese Science Bulletin 2011年第12期56卷 1202-1211页

作者： LIU LiBo WAN WeiXing CHEN YiDing le huijun Institute of Geology and Geophysics Chinese Academy of Sciences Beijing 100029 China State Key Laboratory of Space Weather Center for Space Science andApplied Research Chinese Academy of Sciences Beijing 100190 China

Solar radiation, which varies over multiple temporal scales, modulates remarkably the evolution of the ionosphere. The solar activity dependence of the ionosphere is a key and fundamental issue in ionospheric physics, providing information essential to understanding the variations in the ionosphere and its processes. Selected recent studies on solar activity effects of the ionosphere are briefly reviewed in this report. This report focuses on (1) observations of solar irradiance at X-ray and extreme ultraviolet wavelengths and the outstanding problems of solar proxies, in the view of ionospheric studies, (2) new findings and improved representations of the features of the solar activity dependence of ionospheric key parameters and the corresponding physical processes, (3) possible phenomena in the ionosphere under extremely high and low solar activity conditions that are unique, as indicated by historical solar datasets and the deep solar minimum of solar cycle 23/24, and (4) statistical studies and model simulations of the ionosphere response to solar flares. The above-mentioned studies provide new clues for comprehensively explaining basic processes in the ionosphere and improving the prediction capability of ionospheric models and related applications.

关键词：太阳活动周期电离层物理电离层模型太阳能太阳辐射时间尺度辐射观测物理过程

Anomaly distribution of ionospheric total electron content responses to some solar flares

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Earth and Planetary Physics 2019年第6期3卷 481-488页

作者： huijun le LiBo Liu YiDing Chen Hui Zhang Key Laboratory of Earth and Planetary Physics Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China Innovation Academy of Earth Science Chinese Academy of SciencesBeijing 100029China Beijing National Observatory of Space Environment Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China College of Earth and Planetary Sciences University of the Chinese Academy of SciencesBeijing 100049China

Previous studies have shown that the ionospheric responses to a solar flare are significantly dependent on the solar zenith angle(SZA):the ionospheric responses are negatively related to the *** largest enhancement in electron density always occurs around the subsolar ***,from 2001 to 2014,the global distribution of total electron content(TEC)responses showed no obvious relationship between the increases in TEC and the SZA during some solar *** these solar flares,the greatest enhancements in TEC did not appear around the subsolar point,but rather far away from the subsolar *** distribution of TEC enhancements showed larger TEC enhancements along the same *** distribution of anomalous ionospheric responses to the solar flares was not structured the same as traveling ionospheric *** anomaly distribution was also unrelated to the distribution of background neutral *** could not be explained by changes in the photochemical process induced by the solar ***,the transport process could be one of the main reasons for the anomaly distribution of ionospheric responses to the solar *** anomaly distribution also suggests that not only the photochemical process but also the transport process could significantly affect the variation in ionospheric electron density during some solar flares.

关键词： solar flare ionospheric response transport process

A brief review of equatorial ionization anomaly and ionospheric irregularities

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Earth and Planetary Physics 2018年第4期2卷 257-275页

作者： Nanan Balan LiBo Liu huijun le Key Laboratory of Earth and Planetary Physics Institute of Geology and Geophysics Chinese Academy of Sciences Institutions of Earth Science Chinese Academy of Sciences College of Earth and Planetary Sciences University of the Chinese Academy of Sciences

Following a brief history and progress of ionospheric research, this paper presents a brief review of the recent developments in the understanding of two major phenomena in low and mid latitude ionosphere—the equatorial ionization anomaly(EIA) and involved equatorial plasma fountain(EPF) and ionospheric irregularities. Unlike the easy-to-understand misinterpretations, the EPF involves field perpendicular E×B plasma drift and field-aligned plasma diffusion acting together and plasma flowing in the direction of the resultant at all points along the field lines at all altitudes. The EIA is formed mainly from the removal of plasma from around the equator by the upward E×B drift creating the trough and consequently the crests with small accumulation of plasma at the crests when the crests are within ~±20° magnetic latitudes and no accumulation when they are beyond ~±25° magnetic latitudes. The strong EIA under magnetically active conditions arises from the simultaneous impulsive action of eastward prompt penetration electric field and equatorward neutral wind. Intense ionospheric irregularities develop in the post-sunset bottom-side equatorial ionosphere when it rises to high altitudes, and evolve nonlinearly into the topside. Pre-reversal enhancement(PRE) of the vertical upward E×B drift and its fluctuations amplified during PRE provide the driving force and seed, with neutral wind and gravity waves being the primary sources. At low solar activity especially in summer when fast varying PRE is absent, the slow varying gravity waves including large scale waves(LSW)seem to act as both driver and seed for weak irregularities. At mid latitudes, the irregularities are weak and associated with medium scale traveling ionospheric disturbances(MSTIDs). A low latitude minimum in the occurrence of the irregularities at March equinox predicted by theoretical models is identified. The minimum occurs on the poleward side of the EIA crest and shifts equatorward from ~25° magnetic latit

关键词： equatorial ionization anomaly ionospheric irregularities

Development of a middle and low latitude theoretical ionospheric model and an observation system data assimilation experiment

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Chinese Science Bulletin 2008年第1期53卷 94-101页

作者： YUE XinAn WAN WeiXing LIU LiBo le huijun CHEN YiDing YU Tao Institute of Geology and Geophysics Chinese Academy of Sciences Beijing 100029 China Wuhan Institute of Physics and Mathematics Chinese Academy of Sciences Wuhan 430071 China Graduate University of Chinese Academy of Sciences Beijing 100049 China National Center for Spaceweather CMA Beijing 100081 China

On the basis of previous work, we develop a middle and low latitude theoretical ionospheric model in this paper, named Theoretical Ionospheric Model of the Earth in the Institute of Geology and Geophysics, Chinese Academy of Sciences (TIME-IGGCAS). TIME-IGGCAS solves the equations of mass continuity, motion and energy of electron and ions self-consistently and uses an eccentric dipole field approxima-tion to the Earth’s magnetic field. We combine the Eulerian and Lagrangian approaches in the model and take account of the plasma E×B drift velocity. Calculation results reveal that the model is steady and credible and can reproduce most large-scale features of ionosphere. By using TIME-IGGCAS, we carried out an observation system data assimilation experiment. Assimilation results show that the E×B drift velocity can be accurately estimated by ingesting the observed foF2 and hmF2 into the model ap-plying nonlinear least-square fit method. We suggest that this work is of great significance in the de-velopment of ionospheric data assimilation model to give better nowcast and forecast of ionosphere.

关键词：电离层理论模型数据同化纬度

Recent Progresses on Ionospheric Climatology Investigations

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空间科学学报 2012年第5期32卷 665-680页

作者： LIU Libo WAN Weixing CHEN Yiding le huijun ZHAO Biqiang (Beijing National Observatory of Space Environment Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029

The ionosphere varies over multiple time scales,which are classified into two categories: the climatology and weather *** this national report,we give a brief summary of recent progresses in ionospheric climatology with focus on(1) the seasonal variations,(2) solar cycle effects, and(3) empirical modeling of the *** seasonal variations of the ionosphere have been explored in many works to give a more detailed picture with regional and global features at various altitudes by analyzing the observation data from various sources and ***,a series of studies reported the response of the ionosphere to solar cycle variations,which revealed some novel and detailed features of solar activity dependence of ionospheric parameters at different altitudes. These investigations have improved our understanding on the states of the ionosphere and underlying fundamental processes,provided clues to future studies on ionospheric weather,and guided ionospheric modeling,forecasting and related applications.

关键词： Ionosphere Climatological variation Seasonal variations Solar cycle Ionospheric modeling

Some Investigations on the Ionosphere during 2012–2014 in China

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空间科学学报 2014年第5期34卷 648-668页

作者： LIU Libo CHEN Yiding le huijun LIU Jing WAN Weixing Key Laboratory of Earth and Planetary Physics Institute of Geology and GeophysicsChinese Academy of Sciences Beijing National Observatory of Space Environment Institute of Geology and GeophysicsChinese Academy of Sciences

In this national biannual report, we will outline some recent progresses in ionospheric studies conducted by Chinese scientists since 2012. The mentioned aspects include: the solar activity control of the ionosphere; couplings between the ionosphere, lower atmosphere and plasmasphere;ionospheric climatology and disturbances; ionospheric irregularities and scintillation; models, data assimilation and simulations; unusual phenomena of the ionosphere; possible seismic signatures presented in ionospheric observations, and some methodology progresses. These progresses will enhance our ability to observe the ionosphere, provide more reasonable understanding about the states of the ionosphere and underlying fundamental processes, and stimulate ionospheric modeling, forecasting and related applications.

关键词： Ionospheric weather Ionospheric climatology Ionospheric storm Waves

Measurement of Martian atmospheric winds by the O_(2) 1.27 μm airglow observations using Doppler Michelson Interferometry: A concept study

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Science China Earth Sciences 2021年第11期64卷 2027-2042页

作者： Na YANG Chunliang XIA Tao YU Xiaomin ZUO Yangyi SUN Xiangxiang YAN Jian ZHANG Jin WANG huijun le Libo LIU William Edmund WARD Hubei Subsurface Multi-scale Imaging Key Laboratory Institute of Geophysics and GeomaticsChina University of GeosciencesWuhan 430074China Key Laboratory of Earth and Planetary Physics Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China Institutions of Earth Science Chinese Academy of SciencesBeijing 100029China Mohe Observatory of Geophysics Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China University of the Chinese Academy of Sciences Beijing 100049China Department of Physics University of New BrunswickNew BrunswickFredericton E3B 5A3Canada

China’s Mars exploration mission has stimulated tremendous interest in planetary science exploration *** propose potential scientific research projects,this study presents a concept simulation for the measurement of Martian atmospheric winds using the Doppler Michelson interferometry *** simulation is based on the satellite instrument initially designed for the Dynamic Atmosphere Mars Observer(DYNAMO)project to measure vertical profiles of winds from the 1.27μm airglow observations in the Martian atmosphere.A comprehensive DYNAMO measurement simulation forward model based on an orbit submodel,an atmospheric background field submodel,and an instrument submodel is developed using the Michelson *** simulated interferogram signal over the field of view(FOV)calculated by the forward model is associated with the filter transmittance function,column emission rate of airglow,wind velocity,temperature,and the Michelson *** agreement between the derived atmospheric signals from the simulated interferogram without altitude inversion and the input parameters used to initiate the forward model confirms the validity of the forward model.

关键词： Martian atmospheric wind Doppler Michelson interferometer 1.27μm airglow

An analysis of thermospheric density response to solar flares during 2001-2006

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An analysis of thermospheric density response to solar flare...

Statistical analysis of ionospheric mid-latitude trough over the Northern Hemisphere derived from GPS total electron content data

中国科学院地质与地球物理研究所2012年度（第12届）学术年会

作者： huijun le Libo Liu Weixing Wan Beijing National Observatory of Space Environment Institute of Geology and GeophysicsChinese Academy of Sciences State Key Laboratory of Space Weather Center for Space Science and Applied ResearchChinese Academy of Sciences

[1]Previous studies show there are significant thermospheric responses to the two great solar flares on October 28,2003(X17.2) and November 4,2003(X28).In the present study,we further explored the thermospheric response to all X-class solar flares during *** observed results show that X5 and stronger solar flares can induce an average enhancement of 10-13%in thermospheric density in latitude 50°S-50°N within

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Statistical analysis of ionospheric mid-latitude trough over...