检索结果-南通市图书馆

MITM: A new Mars Ionosphere-Thermosphere Model

在线全文

学校读者我要写书评

暂无评论

Earth and planetary physics 2025年第2期9卷 337-345页

作者： ZhiPeng Ren YunBo Liu WeiXing Wan Yong Wei XinAn Yue Key Laboratory of Earth and planetary physics Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China 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 College of Earth and planetary Sciences University of the Chinese Academy of SciencesBeijing 100049China

In this study, we present an innovative Mars Ionosphere-Thermosphere Model(MITM), which is a time-dependent, threedimensional(3-D) model that comprehensively represents the self-consistently coupled thermosphere and ionosphere of Mars within the altitude range of 70-300 km. The model incorporates an extensive range of parameters, including neutral number densities of CO_(2), CO,O, O_(2), N_(2), NO, N(^(2)D), N(^(4)S), Ar, and He;ion number densities of CO_(2)^(+), CO^(+), O^(+), O_(2)^(+), N_(2)^(+), NO^(+), N^(+) ions, and electrons;neutral temperature;and neutral wind fields. The MITM code employs a high-resolution grid system in a spherical geographical coordinate system, with a horizontal resolution of 5° latitude by 7.5° longitude. This altitude-resolved grid system enables accurate depiction of spatial variations in the Martian thermosphere and ionosphere. To showcase the capabilities of the MITM, we present two simulation cases: one during the equinox and another during the solstice. Both simulations reproduce key features of the Martian thermosphere and ionosphere including the characteristics of horizontal circulation, diurnal variations in chemical composition, and distribution of electron density. The MITM offers a robust framework for understanding the intricate interactions and processes that shape the Mars thermosphere and ionosphere,which are crucial for enhancing our understanding of Martian upper atmosphere and ionosphere.

关键词： Mars thermosphere ionosphere modeling

Spatiotemporal evolution of wildfire activity during the Paleocene-Eocene Thermal Maximum in China

在线全文

学校读者我要写书评

暂无评论

Science China Earth Sciences 2025年第2期68卷 509-522页

作者： Xue-Ting WANG Zuoling CHEN Linlin CUI Xu WANG State Key Laboratory of Lithospheric and Environmental Coevolution Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China University of Chinese Academy of Sciences College of Earth and Planetary SciencesBeijing 100049China institute of Geology and geophysics Chinese Academy of SciencesBeijing 100029China

The Paleocene-Eocene Thermal Maximum(PETM)was the most prominent warming event in the Cenozoic and serves as a geological analog for the current global warming driven by anthropogenic CO_(2)emissions from burning fossil *** a primary disruptor of Earth's ecosystems,wildfire activity affects the balance of ecosystems,the global carbon cycle,and climate ***,studying the evolution and driving mechanisms of wildfires during the PETM is essential for predicting wildfire activity under global warming scenarios and for understanding the carbon cycle in the context of wildfire *** research on wildfires during the PETM has mainly focused on the Northern Hemisphere,particularly Europe and North America,whereas studies on Chinese mainland remain *** this study,we analyzed black carbon(BC)concentration and carbon isotope(δ13C)in the Beigou section of the Nanyang Basin and the Xilutian section of the Fushun Basin to reconstruct the spatiotemporal evolution of wildfires in arid/semi-arid and humid *** integrated these findings with those of previous studies on the paleoclimate of the research area to elucidate the driving mechanisms behind wildfire *** results indicate that wildfire activity weakened at the onset of the PETM,with the negative carbon isotope period characterized by low wildfire activity,except for a brief resurgence in the Nanyang *** the recovery phase of the PETM,wildfire activity gradually increased,returning to the pre-PETM *** prolonged low wildfire state was likely caused by extremely high temperatures and precipitation as well as the resulting vegetation *** the PETM recovery phase,increased wildfire activity transformed“short-term carbon sinks”of the biological-atmospheric carbon cycle into“long-term carbon sinks”through the burial of *** process of carbon sink conversion may have acted as a negative feedback mechanism,contributing to carbon sequestration and the e

关键词： PETM Wildfire Carbon cycle Nanyang Basin Fushun Basin

同方期刊数据库

Nujiang Canyon ophiolites(eastern Tibetan Plateau): Records of early Jurassic subduction initiation at passive continental margin of the Lhasa block?

在线全文

学校读者我要写书评

暂无评论

Science China Earth Sciences 2025年第3期68卷 730-749页

作者： Qing QIAN Baolu SUN Feiyu DONG State Key Laboratory of Lithospheric and Environmental Coevolution Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China Key Laboratory of Mineral Resources Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China College of Earth and planetary Sciences University of Chinese Academy of SciencesBeijing 100049China

The formation ages and genesis of the Nujiang Canyon ophiolites in the eastern Tibetan Plateau are still unclear, and it has been debated whether they belong to the Neo-Tethyan or Paleo-Tethyan suture zones. This study exhibits that the Diba and Youba ophiolites in Zogang formed at 190–185 Ma and are of supra-subduction zone(SSZ) type, and belong to the Neo-Tethyan Bangong-Nujiang suture zone. The parental magmas of cumulates in the ophiolites were likely boninitic, and the mantle sources had been metasomatized by subduction fluids and melts derived from subducted sediments with components of ancient continental crust. It is further proposed that subduction initiation in the Bangong-Nujiang oceanic basin developed during the early Jurassic(195–184 Ma) at the northern passive continental margin of the Lhasa block. The inception of subduction beneath the Lhasa block occurred simultaneously along >2000 km length, resulting in synchronous arc granitoids on its northern margin. The early Jurassic ophiolites in the Bangong-Nujiang suture zone represent the fragments of forearc oceanic lithosphere during subduction initiation, which was probably induced by abrupt global plate reorganization during the Pangea breakup.

关键词： Nujiang Canyon ophiolites Early Jurassic Subduction initiation Supercontinent breakup Global plate reorganization

Grounded-source short offset transient electromagnetic method:Theory and applications in deep mineral exploration

在线全文

学校读者我要写书评

暂无评论

Science China Earth Sciences 2025年第2期68卷 626-638页

作者： Guoqiang XUE Xin WU Weiying CHEN Nannan ZHOU Key Laboratory of Mineral Resources Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China College of Earth and planetary Sciences University of Chinese Academy of SciencesBeijing 100049China

The Transient Electromagnetic(TEM)method is a critical geophysical technique for subsurface exploration of metal ore bodies,primarily utilizing either loop or grounded *** Long Offset Transient Electromagnetic(LOTEM)method employs a grounded-source transmitter,relying on a far-source observation mode and plane wave approximation for ***,LOTEM's far-source configuration weakens signal strength,and the plane wave approximation reduces precision,limiting effective detection depth to approximately 1000 m with a comprehensive error of about 15%.Recently,we have developed the grounded-source Short Offset Transient Electromagnetic(SOTEM)method,achieving greater detection depth and accuracy within the 500–2000 m depth range,a crucial interval for mineral resource *** study explores the theoretical framework,instrumentation,data processing,and field applications of *** on a point charge element model,SOTEM accurately computes surface wave effects in EM field calculations,optimized for near-source ***-power,high-resolution,wide-bandwidth exploration equipment and an advanced three-dimensional hybrid inversion technique were also developed to enhance the method's *** of SOTEM to the deep exploration of the Zhou'an Ni-Cu-PGE deposit in Henan Province yielded high-resolution imaging of conductivity structures to about 2.5 km *** results,consistent with existing drill data,delineated mineralized ore bodies from surrounding formations,identified zones of mineralization potential,and suggested extensive resource prospects in the region.

关键词： Far-source observation Plane wave model approximation Grounded-source short-offset transient electromagnetic method Wide-bandwidth exploration equipment Three-dimensional hybrid inversion

Petrogenesis of rodingites along the northern margin of the North China Craton: Constraints from zirconology and whole-rock geochemistry

在线全文

学校读者我要写书评

暂无评论

Science China Earth Sciences 2025年第3期68卷 750-767页

作者： Jing RAN Hao WANG Jinhui YANG Yaoqi YAN Yusheng ZHU Baoquan ZHOU State Key Laboratory of Lithospheric and Environmental Coevolution Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China College of Earth and planetary Sciences University of Chinese Academy of SciencesBeijing 100049China

Rodingite is a metasomatic product formed from various rock types by aqueous fluids, providing a direct record of lithosphere-hydrosphere interactions and serving as a key carrier of surface water into Earth's deep interior(water content >1.5wt.%). Determining the properties of metasomatic fluids is crucial for understanding the petrogenesis of rodingites. In this study,we conducted a detailed study of mineral inclusions, U-Pb ages, trace elements, and Hf-O isotopes of zircon, as well as wholerock geochemical and Sr-Nd-Hf isotopic data on rodingites and associated felsic alkaline veins/dikes along the northern margin of the North China Craton(NMNCC), with aims to elucidate their formation ages, petrogenesis, and geodynamic settings. The results show that zircons from syenite and albite syenite veins/dikes exhibit clear oscillatory zoning, a wide range of Th/U ratios(0.0001–4.073), low concentrations of rare-earth elements(REEs), and low crystallization temperatures(<600℃). These characteristics suggest that the zircons crystallized from fluids separated from late-stage melts during magma evolution. Consequently, the zircon U-Pb ages obtained through Secondary Ion Mass Spectrometry(SIMS) and Laser Ablation Inductively Coupled Plasma Mass Spectrometry(LA-ICPMS) analyses(389.1±3.5 to 390.2±1.6 Ma) record the timing of hydrothermal fluid activity. Zircons within the rodingites contain grandite, hematite, and aqueous fluid inclusions, indicating their formation during rodingitization, with an oxidizing, water-rich fluid acting as the metasomatic agent. SIMS and LA-ICPMS analyses of these zircons yielded U-Pb ages of 388.1±3.9 and 388.6±4.6 Ma, which register the formation ages of the rodingites. Both the syenite and albite syenite samples display high total alkali contents(9.9–13.9 wt.%), consistent initial Sr isotopic ratios(0.7047–0.7051),negative εNd(t)(-10.1 to-8.5) and εHf(t)(-13.9 to-13.7) values, and slightly elevated zircon δ^(18)O values(6.20‰±0.18‰)compared to

关键词： North China Craton Rodingite Syenite Inclusions Zircon U-Pb age Sr-Nd-Hf-O isotopes

Prospects for Construction New Metamorphic Rock Database in Big Data Epoch

在线全文

学校读者我要写书评

暂无评论

Journal of Earth Science 2025年第2期36卷 450-459页

作者： Bo Liu Mingguo Zhai Institutional Center for Shared Technologies and Facilities Institute of Geology and GeophysicsChinese Academy of Sciences institute of Geology and geophysics Chinese Academy of Sciences College of Earth and planetary Sciences University of Chinese Academy of Sciences

Research into metamorphism plays a pivotal role in reconstructing the evolution of continent,particularly through the study of ancient rocks that are highly susceptible to metamorphic alterations due to multiple tectonic *** the big data era,the establishment of new data platforms and the application of big data methods have become a focus for metamorphic *** progress has been made in creating specialized databases,compiling comprehensive datasets,and utilizing data analytics to address complex scientific ***,many existing databases are inadequate in meeting the specific requirements of metamorphic research,resulting from a substantial amount of valuable data remaining ***,constructing new databases that can cope with the development of the data era is *** article provides an extensive review of existing databases related to metamorphic rocks and discusses data-driven studies in ***,several crucial factors that need to be taken into consideration in the establishment of specialized metamorphic databases are identified,aiming to leverage data-driven applications to achieve broader scientific objectives in metamorphic research.

关键词：

Simulations of electron zebra stripes in the inner radiation belt using a composite empirical electric field model

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science China Earth Sciences 2025年第1期68卷 27-38页

作者： Ziyang WANG Ying LIU Qiugang ZONG Hong ZOU Yuguang YE Xuzhi ZHOU Chao YUE Shan WANG institute of Space physics and Applied Technology Peking UniversityBeijing100871China State Key Laboratory of Lunar and planetary Science Macao University of Science and TechnologyMacao999078China

The phenomenon termed“zebra stripes”manifests as regular patterns in the energy-space(L shell)spectrum of energetic electrons(ranging from tens to hundreds ke V)within the inner radiation *** structures exhibit drift-periodic behavior and commonly arise from large-scale electric field perturbations near the substorm *** this study,we introduce a composite electric field model and replicate the formation,structure,and evolution of zebra stripes using a bounce-averaged test particle code under this electric field ***-resolution measurements of energetic electrons obtained from the Van Allen Probes and the recently launched Macao Science Satellites-1 are used as initial conditions and served to validate our test particle *** analyses between observed data and simulations demonstrate our test particle method's efficacy in capturing zebra stripes'general ***,the composite model proves capable of reproducing realistic variations in the electric field within the inner radiation belt to a certain ***,subtle differences emerge in the flux strength and the positions of *** disparities primarily stem from limitations inherent in the electric field model and the initial conditions of the *** that the model represents an average case,it is conceivable that real-world scenarios may deviate from the average,thereby introducing variations in the observed phenomena.

关键词： Zebra stripes Inner radiation belt Large-scale electric fields Van Allen Probes Macao Science Satellite

Effects of mesoscale gravity waves on sporadic E simulated by a one-dimensional dynamic model

在线全文

学校读者我要写书评

暂无评论

Earth and planetary physics 2025年第1期9卷 1-9页

作者： Xu Zhou ZeZhong Li XinAn Yue LiBo Liu Key Laboratory of Earth and planetary physics/Heilongjiang Mohe National Geophysical Observatory/Beijing National Observatory of Space Environment Institute of Geology and GeophysicsChinese Academy of Sciences(CAS)Beijing 100029China College of Earth and planetary Sciences University of Chinese Academy of SciencesBeijing 100049China CAS Center for Excellence in Comparative Planetology/CAS Key Laboratory of Geospace Environment/Mengcheng National Geophysical Observatory University of Science and Technology of ChinaHefei 230026China

In addition to being driven by tidal winds,the sporadic E(Es)layers are modulated by gravity waves(GWs),although the effects are not yet comprehensively *** this article,we discuss the effects of mesoscale GWs on the Es layers determined by using a newly developed model,MISE-1D(one-dimensional Model of Ionospheric Sporadic E),with low numerical dissipation and high *** by the wind fields resolved by the high-resolution version of the Whole Atmosphere Community Climate Model with thermosphere and ionosphere extension(WACCM-X),the MISE-1D simulation revealed that GWs significantly influence the evolution of the Es layer above 100 km but have a very limited effect at lower *** effects of GWs are diverse and complex,generally including the generation of fluctuating wavelike structures on the Es layer with frequencies similar to those of the *** mesoscale GWs can also cause increases in the density of Es layers,or they can disperse or diffuse the Es layers and increase their *** addition,the presence of GWs is a key factor in sustaining the Es layers in some cases.

关键词： sporadic E ion tidal layer gravity waves numerical simulation

Exploring Boundary Layer physics and Atmospheric Chemistry in Megacities:Insights from the Beijing 325 m Meteorological Tower

在线全文

学校读者我要写书评

暂无评论

Advances in Atmospheric Sciences 2025年第4期42卷 713-730页

作者： Yele SUN Zifa WANG Linlin WANG Xueling CHENG Weiqi XU Yu SHI Wei ZHOU Yan LI Fei HU Zhiqiu GAO Zhongxiang HONG State Key Laboratory of Atmospheric Boundary Layer physics and Atmospheric Chemistry Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China College of Earth and planetary Sciences University of Chinese Academy of SciencesBeijing 100049China

The Beijing 325 m meteorological tower stands as a pivotal research platform for exploring atmospheric boundary layer physics and atmospheric *** a legacy spanning 45 years,the tower has played a crucial role in unraveling the complexities of urban air pollution,atmospheric processes,and climate change in Beijing,*** review paper provides a comprehensive overview of the measurements on the tower over the past two *** long-term comprehensive observations,researchers have elucidated the intricate relationships between anthropogenic emissions,meteorological dynamics,and atmospheric composition,shedding light on the drivers of air pollution and its impacts on public *** vertical measurements on the tower also enable detailed investigations into boundary layer dynamics,turbulent mixing,and pollutant dispersion,providing invaluable data for validating chemical transport *** findings from the tower’s research include the identification of positive feedback mechanisms between aerosols and the boundary layer,the characterization of pollutant sources and transport pathways,the determination of fluxes of gaseous and particulate species,and the assessment of the effectiveness of pollution control ***,isotopic measurements have provided new insights into the sources and formation processes of particulate matter and reactive nitrogen ***,the paper outlines future directions for tower-based research,emphasizing the need for long-term comprehensive measurements,the development of innovative tower platforms,and integration of emerging technologies.

关键词： meteorological tower boundary layer physics aerosol composition vertical distributions formation mechanisms aerosol-boundary interactions