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Assessing the performance of magnetopause models based on THEMIS data

Earth and Planetary physics 2024年第5期8卷 776-786页

作者： Yang Lin JianYong Lu BaoHang Qu Xi Wang Institute of space Weather School of Atmospheric PhysicsNanjing University of Information Science & Technology

The magnetopause is the boundary between the Earth's magnetic field and the interplanetary magnetic field（IMF）,located where the supersonic solar wind and magnetospheric pressure are in *** empirical models and global magnetohydrodynamic simulations have been used to define the magnetopause,each of these has *** this work,we use15 years of magnetopause crossing data from the THEMIS（Time History of Events and Macroscale Interactions during Substorms）spacecraft and their corresponding solar wind parameters to investigate under which solar wind conditions these models predict more *** analyze the pattern of large errors in the extensively used magnetopause model and show the specific solar wind parameters,such as components of the IMF,density,velocity,temperature,and others that produce these *** is shown that（1） the model error increases notably with increasing solar wind velocity,decreasing proton density,and increasing temperature;（2） when the cone angle becomes smaller or|Bx|is larger,the Shue98 model errors increase,which might be caused by the magnetic reconnection on the dayside magnetopause;（3） when|By|is large,the error of the model is large,which may be caused by the east–west asymmetry of the magnetopause due to magnetic reconnection;（4） when Bzis southward,the error of the model is larger;and（5） the error is larger for positive dipole tilt than for negative dipole tilt and increases with an increasing dipole tilt ***,the global simulation model b Liu ZQ et al.（2015） shows a substantial improvement in prediction accuracy when IMF Bx,By,or the dipole tilt cannot be *** result can help us choose a more accurate model for forecasting the magnetopause under different solar wind conditions.

关键词： magnetopause empirical model global magnetohydrodynamic simulation THEMIS solar wind parameters

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Mshpy23:a user-friendly,parameterized model of magnetosheath conditions

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Earth and Planetary physics 2024年第1期8卷 89-104页

作者： Jaewoong Jung Hyunju Connor Andrew Dimmock Steve Sembay Andrew Read Jan Soucek NASA Goddard space Flight Center GreenbeltMDUSA Department of Astronomy University of MarylandCollege ParkMDUSA Swedish Institude of space physics UppsalaSweden University of Leicester LeicesterUK Institute of atmospheric physics Academy of Sciences of the Czech Republic

Lunar Environment heliospheric X-ray Imager(LEXI)and Solar wind−Magnetosphere−Ionosphere Link Explorer(SMILE)will observe magnetosheath and its boundary motion in soft X-rays for understanding magnetopause reconnection modes under various solar wind conditions after their respective launches in 2024 and *** conditions,namely,plasma density,velocity,and temperature,are key parameters for predicting and analyzing soft X-ray images from the LEXI and SMILE *** developed a userfriendly model of magnetosheath that parameterizes number density,velocity,temperature,and magnetic field by utilizing the global Magnetohydrodynamics(MHD)model as well as the pre-existing gas-dynamic and analytic *** this parameterized magnetosheath model,scientists can easily reconstruct expected soft X-ray images and utilize them for analysis of observed images of LEXI and SMILE without simulating the complicated global magnetosphere ***,we created an MHD-based magnetosheath model by running a total of 14 OpenGGCM global MHD simulations under 7 solar wind densities(1,5,10,15,20,25,and 30 cm)and 2 interplanetary magnetic field Bz components(±4 nT),and then parameterizing the results in new magnetosheath *** compared the magnetosheath model result with THEMIS statistical data and it showed good agreement with a weighted Pearson correlation coefficient greater than 0.77,especially for plasma density and plasma ***,we compiled a suite of magnetosheath models incorporating previous magnetosheath models(gas-dynamic,analytic),and did two case studies to test the *** MHD-based model was comparable to or better than the previous models while providing self-consistency among the magnetosheath ***,we constructed a tool to calculate a soft X-ray image from any given vantage point,which can support the planning and data analysis of the aforementioned LEXI and SMILE missions.A release of the code has been uploaded to a Git

关键词： magnetosheath python modeling

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The dawn−dusk asymmetry in mesosphere and lower thermosphere temperature disturbances during geomagnetic storms at high latitude

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Earth and Planetary physics 2024年第2期8卷 356-367页

作者： GuanChun Wei JianYong Lu Fen Tang JingYuan Li Meng Sun Institute of space Weather School of Atmospheric PhysicsNanjing University of Information Science&TechnologyNanjing 210044China College of Information and Communication National University of Defense TechnologyWuhan 430019China

Utilizing observations by the Sounding of the Atmosphere using Broadband Emission Radiometry(SABER)instrument,we quantitatively assessed the dawn-dusk asymmetry in temperature disturbances within the high-latitude mesosphere and lower thermosphere(MLT)during the main phase of geomagnetic storms in this *** analysis of five geomagnetic superstorm events indicated that during the main phase,negative temperature disturbances were more prevalent on the dawn side than on the dusk side in the high-latitude MLT *** of a statistical analysis of 54 geomagnetic storm events also revealed a notable disparity in temperature disturbances between the dawn and dusk *** high latitudes,38.2%of the observational points on the dawn side exhibited negative temperature disturbances(less than−5 K),whereas on the dusk side,this percentage was only 29.5%.In contrast,at mid-latitudes,these proportions were 34.1%and 36.5%,respectively,showing no significant *** also conducted a statistical analysis of temperature disturbances at different altitudes,which revealed an increase in the proportion of warming disturbances with ***,the proportion of cooling disturbances initially rose with altitude,reaching a peak around 105 km,and subsequently *** temperature disturbance differences could be explained by the day-night asymmetry in vertical wind disturbances during storm conditions.

关键词： dawn dusk asymmetry SABER(Sounding of the Atmosphere using Broadband Emission Radiometry) geomagnetic storms mesosphere and lower thermosphere

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Two decades of fire activity over the PEEX domain:a look from space,with contribution from models and ground-based measurements

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Big Earth Data 2024年第2期8卷 350-396页

作者： Larisa Sogacheva Timo H.Virtanen Anu-Maija Sundström Pekka Kolmonen Mikhail Sofiev Hanna K.Lappalainen Antti Arola Finnish Meteorological Institute Climate Research ProgrammeHelsinkiFinland Finnish Meteorological Institute Space and Earth Observation CentreHelsinkiFinland Institute for atmospheric and Earth System Research/physics Faculty of ScienceUniversity of HelsinkiHelsinkiFinland

It has been suggested that forest fires will become more frequent/intense with changing climate,which would increase aerosol/gas emissions into the atmosphere.A better under-standing of the relations between meteorological conditions,fires,and fire emissions will help estimate the climate response via forest *** this study,we use ERA5 meteor-ological products,including temperature,precipitation,and soil moisture,to explain the frequency of forest fires and the amount of radiant energy released per time unit by burning vegetation(fire radiative power,FRP).We explore the relation-ships between satellite-retrieved fire products and aerosol properties(aerosol optical depth,AOD),carbon monoxide(CO),formaldehyde(HCHO),and nitrogen dioxide(NO_(2))con-centrations over the PEEX domain,which covers different vegetation zones(***/grasslands,forest,arctic tun-dra)of Pan-Eurasia and *** analyse the concentrations of black carbon and absorbing organic carbon using groundbased AErosol RObotic *** analysis covers the months of May to August from 2002 to *** show posi-tive temperature trends in the Northern zone(>65°N)in June and August(1.56°C and 0.64°C,respectively);all statistically significant trends for precipitation and soil moisture are *** can explain increased fire activity in Siberia over the recent years(2019-2022).Over the whole PEEX domain,FC and FRP trends remain insignificant or negative;a decrease in AOD may address those negative *** show that intrasummer variations exist for cropland/grassland fires,which occur most often in May and August,while Siberian forest fires occur more often in July and *** show that CO concentration has been gradually decreasing in the last two decades in May and *** trends are negative in May,June,and over summer for all regions,in July in Europe,China,the Southern zone(<55°N),and the PEEX *** trends are not significant in all ***_(2)trends are positive in May and

关键词： PEEX wild fires satellite trend enhancement ratios

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Understanding the Low Predictability of the 2015/16 El Niño Event Based on a Deep Learning Model

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Advances in atmospheric Sciences 2024年第7期41卷 1313-1325页

作者： Tingyu WANG Ping HUANG Xianke YANG Center for Monsoon System Research Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China National space Science Center Chinese Academy of SciencesBeijing 100190China State Key Laboratory of space Weather National Space Science CenterChinese Academy of SciencesBeijing 100190China College of Plant Science and Technology Huazhong Agricultural UniversityWuhan 430070China

The 2015/16 El Niño event ranks among the top three of the last 100 years in terms of intensity,but most dynamical models had a relatively low prediction skill for this event before the summer ***,the attribution of this particular event can help us to understand the cause of super El Niño–Southern Oscillation events and how to forecast them *** present study applies attribute methods based on a deep learning model to study the key factors related to the formation of this event.A deep learning model is trained using historical simulations from 21 CMIP6 models to predict the Niño-3.4 *** integrated gradient method is then used to identify the key signals in the North Pacific that determine the evolution of the Niño-3.4 *** crucial signals are then masked in the initial conditions to verify their roles in the *** addition to confirming the key signals inducing the super El Niño event revealed in previous attribution studies,we identify the combined contribution of the tropical North Atlantic and the South Pacific oceans to the evolution and intensity of this event,emphasizing the crucial role of the interactions among them and the North *** approach is also applied to other El Niño events,revealing several new precursor *** study suggests that the deep learning method is useful in attributing the key factors inducing extreme tropical climate events.

关键词： ENSO attribution deep learning ENSO prediction extreme El Niño

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Evaluating CMIP6 models in simulating the North Pacific decadal variability in sea surface salinity

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Science China Earth Sciences 2024年第8期67卷 2661-2680页

作者： Jian CHEN Hailong LIU Pengfei LIN Wenrong BAI Chengzu BAI Lu WANG Institute of atmospheric physics Chinese Academy of SciencesBeijing 100029China State Key Laboratory of Geo-Information Engineering Xi’an 710054China Beijing Municipal Climate Center Beijing Meteorological BureauBeijing 100089China space System Department Equipment Department Beijing 100096China

The North Pacific sea surface salinity(SSS)decadal variability(NPSDV)and its potential forcing were evaluated from 25 coupled models of the Coupled Model Intercomparison Project phase 6(CMIP6)considering the prospects for decadal climate *** results indicated that the CMIP6 models generally reproduced the spatial patterns of *** large standard deviation of the SSS anomaly over the strong current regions,such as the Kuroshio-Oyashio Extension(KOE),North Pacific Current(NPC),California Current System(CCS),and Alaskan Coastal Current(ACC),is reflected in the two leading modes of NPSDV:a dipole with out-of-phase loadings in the KOE-NPC versus CCS-ACC and a monopole with positive loading over the *** order of modes is sensitive to individual models that exhibit discrepancies,especially in temporal phases and power *** autoregressive model of order-1 was used to reconstruct the NPSDV with several forcing *** generally weaker influence of forcings in an autoregressive model of order-1 is partly related to the overestimated response time of NPSDV relative to *** NPSDV variances originate from the persistence of SSS anomalies,but the dominant forcing factors are diverse among *** model diversity for the NPSDV simulation mainly arises from the influence of the tropical El Ni?o-Southern Oscillation through teleconnection on the North Pacific Oscillation or Aleutian Low with timescale ***,models that can reproduce the NPSDV well are not dependent on those with larger impacts from the North Pacific oceanic processes.

关键词： North Pacific Sea surface salinity Decadal variability CMIP6 Leading mode

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High-precision temperature retrieval algorithm and verification for mesospheric airglow spectrum photometer

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Science China Earth Sciences 2024年第5期67卷 1639-1651页

作者： Shuqi NIU Haiyang GAO Zhaoai YAN Ke REN Leilei KOU Baichuan JIANG Lingbin BU Key Open Laboratory of Aerosol and Cloud Precipitation of China Meteorological Administration Nanjing 210044China School of atmospheric physics Nanjing University of Information Science and TechnologyNanjing 210044China National space Science Center Chinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100190China

Photometric technology,characterized by its compact structure and relatively high stability,finds wide application in measuring airglow *** instrumentation is anticipated to assume a pivotal role as the primary equipment for extensive network observations of middle and upper atmospheric temperatures in China,thereby providing crucial support for space environmental monitoring and atmospheric dynamic ***,susceptibility to various factors such as instrument inconsistency,variability in observation conditions,and alterations in the background atmospheric environment across different stations poses a challenge,potentially resulting in data inconsistencies in network *** response to these challenges,we propose a multiple-parameter iterative inversion(MPII)algorithm for temperature retrieval based on a mesospheric airglow spectrum photometer(MASP)developed by our research *** algorithm accurately identifies the center of the image circle,corrects image distortion,and thereby obtains an accurate synthetic spectrum reflective of actual *** encompasses five adjustable parameters:sky background light,atmospheric temperature,filter temperature,optical system focal length,and degree of synthetic spectrum *** to traditional methods,significant enhancements in the accuracy of the inverted temperature are *** validate the effectiveness of the MPII algorithm,we conducted combined active and passive remote sensing synchronous measurements using MASP in conjunction with a sodium fluorescence Doppler lidar developed by the National space Science *** utilizing the lidar temperature as a reference,atmospheric background radiation is mitigated from the MASP data,and the temperature is inverted using the MPII *** analysis with the traditional method reveals that temperatures calculated by the MPII algorithm exhibit better consistency than those observed by the lidar.

关键词： Temperature inversion Airglow spectrum photometer Rotational spectral lines Sodium fluorescence Doppler lidar Comparative observations

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Ground-based and additional science support for SMILE

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Earth and Planetary physics 2024年第1期8卷 275-298页

作者： J.A.Carter M.Dunlop C.Forsyth K.Oksavik E.Donovon A.Kavanagh S.E.Milan T.Sergienko R.C.Fear D.G.Sibeck M.Connors T.Yeoman X.Tan M.G.G.T.Taylor K.McWilliams J.Gjerloev R.Barnes D.D.Billet G.Chisham A.Dimmock M.P.Freeman D.-S.Han M.D.Hartinger S.-Y.W.Hsieh Z.-J.Hu M.K.James L.Juusola K.Kauristie E.A.Kronberg M.Lester J.Manuel J.Matzka I.McCrea Y.Miyoshi J.Rae L.Ren F.Sigernes E.Spanswick K.Sterne A.Steuwer T.Sun M.-T.Walach B.Walsh C.Wang J.Weygand J.Wild J.Yan J.Zhang Q.-H.Zhang Planetary Sciences group School of Physics and AstronomyUniversity of LeicesterUniversity RoadLeicesterLE17RHUK Rutherford Appleton Laboratory space Science Technology Facilities CouncilOxfordshireUK School of space and Environment Beihang UniversityBeijing 100191China Key Laboratory of space Environment Monitoring and Information Processing Ministry of Industry and Information TechnologyBeijing 100017China Department of space and Climate physics UCLMullard Space Science LaboratoryHolmbury St.MaryDorkingSurreyRH56NTUK Birkeland Centre for space Science Department of Physics and Technology.University of BergenBergenNorway Department of physics and Astronomy University of Calgary2500 University DriveCalgaryAlbertaCanada T2N 1N4 British Antarctic Survey CambridgeUK Swedish Institute of space physics KirunaSweden West Highfield Campus University of SouthamptonUniversity RoadSO171BJUK Goddard space Flight Center NASAGreenbeltMarylandUSA Athabasca University AthabascaCanada ESTEC European Space AgencyNetherlands University of Saskatchewan SaskatoonCanada The Johns Hopkins University Applied physics Laboratory LaurelMarylandUSA Swedish Institude of space physics UppsalaSE 75121Sweden Tongji University Shanghai 200092China Center for space Plasma physics Space Science Institute4765 Walnut Street Suite BBoulderColorado80301USA Polar Research Institute of China Shanghai 200136China Finnish Meteorological Institute(FMI) Finland Department of Earth and Environmental Sciences(Geophysics) Ludwig Maximilian University of Munich(LMU)MunichTheresienstr.41MunichD-80333Germany Canadian space Agency MontrealCanada GFZ German Research Centre for Geosciences PotsdamGermany Nagoya University Institute for Space Earth Environment ResearchCenter for Integrated Data ScienceNagoyaAichiJP 464-8601 Northumbria University Newcastle upon TyneTyne and WearUK NE18ST National space Science Center Chinese Academy SciencesBeijing 100190China Arctic Geophysics University Centre in Svalbard

The joint European space Agency and Chinese Academy of Sciences Solar wind Magnetosphere Ionosphere Link Explorer(SMILE)mission will explore global dynamics of the magnetosphere under varying solar wind and interplanetary magnetic field conditions,and simultaneously monitor the auroral response of the Northern Hemisphere *** these large-scale responses with medium and fine-scale measurements at a variety of cadences by additional ground-based and space-based instruments will enable a much greater scientific impact beyond the original goals of the SMILE ***,we describe current community efforts to prepare for SMILE,and the benefits and context various experiments that have explicitly expressed support for SMILE can offer.A dedicated group of international scientists representing many different experiment types and geographical locations,the Ground-based and Additional Science Working group,is facilitating these *** include constructing an online SMILE Data Fusion Facility,the discussion of particular or special modes for experiments such as coherent and incoherent scatter radar,and the consideration of particular observing strategies and spacecraft *** anticipate growing interest and community engagement with the SMILE mission,and we welcome novel ideas and insights from the solar-terrestrial community.

关键词： magnetosphere ionosphere magnetosphere-ionosphere coupling ground-based experimentation SMILE conjunctions missions

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Influence of upstream solar wind on magnetic field distribution in the Martian nightside ionosphere

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Earth and Planetary physics 2024年第5期8卷 728-741页

作者： JiaWei Gao ZhaoJin Rong Qi Zhang Anna Mittelholz Chi Zhang Yong Wei 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 Swedish Institute of space physics Department of Earth Sciences Center for space physics and Department of Astronomy Boston University

Using over eight years of Mars Atmosphere and Volatile Evolutio N （MAVEN） data,from November 2014 to May 2023,we have investigated the Martian nightside ionospheric magnetic field distribution under the influence of upstream solar wind drivers,including the interplanetary magnetic field intensity (∣BIMF∣),solar wind dynamic pressure （PSW）,solar extreme ultraviolet flux （EUV）,and Martian seasons （Ls）.Our analysis reveals pronounced correlations between magnetic field residuals and both∣BIMF∣and *** observed with EUV flux and Lswere weaker—notably,magnetic field residuals increased during periods of high EUV flux and at Mars *** find that the IMF penetrates to an altitude of 200 km under a wide range of upstream conditions,penetrating notably deeper under high∣BIMF∣*** analysis also indicates that EUV flux and IMF cone angle have minimal impact on IMF penetration *** findings provide useful constraints on the dynamic nature of Martian atmospheric escape processes and their evolution,suggesting that historical solar wind conditions may have facilitated deeper IMF penetration and higher rates of ionospheric escape than are observed ***,by establishing criteria for magnetic‘quiet’conditions,this study offers new insights into the planet’s magnetic environment under varying solar wind influences,knowledge that should help refine models of the Martian crustal magnetic field.

关键词： Martian magnetic field external magnetic field upstream solar wind drivers IMF penetration altitude magnetic field activity indices

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Are Solar Active Regions Born with Neutralized Currents?

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Research in Astronomy and Astrophysics 2024年第7期24卷 79-88页

作者： Aiying Duan Yaoyu Xing Chaowei Jiang Planetary Environmental and Astrobiological Research Laboratory(PEARL) School of Atmospheric SciencesSun Yat-sen UniversityZhuhai 519000China Yunnan Key Laboratory of the Solar physics and space Science Kunming 650216China Key Laboratory of Tropical Atmosphere-Ocean System Sun Yat-sen UniversityMinistry of EducationZhuhai 519000China Institute of space Science and Applied Technology Harbin Institute of TechnologyShenzhen 518055China

Solar active regions(ARs)are formed by the emergence of current-carrying magnetic flux tubes from below the *** for an isolated flux tube the direct and return currents flowing along the tube should balance with each other,it remains controversial whether such a neutralization of currents is also maintained during the emergence *** we present a systematic survey of the degrees of the current neutralization in a large sample of flux-emerging ARs which appeared on the solar disk around the central meridian from 2010 to *** vector magnetograms taken by Helioseismic and Magnetic Imager onboard Solar Dynamic Observatory are employed to calculate the distributions of the vertical current density at the *** on the main phase of flux emergence,i.e.,the phase in which the total unsigned magnetic flux is continuously increased,we statistically examined the ratios of direct to return currents in all the *** a large-sample statistical study suggests that most of the ARs were born with currents close to *** degree of current neutralization seems to be not affected by the active-region size,the active-region growing rate,and the total unsigned *** only correlation of significance as found is that the stronger the magnetic field nonpotentiality is,the further the AR deviates from current neutrality,which supports previous event studies that eruption-productive ARs often have non-neutralized currents.

关键词： Sun magnetic fields-Sun flares-Sun corona-Sun coronal mass ejections(CMEs)

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