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Recent ionospheric investigations in China(2018–2019)

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Earth and Planetary Physics 2020年第3期4卷 179-205页

作者： LiBo Liu weixing wan Key Laboratory of Earth and Planetary Physics Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China Innovation Academy for Earth Science Chinese Academy of SciencesBeijing 100029China Beijing National Observatory of Space Environment Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100101China College of Earth and Planetary Sciences University of the Chinese Academy of SciencesBeijing 100019China

Since the release of the 2018 National Report of China on ionospheric research(Liu LB and wan WX,2018)to the Committee on Space Research(COSPAR),scientists from China's Mainland have made many new fruitful investigations of various ionospheric-related *** this update report,we briefly introduce more than 130 recent reports(2018–2019).The current report covers the following topics:ionospheric space weather,ionospheric structures and climatology,ionospheric dynamics and couplings,ionospheric irregularity and scintillation,modeling and data assimilation,and radio wave propagation in the ionosphere and sounding techniques.

关键词： ionosphere ionospheric storm ionospheric climatology ionospheric irregularity GNSS space weather

Equatorial aurora: the aurora-like airglow in the negative magnetic anomaly

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National Science Review 2020年第10期7卷 1606-1615页

作者： Fei He Yong Wei weixing wan Key Laboratory of Earth and Planetary Physics Institute of Geology and Geophysics Chinese Academy of Sciences College of Earth and Planetary Sciences University of Chinese Academy of Sciences

The most fantastic optical phenomena in the Earth’s upper atmosphere are the auroras. They are highly informative indicators of solar activity, geomagnetic activity, upper atmospheric structures and dynamics,and magnetospheric energetic particles. An area where the geomagnetic field differs significantly from the expected symmetric dipole, such as at the South Atlantic Anomaly, where the magnetic field intensity is low,gives rise to stronger precipitation of energetic particles into the upper atmosphere. Impact excitation and the subsequent airglow emissions exhibit aurora-like dynamic signatures. Nomenclatures of nonpolar aurora or equatorial auroras are similar to those used with the polar auroras owing to their similar excitation mechanisms. This paper provides an overview of the knowledge and the challenges concerning auroral activity at the South Atlantic Anomaly, or more generally, at the negative magnetic anomaly. We emphasize systematic investigation of the equatorial auroras to reveal the temporal and spatial evolution of the magnetic anomaly and the behaviour of energetic particles in near-Earth space.

关键词： aurora geomagnetic field South Atlantic Anomaly negative magnetic anomaly energetic particles

Stagnant low-energy ions in the near cusp region observed by Cluster

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Science China Earth Sciences 2017年第7期60卷 1299-1309页

作者： LI Kun WEI Yong wan weixing Key Laboratory of Earth and Planetary Physics Institute of Geology and Geophysics Chinese Academy of Sciences Lunar and Planetary Science Laboratory Macao University of Science and Technology-Partner Laboratory of Key Laboratory of Lunar and Deep Space Exploration Chinese Academy of Sciences College of Earth Sciences University of Chinese Academy of Sciences

Measuring the low-energy ions in the Earth's magnetotail lobes is difficult, because a spacecraft becomes positively charged in a sunlit and tenuous plasma environment. Recent studies have introduced a new method, making use of the positive electric potential on the Cluster spacecraft, to measure the low-energy ions(less than a few tens of electronvolts) in the polar caps/magnetotail lobes in the years 2001–2010. With the measured velocities, we are able to study the trajectories of these low-energy ions. Particle tracing has been used in previous studies, confirming that ions of ionospheric origin are the dominant contributor to the ion population in the Earth's magnetotail lobes. In this work, we continue to study the source of low-energy ions measured in the lobes. We found that not all of the low-energy ions in the lobes come directly from the ionosphere. Particle tracing infers that some of the low-energy ions start to move tailward from the cusp/near-cusp region with a zero parallel velocity. In the following, we refer to these low-energy ions as stagnant low-energy ions. On the other hand, the in situ measurements by Cluster show a population of low-energy ions in the cusp/near-cusp region with pitch angles near 90°(i.e., no significant parallel velocity).The locations of stagnant low-energy ions are determined by particle tracing and in situ measurements. Similar ion energies and spatial distributions determined by these two methods confirm the presence of the stagnant low-energy ion population.

关键词： Ionospheric outflow Low-energy ion Potential energy balance Ion stagnation

A Review on the Ionospheric Research:Chinese Works During 2006—2008

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空间科学学报 2008年第5期28卷 468-491页

作者： wan weixing Institute of Geology and Geophysics Chinese Academy of Sciences Beijing 100029

This paper reviews various progresses on the ionospheric studies by the scientists in China during the last two *** main contents concern the 4 aspects of the ionospheric re-search:(1) ionospheric weather and coupling with magnetosphere(polar and auroral ionosphere,ionospheric response to substorms,ionospheric storms);(2) mid-and low-latitude ionospheric clima-tology(ionospheric properties,yearly variations and solar activity dependence,long term variation);(3) ionospheric coupling with neutral atmosphere(gravity waves,tides,planetary waves,background upper atmosphere,and ionospheric response);and(4) ionospheric diagnostics(observation,modeling,and prediction).

关键词：中国地球空间研究研究进展气候

A Review of the Ionospheric Investigations in China:Progress During 2008-2010

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空间科学学报 2010年第4期30卷 362-381页

作者： wan weixing Beijing National Observatory of Space Environment Institute of Geology and Geophysics Chinese Academy of Sciences Beijing 100029 China

In the ionospheric research,various progresses have been made during the last two *** paper reviews the recent works of Chinese *** convenience,the contents include:ionospheric storms and space weather;ionospheric irregularities and scintillation;ionospheric variability;ionospheric disturbances;ionospheric response to solar eclipses;ionospheric coupling with atmosphere and lithosphere;ionospheric climatology;ionospheric modeling;and ionospheric prediction and application.

关键词：电离层暴中国科学家综述电离层扰动电离层耦合电离层预报电离层模型空间天气

Wavenumber-4 spectral component extracted from TIMED/SABER observations

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Earth and Planetary Physics 2020年第5期4卷 436-448页

作者： Xing Li weixing wan JinBin Cao ZhiPeng Ren Key Laboratory of Earth and Planetary Physics Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China School of Space and Environment Beihang UniversityBeijing 100083China Key Laboratory of Space Environment Monitoring and Information Processing Ministry of Industry and Information TechnologyBeijing 100083China Beijing National Observatory of Space Environment Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China Innovation Academy for Earth Science Chinese Academy of SciencesBeijing 100029China University of the Chinese Academy of Sciences Beijing 100049China

The wavenumber spectral components WN4 at the mesosphere and low thermosphere(MLT)altitudes(70–10 km)and in the latitude range between±45°are obtained from temperature data(T)observed by the Sounding of the Atmosphere using Broadband Emission Radiometry(SABER)instruments on board the National Aeronautics and Space Administration(NASA)’s Thermosphere–Ionosphere–Mesosphere Energetics and Dynamics(TIMED)spacecraft during the 11-year solar period from 2002 to *** analyze in detail these spectral components WNk and obtain the main properties of their vertical profiles and global *** report that all of the wavenumber spectral components WNk occur mainly around 100 km altitude,and that the most prominent component is the wavenumber spectral component WN4 *** these long duration temperature data with results of previous investigations,we have found that the yearly variation of spectral component WN4 is similar to that of the eastward propagating non-migrating diurnal tide with zonal wavenumber 3(DE3)at the low latitudes,and to that of the semi-diurnal tide with zonal wavenumber 2(SE2)at the mid-latitudes:the amplitudes of the A4 are larger during boreal summer and autumn at the low-latitudes;at the mid-latitudes the amplitudes have a weak peak in *** addition,the amplitudes of component WN4 undergo a remarkable short period variation:significant day-to-day variation of the spectral amplitudes A4 occurs primarily in July and September at the *** summary,we conclude that the non-migrating tides DE3 and SE2 are likely to be the origins,at the low-latitudes and the mid-latitudes in the MLT region,respectively,of the observed wavenumber spectral component WN4.

关键词： TIMED observations wavenumber spectral components non-migrating tides short period variation

The source of tropospheric tides

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Earth and Planetary Physics 2020年第5期4卷 449-460页

With the method of Hough mode decomposition(HMD),the tidal sources of the three main tidal components,namely,the migrating components DW1(diurnal westward propagating wavenumber 1)and SW2(semidiurnal westward propagating wavenumber 2)and the non-migrating component DE3(diurnal eastward propagating wavenumber 3),at the tropospheric altitudes(1–12 km)and in the latitude range of±60°,were obtained from National Centers for Environmental Prediction(NCEP)Climate Forecast System Reanalysis(CFSR)data during the interval from 1988 to *** analyzed these sources in detail at 6 km and obtained the main properties of their yearly *** DW1 source was found to present a weak seasonal variation in the lower latitudes(about±10°–15°).That is,the amplitudes of the DW1 sources were larger in the summer months than in the winter months,and DW1 presented semi-annual variation near the equator(±10°)such that the DW1 source was larger at the equinoxes than at the *** addition,the SW2 source was symmetric and was stronger in the southern hemisphere than in the northern *** SW2 source presented remarkable annual and semi-annual variation such that the amplitudes were largest during the March equinox months and larger during the June solstice *** contrast,DE3 appeared mainly around the equatorial latitudes within about±30°.The DE3 source presented remarkable semiannual variation that was larger around the solstices than the equinoxes in the southern hemisphere,and it was opposite in the northern *** HMD,we found that the tropospheric tides were primarily dominated by some leading propagating Hough modes,specifically,the(1,1),(2,3),and(3,3)modes;the influences of the other Hough modes were *** consequences of an El Niño–Southern Oscillation modulation of tidal amplitudes for the energy and momentum budgets of the troposphere may now be expected to attract *** summary,the above yearly variations of the main tidal sources and

关键词： tropospheric tides Hough mode decomposition yearly variations

Influence of annual atmospheric tide asymmetry on annual anomalies of the ionospheric mean state

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Earth and Planetary Physics 2020年第5期4卷 429-435页

作者： ZhiPeng Ren weixing wan JianGang Xiong Xing Li Key Laboratory of Earth and Planetary Physics Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China Innovation Academy for 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 School of Space and Environment Beihang UniversityBeijing 100083China Key Laboratory of Space Environment Monitoring and Information Processing Ministry of Industry and Information TechnologyBeijing 100083China

Through respectively adding June tide and December tide at the low boundary of the GCITEM-IGGCAS model (Global CoupledIonosphere–Thermosphere–Electrodynamics Model, Institute of Geology and Geophysics, Chinese Academy of Sciences), we simulate theinfluence of atmospheric tide on the annual anomalies of the zonal mean state of the ionospheric electron density, and report that thetidal influence varies with latitude, altitude, and solar activity level. Compared with the density driven by the December tide, the June tidemainly increases lower ionospheric electron densities (below roughly the height of 200 km), and decreases electron densities in thehigher ionosphere (above the height of 200 km). In the low-latitude ionosphere, tides affect the equatorial ionization anomaly structure(EIA) in the relative difference of electron density, which suggests that tides affect the equatorial vertical E×B plasma drifts. Although thetide-driven annual anomalies do not vary significantly with the solar flux level in the lower ionosphere, in the higher ionosphere theannual anomalies generally decrease with solar activity.

关键词： ionospheric annual anomalies atmospheric tide ionosphere–atmosphere coupling

Applying partial correlation method to analyzing the correlation between ionospheric NmF2 and height of isobaric level in the lower atmosphere

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Chinese Science Bulletin 2007年第17期52卷 2413-2419页

作者： XU GuiRong wan weixing NING BaiQi Institute of Geoloqy 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

On the basis of a multiple linear regression model performed for ionospheric NmF2, partial correlation method is first applied to investigating the relation between NmF2 and h (the height of isobaric level) in the lower atmosphere over Wuhan, China during 1957―2004. The results show that partial correlation method can eliminate the influences of solar and geomagnetic activities as well as the seasonal varia- tion factors and reveal the true correlation between NmF2 and h in the lower atmosphere. A weak posi- tive correlation between NmF2 and h is found in the middle stratosphere. In addition, by comparing the partial correlation coefficients between NmF2 and its influence factors, we find that NmF2 is mainly affected by solar activity and the seasonal variation factors, and weakly affected by geomagnetic ac- tivity, but hardly affected by h in the lower atmosphere. The study suggests that partial correlation method is a helpful tool for investigating the correlation between ionospheric parameter and its influ- ence factors.

关键词：低层大气偏相关方法线性回归模型电离层