The characteristics of microphysical profiles of liquid clouds(i.e.,the cloud effective radius(ER)and liquid water content(LWC))are important factors in understanding the aerosol-cloud-precipitation process and improv...The characteristics of microphysical profiles of liquid clouds(i.e.,the cloud effective radius(ER)and liquid water content(LWC))are important factors in understanding the aerosol-cloud-precipitation process and improving the evaluation of cloud radiative effects on a global scale.However,the profiling of clouds is limited to measurements such as radars or lidars,and retrievals from active sensors are influenced by the attenuation of signals and surface clutter.Even when vast amounts of cloud property retrievals that express column or cloud-top/base characteristics from passive sensors are generated,these two-dimensional cloud products are scarcely ever used to further produce three-dimensional cloud profiles because of the lack of a reasonable analytical model to bridge the gap.Thus,this study developed a cloud profile reconstruction model(CPRM)based on our previous analytical cloud profile model and evaluated the sensitivities of visible-to-infrared bands of passive cloud observation sensors to each parameter of the model.The results indicated that the optical thickness,cloud-top ER,and geometrical thickness can be derived from multiwavelength measurements,whereas the slope of the cloud droplet number concentration(CDNC)and the cloud-base ER could hardly be directly estimated.Meanwhile,the analytical model was utilized to rebuild cloud profiles seen by CloudSat and Aircrafts.The analytical model could capture the shape and the vertical variations of the cloud ER and LWC.展开更多
In monitoring and predicting high-impact weather(HIW)events,targeted atmospheric temperature and moisture sounding observations in sensitive areas are more valuable than conventional observations.The conditional nonli...In monitoring and predicting high-impact weather(HIW)events,targeted atmospheric temperature and moisture sounding observations in sensitive areas are more valuable than conventional observations.The conditional nonlinear optimal perturbation(CNOP)method and the linear singular vector(SV)method can be employed to identify these weather-sensitive areas for targeted observations.Such observations can be conducted by using hyperspectral infrared sounders onboard geostationary weather satellites.The Geostationary Interferometric Infrared Sounder(GIIRS)onboard China's Fengyun(FY)-4geostationary satellite series can provide atmospheric sounding observations with a temporal resolution of up to 15 min over areas prone to active weather events.GIIRS offers unprecedented opportunities for targeted observations,enabling flexible measurement modes that focus on weather-sensitive areas.High-temporal-resolution measurements not only reveal the threedimensional(3D)thermodynamic structure of the atmosphere,but also track moisture characteristics to capture the 3D dynamic structure.Moreover,high-temporal-resolution measurements of clear radiances can enhance atmospheric sounding retrievals(used for HIW situation awareness)and data assimilation(used to improve numerical weather prediction).The four-dimensional variational(4D-Var)system facilitates the utilization of the high-temporal-resolution GIIRS targeted observations.In this study,we explore the applications of FY-4A and FY-4B GIIRS targeted observations and focus on data assimilation based on the 4DVar system for improving HIW forecasts.Several typhoon cases are selected for impact analysis.Moreover,we compare CNOP and SV methods for identifying sensitive areas,and use the 4D-Var assimilation system of the Global Assimilation Forecasting System of the China Meteorological Administration(CMA-GFS)for real-time data assimilation.The results indicate hightemporal-resolution observations positively impact typhoon forecasts,with higher temporal resolution yielding greater benefits.This highlights the substantial value of FY-4 GIIRS targeted observations in forecasting HIW events.展开更多
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 foss...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 fuels.As a primary disruptor of Earth's ecosystems,wildfire activity affects the balance of ecosystems,the global carbon cycle,and climate change.Therefore,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 disturbances.Current research on wildfires during the PETM has mainly focused on the Northern Hemisphere,particularly Europe and North America,whereas studies on Chinese mainland remain limited.In 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 zones.We integrated these findings with those of previous studies on the paleoclimate of the research area to elucidate the driving mechanisms behind wildfire occurrences.Our 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 Basin.During the recovery phase of the PETM,wildfire activity gradually increased,returning to the pre-PETM levels.The prolonged low wildfire state was likely caused by extremely high temperatures and precipitation as well as the resulting vegetation succession.During 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 BC.This process of carbon sink conversion may have acted as a negative feedback mechanism,contributing to carbon sequestration and the eventual recovery from the PETM.展开更多
The Changning region,located in the southern Sichuan Basin,has historically been regarded as tectonically stable.However,in recent years,seismicity has increased significantly alongside the expansion of large-scale in...The Changning region,located in the southern Sichuan Basin,has historically been regarded as tectonically stable.However,in recent years,seismicity has increased significantly alongside the expansion of large-scale industrial activities.The successive occurrences of the Xingwen MS5.7 and Changning MS6.0 earthquakes within a short interval have attracted considerable attention from both the seismological community and the public.To better understand the relationship between industrial activities and subsurface velocity structures,as well as their influence on seismicity,this study first selects a large number of high-quality P-and S-wave first arrival times from a dense array of temporary broadband seismic stations,and then conducts local earthquake traveltime tomography to invert for high-resolution P-and S-wave velocity models in the shallow crust beneath the Changning hydraulic fracturing zone.The results reveal that velocity heterogeneities are generally correlated well with stratigraphic age,while localized velocity anomalies near industrial extraction layers are associated with injection pressure variations.Moreover,a low P-wave velocity anomaly forms a continuous belt linking the Xingwen and Changning seismic zones,indicative of a deep subsurface fluid migration channel.Although alternative seismogenic mechanisms cannot be ruled out,this finding preferentially supports a hypothesis in which fluid migration along a long-distance channel activated by the Xingwen earthquake contributes to the initiation of the Changning earthquake.展开更多
A climatological survey of Martian ionospheric plasma density irregularities was conducted by exploring the in-situ measurements of the Mars Atmosphere and Volatile EvolutioN(MAVEN) spacecraft. The irregularities were...A climatological survey of Martian ionospheric plasma density irregularities was conducted by exploring the in-situ measurements of the Mars Atmosphere and Volatile EvolutioN(MAVEN) spacecraft. The irregularities were first classified as enhancement, depletion, and oscillation. By checking the simultaneous magnetic field fluctuation, the irregularities have been classified into two types: with or without magnetic signatures. The classified irregularities exhibit diverse global occurrence patterns, as those with magnetic signatures tend to appear near the periphery of the crustal magnetic anomaly(MA), and those without magnetic signatures prefer to appear either inside of the MA or outside of the MA, depending on the type and solar zenith angle. Under most circumstances, the irregularities have a considerable occurrence rate at altitudes above the ionospheric dynamo height(above 200 km), and the magnetization state of the ions seems irrelevant to their occurrence. In addition, the irregularities do not show dependence on magnetic field geometry, except that the enhancement without magnetic signatures favors the vertical field line, implying its equivalence to the localized bulge. Other similarities and discrepancies exist in reference to previous studies. We believe this global survey complements previous research and provides crucial research clues for future efforts to clarify the nature of the Martian ionospheric irregularities.展开更多
High-temperature diffusion of major elements may obscure the records of early and peak metamorphic stages in granulites,while trace elements are more likely to preserve these records due to their lower diffusion rates...High-temperature diffusion of major elements may obscure the records of early and peak metamorphic stages in granulites,while trace elements are more likely to preserve these records due to their lower diffusion rates.Thus,using calibrated REE-based thermobarometers has proved essential for reconstructing these key stages,drawing considerable attention and application from scholars.However,the precision of these thermobarometers depends on including both major and trace elements from coexisting minerals to define the correlation coefficients(A,B,and D) among mineral pairs,indicating that the elemental composition of these pairs can affect the results.Our study examines the mafic-ultramafic granulites in the southern granulite terrain,India,employing integrated methods such as petrography,mineral chemistry,phase equilibrium modeling,and REE-based thermobarometers.We aim to determine their metamorphic conditions and evolutionary history and to identify potential challenges in using REE-based thermobarometers.The garnet,clinopyroxene,and orthopyroxene in the mafic-ultramafic granulite samples display homogeneous compositional profiles,with pronounced Fe-Mg diffusion zones at the interfaces between garnet and clinopyroxene.Conversely,the profiles of trace elements within garnet and clinopyroxene are better preserved.Investigations into Fe-Mg exchange and randomly selected mineral pairs significantly influence the accuracy of REE-based thermobarometers.Fe-Mg exchange can increase in coefficient A,while decreasing coefficient B for light rare earth elements(LREEs) and increasing it for heavy rare earth elements(HREEs),ultimately resulting in overestimations when calculating REE-based thermobarometers.For example,selecting major compositions with an Ex(=(X_(Mg)^(C)-X_(Mg)^(0))/X_(Mg)^(0)×100%;where X_(Mg)^(C) is the value after Fe-Mg exchange,X_(Mg)^(0) is the value before Fe-Mg exchange;X_(Mg)=Mg/(Fe^(2+)+Mg)) value of ~10 for calculation using the REE-in-Grt-Cpx thermobarometer will result in pressures and temperatures being ~10 kbar and 30-40℃ higher than the true values.Random pairing,such as selections based solely on the core or rim of minerals with changes in trace elements,can severely impact the distribution coefficient D,resulting in substantial discrepancies in thermobarometric calculations and potentially producing anomalous results.Thus,to minimize the impact of these factors,it is necessary to first analyze the profiles of major and trace elements in coexisting minerals before applying the REE-based thermobarometers to evaluate the P-T conditions of granulites.Based on this analysis,maj or element compositions less affected by Fe-Mg exchange(such as avoiding the selection of major compositions at the boundaries of minerals) and in relative equilibrium in trace element compositions among coexisting minerals(same growth periods) should be selected for pairing.Furthermore,integrating additional methods should also be considered when applying the REE-based thermobarometers,to prevent the misinterpretation of the P-T conditions obtained.展开更多
1.Introduction.On November 23,2017,an M_(S)5.0 earthquake occurred in Wulong,Chongqing,China,resulting in tens of casualties and considerable economic loss.Geologically,the epicenter of this earthquake was located in ...1.Introduction.On November 23,2017,an M_(S)5.0 earthquake occurred in Wulong,Chongqing,China,resulting in tens of casualties and considerable economic loss.Geologically,the epicenter of this earthquake was located in the transition zone from the Central Chongqing Fold Belt to the southeast,characterized by a low tectonic loading rate.展开更多
The northern Tibetan Plateau is a climatically sensitive zone influenced by monsoon and westerly winds.In summer,water vapor transport can reach Qinghai Lake and the eastern section of the Qilian Mountains;in winter,w...The northern Tibetan Plateau is a climatically sensitive zone influenced by monsoon and westerly winds.In summer,water vapor transport can reach Qinghai Lake and the eastern section of the Qilian Mountains;in winter,westerly winds mainly control the climate.This article compares the wet/dry changes in the region during the mid-Holocene(MH)warm period,the medieval climate anomaly(MCA),the current warm period(CWP),and the future warm period from the perspective of paleoclimate.We found that the MH warm period was mainly affected by the orbit-controlled East Asian summer monsoon,and the region showed warm and humid climate characteristics.The MCA was mainly controlled by solar radiation,and there was a warm and dry phenomenon.The CWP and the future warm period are mainly controlled by the rise in temperature caused by the increase in greenhouse gases,and the climate is becoming more arid.The wet/dry patterns in the CWP and the future warm period in the next century on the northern Tibetan Plateau are similar to those in the MCA.Continued warming will lead to the expansion of the westerly belt and a gradually humid climate.The future wet/dry changes will be more similar to the MH warm period.展开更多
The ocean is the largest active carbon reservoir on Earth. Organic carbon(OC), as the primary species of carbon sequestration in the ocean, plays an important role in the global carbon cycle through its deposition and...The ocean is the largest active carbon reservoir on Earth. Organic carbon(OC), as the primary species of carbon sequestration in the ocean, plays an important role in the global carbon cycle through its deposition and burial. In this study,sedimentary OC data from 5796 stations, together with relevant geochemical and sedimentological parameters in the Bohai Sea,Yellow Sea, and East China Sea(BYES) were used to summarize and elucidate the distribution and burial patterns of sedimentary OC, and assess carbon sink effect of sedimentary OC burial. The results show that the OC content in the sediments of the BYES ranges from 0.00% to 2.12%, with an average content of 0.47%±0.26%. OC content is significantly correlated with finegrained sediments, with an average OC content in mud areas being 39% higher than that in non-mud areas. Modern OC buried in the BYES are mainly deposited in 7 major mud areas, with a total sedimentary OC burial flux of approximately 8.20 Mt C yr^(–1).Among them, the burial flux of biospheric OC is 6.92 Mt C yr^(–1), equivalent to the OC consumption amount of silicate weathering of the 9 major river basins in the eastern China. In its natural state, the annually sequestered OC in the sediments of the eastern China seas is equivalent to 25.37 Mt of atmospheric CO_(2), indicating a significant carbon sink effect. The distribution and burial of terrigenous OC in the BYES are mainly influenced by the large river inputs and complex marine hydrodynamic environment,while human activities such as dam construction have significantly altered the OC burial in these coastal mud areas.展开更多
Cement is a widely used construction material globally.Its manufacturing contributes to anthropogenic CO_(2)emissions significantly.However,its alkaline compounds can absorb CO_(2)from the surrounding environment and ...Cement is a widely used construction material globally.Its manufacturing contributes to anthropogenic CO_(2)emissions significantly.However,its alkaline compounds can absorb CO_(2)from the surrounding environment and engage in a carbonation reaction,thereby functioning as a carbon sink.As a major cement producer and consumer,China has an important responsibility to rigorously investigate and accurately account for cement carbon uptake.This study presents a comprehensive analytical model of cement carbon uptake from China,revealing a substantial increase in carbon uptake from 1930 to 2021,peaking at 426.77 Mt CO_(2)(95% Confidence Interval:317.67-874.33 Mt CO_(2))in 2021.The uptake accounts for 8.10% to 45.40% of China’s annual land sink and 2.51% to 4.54% of the global land sink.The cumulative carbon uptake by cement is approximately 7.06 Gt CO_(2)(95%CI:5.22–9.44 Gt CO_(2))during this period,offsetting 50.7% of the total emissions(13.91 Gt CO_(2),95%CI:12.44–17.00 Gt CO_(2))from the cement industry.Notably,cement mortar contributed to most absorption(65.64%).From a life cycle perspective,the service stage of cement materials is the period where the largest CO_(2)sink is formed,accounting for 90.03% of the total.Therefore,the potential for carbon sequestration in cement materials and their waste is enormous.Additionally,the model improves the accuracy of cement carbon accounting,supporting both China and global carbon neutrality assessments.Thus,it is crucial for China to achieve its carbon neutrality goals sooner by prioritizing the environmental benefits of cement materials and wastes,and accelerating the development and commercialization of CO_(2)sequestration technologies for cement and its by-products.展开更多
Carbonate rock chemical weathering carbon sinks reduce the rate of increase of the atmospheric CO_(2)concentration and global warming.However,uncertainty still exists in the estimation results of carbonate rock chemic...Carbonate rock chemical weathering carbon sinks reduce the rate of increase of the atmospheric CO_(2)concentration and global warming.However,uncertainty still exists in the estimation results of carbonate rock chemical weathering carbon sink fluxes(CCSF),and the contributions of climate change and ecological restoration to the CCSF are not clear.To this end,we compiled published site data on ion concentrations in different watersheds in China and used a classical thermodynamic dissolution model to reassess the potential and spatial and temporal patterns of the CCSF in China from 1991 to 2020.We quantified the contributions of temperature(MAT),precipitation(MAP),evapotranspiration(ET),soil water(SM),and the normalized difference vegetation index(NDVI)to the CCSF.The results revealed that(1)China's CCSF was 22.76 t CO_(2)km^(-2)yr^(-1),which was higher than the global average(15.77 t CO_(2)km^(-2)yr^(-1)).The total carbonate rock chemical weathering carbon sink(CCS)was 4772.67×10^(4)t CO_(2),contributing 14.91%of the global CCS through a carbonate rock area of 252.98×10^(4)km^(-2).(2)China's CCSF decreased gradually from southeast to northwest,with values of 33.14,12.93,and7.27 t CO_(2)km^(-2)yr^(-1)in the southern karst,Qinghai-Tibetan karst,and northern karst regions,respectively.(3)The overall CCSF in China exhibited an increasing trend from 1991 to 2020,with a rate of increase of 0.16 t CO_(2)km^(-2)yr^(-1).(4)The contributions of the MAP,MAT,ET,SM,and NDVI to the CCSF were 63.3%,3.02%,27.5%,3.1%,and 3.05%,respectively.Among them,the increase in precipitation was the main contributor to the increase in the CCSF in China over the last 30 years,while the enhancement of ET offset part of the positive contribution of the increase in precipitation to the CCSF.In conclusion,the results of this study provide a systematic quantification of the magnitude,the patterns,and the influencing factors of CCS over a long time series in China.The results are of great significance and provide a reference for the diagnosis and gap analysis of the national and global carbon neutrality capacities.展开更多
Zircon as a multi-objective typomorphic mineral commonly contains diverse trace elements with specific petrogenetic significances.The Hf abundance in zircon is sensitively indicative of melt fractionation during zirco...Zircon as a multi-objective typomorphic mineral commonly contains diverse trace elements with specific petrogenetic significances.The Hf abundance in zircon is sensitively indicative of melt fractionation during zircon growth on one hand,and on another,the Ti content is a robust temperature sensor of zircon crystallization and has been effectively u tilized in thermometric estimation.A Hf-Ti negative correlation was previously reported in igneous zircons,and thus a potential Hf thermometry was then speculated.In this work,we performed reliable electron microprobe(EMP)measurements of Hf and Ti in ultrahigh temperature(UHT)zircons from the North China Craton,in optimizing point,line and grid analysis.The EMP contents of Hf and Ti both show a wide range of fluctuation owing to the smaller probe spot,and some of them are higher than the LAICPMS data.The Hf-Ti correlation in UHT zircons displays dual and thus complicated patterns in contrast with the previous consideration,which implicates some other factors controlling the geochemical behaviors of Hf and Ti in zircons.Generally,the estimated Ti temperatures based on the EMP analyses are obviously higher than the LA-ICPMS outcomes,but are well consistent with the actual peak condition of the parent rock.It explains the common underestimation of Ti temperatures in hightemperature metamorphic rocks,by using LA-ICPMS analyses.展开更多
Global warming has altered the thermodynamic and dynamic environments of climate systems,affecting the biogeochemical processes between the geosphere and atmosphere,which has significant impacts on precipitation extre...Global warming has altered the thermodynamic and dynamic environments of climate systems,affecting the biogeochemical processes between the geosphere and atmosphere,which has significant impacts on precipitation extremes and the terrestrial carbon budget of ecosystems.Existing studies have reported a hook structure for precipitation extreme-temperature relationships but have rarely examined the underlying physical mechanisms.Previous studies have also failed to quantify the impact of precipitation on ecosystem productivity,hindering the assessment of future extreme climatic hazards and potential ecosystem risks.To reveal the thermodynamic driving mechanisms for the formation of global precipitation extremes and ecohydrological effects,this study utilizes over ten multisource datasets(i.e.,satellite,reanalysis,climate model,land surface model,machine learning reconstruction,and flux tower measurements).We first assess the response of water-heat-carbon flux to precipitation extremes and explain the underlying physical mechanisms behind the hook structures in terms of atmospheric thermodynamics and dynamics.Based on outputs from five global climate models(GCMs)under ISIMIP3b,we project future changes in the hook structures as well as their impacts on precipitation extremes.Finally,we discuss the impact of precipitation on the terrestrial carbon budget by using outputs from the CLM4.5 model.The results show that precipitation extremes are usually accompanied by strong exchanges of water and heat and demonstrate a nonlinear relationship between precipitation and ecosystem productivity.The intensity(duration)of extreme precipitation is intensifying(decreasing)over most areas of the globe,whereas three-dimensional precipitation events are becoming more concentrated.Atmospheric dynamics play a key role in shaping the hook structure.The structure is not stable;it shifts under climate change and is projected to result in a 10–40%intensification in precipitation by the end of this century.Moderate levels of precipitation contribute to carbon assimilation in ecosystems,and the response of the carbon budget to precipitation is relatively stable under climate change.展开更多
The ecological environment of the Tibetan Plateau,known as the“Third Pole of the Earth”,is extremely sensitive and fragile.With rapid societal development,environmental problems on the Tibetan Plateau have become pr...The ecological environment of the Tibetan Plateau,known as the“Third Pole of the Earth”,is extremely sensitive and fragile.With rapid societal development,environmental problems on the Tibetan Plateau have become prominent,as it is downwind of the emission sources from densely populated areas in the Middle East and South Asia,and the plateau has become one of the regions significantly affected by transboundary pollutant transmission(including black carbon,BC).The Tibetan Plateau has a long history of life and religious sacrifices,including aromatic plant-burning,which were recorded in the geologic record;therefore,BC can be used as a potential indicator to study the changes in religious activities.In this study,BC analysis was carried out based on the plausible dating framework tested by the AMS14C and137Cs methods on successive sediment cores from Lake Dalzong,an alpine lake in the Gannan Tibetan Autonomous Prefecture,northeast of the Tibetan Plateau.It was found that the BC in the lake sediments mainly accumulated through proximity wet deposition,and its content changes reflected the prevalence of surrounding religious activities.The study results indicate that the area of Lake Dalzong has experienced three periods of enhanced religious activities in the last millennium:1490-1565 CE(mid-Ming Dynasty),1810-1890 CE(late Qing Dynasty),and 1920 CE to the present(since the founding of the Republic of China),and the increase in religious activities on this centennial time scale is a response to concurrent social development.This study is the first to extract information on the variation in religious activities from lake sediments on the Tibetan Plateau,which will help advance the study of the historical context of the Anthropocene on the Tibetan Plateau.展开更多
Satellite carbon dioxide(CO_(2))retrievals provide important constraints on surface carbon fluxes in regions that are undersampled by global in situ networks.In this study,we developed an atmospheric inversion system ...Satellite carbon dioxide(CO_(2))retrievals provide important constraints on surface carbon fluxes in regions that are undersampled by global in situ networks.In this study,we developed an atmospheric inversion system to infer CO_(2)sources and sinks from Orbiting Carbon Observatory-2(OCO-2)column CO_(2)retrievals during 2015–2019,and compared our estimates to five other state-of-the-art inversions.By assimilating satellite CO_(2)retrievals in the inversion,the global net terrestrial carbon sink(net biome productivity,NBP)was found to be 1.03±0.39 petagrams of carbon per year(Pg C yr^(-1));this estimate is lower than the sink estimate of 1.46–2.52 Pg C yr^(-1),obtained using surface-based inversions.We estimated a weak northern uptake of 1.30 Pg C yr-1and weak tropical release of-0.26 Pg C yr^(-1),consistent with previous reports.By contrast,the other inversions showed a strong northern uptake(1.44–2.78 Pg C yr-1),but diverging tropical carbon fluxes,from a sink of 0.77 Pg C yr^(-1) to a source of-1.26 Pg C yr^(-1).During the 2015–2016 El Ni?o event,the tropical land biosphere was mainly responsible for a higher global CO_(2)growth rate.Anomalously high carbon uptake in the northern extratropics,consistent with concurrent extreme Northern Hemisphere greening,partially offset the tropical carbon losses.This anomalously high carbon uptake was not always found in surface-based inversions,resulting in a larger global carbon release in the other inversions.Thus,our satellite constraint refines the current understanding of flux partitioning between northern and tropical terrestrial regions,and suggests that the northern extratropics acted as anomalous high CO_(2)sinks in response to the 2015–2016 El Nino event.展开更多
The Tibetan Plateau is one of the most complicated geographical units worldwide in terms of its tectonic and environmental background.Although a hotspot for continental weathering and carbon cycling studies,accurate d...The Tibetan Plateau is one of the most complicated geographical units worldwide in terms of its tectonic and environmental background.Although a hotspot for continental weathering and carbon cycling studies,accurate determination of the weathering carbon budget is challenging in this area,especially sink and source flux quantification and the controlling mechanisms.Compared with other major rivers on the plateau,the Nujiang River is characterized by less human disturbance and maintains a relatively pristine state.This study investigates the high spatiotemporal resolution hydrochemistry and dual-carbon isotope composition(δ~(13)C_(DIC)andΔ~(14)C_(DIC))of river water in the Nujiang River Basin.The results revealed that the solutes and dissolved inorganic carbon in the river water are predominantly derived from rock weathering by carbonic and sulfuric acids,mainly due to the carbonate weathering process,and significantly enhanced by deep carbon sourcing from hot springs in the fault zone.The average contributions of geological and modern carbon in the main stream of the Nujiang River are 35.2%and 64.8%,respectively,and sulfide oxidation contributes>90%of sulfate ions in the river water.After considering the involvement of sulfuric acid generated by sulfide oxidation during rock weathering,the calculated consumption fluxes of atmospheric CO_(2)by silicate and carbonate weathering in the watershed were decreased by approximately 52.0%and 37.4%,respectively,compared with those calculated ignoring this process.Rock weathering of the Nujiang River Basin is a“CO_(2)sink”on a short time scale,while the participation of sulfuric acid makes it a“CO_(2)source”on a geological time scale.The high-frequency observations of ion concentrations,elemental ratios,and calculated contributions of different rock weathering materials indicate that carbonate rock weathering is more sensitive to temperature and runoff variations than silicate rock weathering,with the solute contribution from carbonate weathering increasing significantly during monsoon period.The material input from different rock types is dominated by the hydrological pathways and water-rock reaction times in the basin.This study reveals the river solute origins and weathering CO_(2)sequestration effect in response to a monsoonal climate in one of the most representative pristine plateau watersheds in the world,which is of great importance for elucidating the weathering control mechanisms and CO_(2)net sourcesink effect in plateau watersheds.展开更多
Mid-high maturity shale oil is the most realistic field for the scale breakthrough of terrestrial shale oil production in China.Generally,three deficiencies hinder shale oil development in China:heavy oil density,smal...Mid-high maturity shale oil is the most realistic field for the scale breakthrough of terrestrial shale oil production in China.Generally,three deficiencies hinder shale oil development in China:heavy oil density,small sweet spot areas,and poor distribution continuity.Thus,identifying the“sweet spots”in shale oil reservoirs is critical for the efficient exploration and development of terrestrial shale oil.This study targets the siltstone type(Class-Ⅱshale oil)and pure shale type(Class-Ⅲshale oil)of the Chang 7 Member in the Ordos Basin,and identifies three stratigraphic units,namely the hydrocarbon accumulation unit,hydrocarbon generation unit,and hydrocarbon retention unit,which together constitute the in-source“shale oil system”.The hydrocarbon accumulation unit is mainly siltstone,where the hydrocarbons are migrated from shales.It has favorable porethroat network connectivity with a pore connectivity ratio of 32–57%,being the siltstone-type sweet spots.The hydrocarbon generation unit is mainly composed of high-TOC mudstone/shale and is the main contributor to in-source hydrocarbon generation and expulsion.This unit has high three-dimensional connectivity(28–30%),as shown by the pore-throat network model,associated with vertical paths for hydrocarbon expulsion.The hydrocarbon retention unit is mainly composed of low-TOC mudstone/shale retaining self-generated and migrated hydrocarbons.The pore connectivity rate is 17–42%,and the pore-throat network connectivity direction is uneven.Light and low-carbon-number hydrocarbons are preferentially trapped or even sealed in small pores of the retention unit,forming the typical mudstone/shale-type sweet spots.In the process called shale oil intrasource migration,the oil migrates in source rocks causing component fractionation,which allows more shale oil to enrich in the hydrocarbon accumulation and retention units to form sweet spots,compared with the hydrocarbon generation unit.The migration paths include the one from mudstone/shale to siltstone interlayers and that from the high-TOC mudstone/shale intervals to the low-TOC intervals.The in-source accumulation of shale oil shows the differentiated enrichment model featuring“high-TOC mudstone/shale generating hydrocarbons,low-TOC mudstone/shale retaining hydrocarbons,siltstone accumulating hydrocarbons and multiple intra-source migration paths”.In the Ordos Basin,the organic-lean(TOC 1–3%)mudstone/shale intervals appear to be the sweet spots of shale oil,where there are abundant medium-short-chain hydrocarbons retained with high flowability.After fracturing stimulation,their production conditions may be even superior to those of siltstones.This proposed idea changes the previous strategy to look for sweet spots in high-TOC intervals derived from the shale gas industry.展开更多
No samples from the Moon’s far side have been returned to Earth.Thus,lunar meteorite study can deepen the understanding of the Moon’s far side(if we can identify which lunar meteorites came from the Moon’s far side...No samples from the Moon’s far side have been returned to Earth.Thus,lunar meteorite study can deepen the understanding of the Moon’s far side(if we can identify which lunar meteorites came from the Moon’s far side).The Northwest Africa(NWA)15528 meteorite is a lunar feldspathic regolith breccia meteorite and we speculated it might originate from the Feldspathic Highlands Terrane(FHT)on the far side of the Moon.Here,we report detailed petrography,major and trace elements,and noble gas(He,Ne,and Ar)isotopes for the clasts and matrix,respectively.The results show that the NWA 15528 lunar meteorite contains diverse clasts,including anorthosite,granulite,basalt,and impact melt clasts.The coarse,wellcrystallized,uniform chemical composition minerals may come from intrusive plutonic rocks.Among the anorthosite clasts,the norite/olivine clasts originate from the deep lunar crust,whereas the other anorthosite clasts are from lunar highlands.The Sm concentrations in NWA 15528 were similar to those in the fourth group of Apollo 16 melt samples,demonstrating that NWA 15528 has a typical plagioclase highland meteorite composition.Compared with the Apollo sample data and remote sensing results,the chemical composition of NWA 15528 indicated strong affinities with the FHT area and ferroan anorthosite(FAN)material from the far side of the Moon.The noble gas isotopic composition of NWA 15528 is consistent with a binary mixture of solar wind and cosmogenic components;during stepwise pyrolytic extractions,we observed that the abundance of cosmogenic components decreased,whereas that of solar wind components increased with increasing temperature.The average cosmic-ray exposure(CRE)age of the matrix and granulite is 42±6 Ma,with a shielding depth in the same range of 10-20 g cm^(−2).The gas retention age of NWA 15528 is 2.14 Ga,and the antiquity age of NWA 15528 is(0.69-0.74)±0.2 Ga(considering 50%40Arm is 40Artrap)which indicates the different clasts of NWA 15528 are assembled after 0.69-0.74 Ga.展开更多
In this study,high-resolution Moho depth and average crustal V_(p)/V_(s) ratio distributions in northeast China were obtained through joint inversion of receiver functions and gravity data.The new joint inversion meth...In this study,high-resolution Moho depth and average crustal V_(p)/V_(s) ratio distributions in northeast China were obtained through joint inversion of receiver functions and gravity data.The new joint inversion method comprehensively considers the complementary imaging strengths of the receiver functions in the vertical direction and the gravity data in the lateral direction.To a certain extent,it can reduce the adverse effects of the receiver function data caused by the sedimentary layers of the basin,the inclination of the Moho,and the structure heterogeneity below the station.In preprocessing the receiver function data,a regularized virtual station network was constructed using the teleseismic receiver function waveform reconstruction method to improve the overall spatial resolution.To filter the gravity data,the velocity structure-guided gravity filtering method and gravity upward continuation were used for the shallower region above the Moho and the deeper region below the lithosphere,respectively.The newly obtained model shows that the Moho depths of the Hailar Basin,Erlian Basin,Sanjiang Basin,and Bohai Bay Basin are slightly shallower than those of the surrounding areas,while the Moho depths of the Greater Xing’an Range,Lesser Xing’an Range,and Zhangguangcai Range are slightly deeper.Compared with previous results,the refined Moho depth distribution obtained in this study has a better correspondence with topographic relief and basin boundaries,and the contrast is more evident across the north-south gravity gradient lineament(NSGL).In the eastern part of the Songliao Basin,the Moho is relatively shallow,and there is a high V_(p)/V_(s) ratio,which may have been caused by the intrusion of hot mantle materials into the crust induced by lateral extension of the Songliao Basin.The high V_(p)/V_(s) ratio of the crust below the Changbaishan volcanic area implies the existence of partial melting in the crust caused by upwelling hot mantle materials.展开更多
Traditional zooarchaeological and archaeobotanical methods based on morphological identification of the excavated faunal and floral remains have been broadly used in reconstructing ancient subsistence economies.Howeve...Traditional zooarchaeological and archaeobotanical methods based on morphological identification of the excavated faunal and floral remains have been broadly used in reconstructing ancient subsistence economies.However,the accuracy and reliability of these methods rely heavily on the preservation state of the remains.By sequencing the ancient DNA of plants,animals,and microorganisms preserved in sediment,sedimentary ancient DNA(sedaDNA)now offers a novel approach for reconstructing the taxa composition dated back to hundreds of thousands of years.Yet,its application in open-air archaeological sites is rarely reported.In this study,we attempted to apply sedaDNA shotgun metagenomics on the archaeological deposits of the Khog Gzung site(an open-air site dated to 3160–2954 cal yr BP)on the Tibetan Plateau,and then compared the reconstructed taxonomic composition to the unearthed remains.Results showed that most of the crops and domestic animals identified by the two approaches,such as barley(Hordeum vulgare)and sheep(Ovis aries),are in general consistent.Some species,such as foxtail millet(Setaria italica),however,were only detected by sedaDNA.In addition,a variety of microorganisms were also detected by the sedaDNA.The two approaches combined revealed diversified food resources at the Khog Gzung site,which included crops such as millet,barley and wheat,domestic animals such as sheep and cattle,and likely also wild animals from fishing and hunting.Our data proves that sedaDNA has a great potential in reconstructing the faunal and floral compositions from archaeological deposits,therefore laying the foundation for its border applications.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.42025504,42175152&42405145)the National Key Research and Development Program of China(Grant No.2023YFB3905900)+2 种基金the Youth Innovation Promotion Association of Chinese Academy of Sciences(Grant No.2021122)the Science and Disruptive Technology Program,AIRCAS(Grant No.E2Z202020F)the Natural Science Foundation of Sichuan Province(Grant No.2024NSFSC0770)。
文摘The characteristics of microphysical profiles of liquid clouds(i.e.,the cloud effective radius(ER)and liquid water content(LWC))are important factors in understanding the aerosol-cloud-precipitation process and improving the evaluation of cloud radiative effects on a global scale.However,the profiling of clouds is limited to measurements such as radars or lidars,and retrievals from active sensors are influenced by the attenuation of signals and surface clutter.Even when vast amounts of cloud property retrievals that express column or cloud-top/base characteristics from passive sensors are generated,these two-dimensional cloud products are scarcely ever used to further produce three-dimensional cloud profiles because of the lack of a reasonable analytical model to bridge the gap.Thus,this study developed a cloud profile reconstruction model(CPRM)based on our previous analytical cloud profile model and evaluated the sensitivities of visible-to-infrared bands of passive cloud observation sensors to each parameter of the model.The results indicated that the optical thickness,cloud-top ER,and geometrical thickness can be derived from multiwavelength measurements,whereas the slope of the cloud droplet number concentration(CDNC)and the cloud-base ER could hardly be directly estimated.Meanwhile,the analytical model was utilized to rebuild cloud profiles seen by CloudSat and Aircrafts.The analytical model could capture the shape and the vertical variations of the cloud ER and LWC.
基金supported by the National Natural Science Foundation of China(Grant Nos.42075155,42205158)the China Meteorological Administration Fengyun Application Pioneering Project(Grant No.FY-APP-2021.0204)。
文摘In monitoring and predicting high-impact weather(HIW)events,targeted atmospheric temperature and moisture sounding observations in sensitive areas are more valuable than conventional observations.The conditional nonlinear optimal perturbation(CNOP)method and the linear singular vector(SV)method can be employed to identify these weather-sensitive areas for targeted observations.Such observations can be conducted by using hyperspectral infrared sounders onboard geostationary weather satellites.The Geostationary Interferometric Infrared Sounder(GIIRS)onboard China's Fengyun(FY)-4geostationary satellite series can provide atmospheric sounding observations with a temporal resolution of up to 15 min over areas prone to active weather events.GIIRS offers unprecedented opportunities for targeted observations,enabling flexible measurement modes that focus on weather-sensitive areas.High-temporal-resolution measurements not only reveal the threedimensional(3D)thermodynamic structure of the atmosphere,but also track moisture characteristics to capture the 3D dynamic structure.Moreover,high-temporal-resolution measurements of clear radiances can enhance atmospheric sounding retrievals(used for HIW situation awareness)and data assimilation(used to improve numerical weather prediction).The four-dimensional variational(4D-Var)system facilitates the utilization of the high-temporal-resolution GIIRS targeted observations.In this study,we explore the applications of FY-4A and FY-4B GIIRS targeted observations and focus on data assimilation based on the 4DVar system for improving HIW forecasts.Several typhoon cases are selected for impact analysis.Moreover,we compare CNOP and SV methods for identifying sensitive areas,and use the 4D-Var assimilation system of the Global Assimilation Forecasting System of the China Meteorological Administration(CMA-GFS)for real-time data assimilation.The results indicate hightemporal-resolution observations positively impact typhoon forecasts,with higher temporal resolution yielding greater benefits.This highlights the substantial value of FY-4 GIIRS targeted observations in forecasting HIW events.
基金supported by the National Key R&D Program of China(Grant No.2022YFF0800800)the Strategic Priority Research Program of CAS(Grant No.XDB0710000)。
文摘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 fuels.As a primary disruptor of Earth's ecosystems,wildfire activity affects the balance of ecosystems,the global carbon cycle,and climate change.Therefore,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 disturbances.Current research on wildfires during the PETM has mainly focused on the Northern Hemisphere,particularly Europe and North America,whereas studies on Chinese mainland remain limited.In 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 zones.We integrated these findings with those of previous studies on the paleoclimate of the research area to elucidate the driving mechanisms behind wildfire occurrences.Our 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 Basin.During the recovery phase of the PETM,wildfire activity gradually increased,returning to the pre-PETM levels.The prolonged low wildfire state was likely caused by extremely high temperatures and precipitation as well as the resulting vegetation succession.During 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 BC.This process of carbon sink conversion may have acted as a negative feedback mechanism,contributing to carbon sequestration and the eventual recovery from the PETM.
基金supported by the National Key Research and Development Program of China(Grant No.2020YFA0710600)the National Natural Science Foundation of China(Grant No.U23A2029)。
文摘The Changning region,located in the southern Sichuan Basin,has historically been regarded as tectonically stable.However,in recent years,seismicity has increased significantly alongside the expansion of large-scale industrial activities.The successive occurrences of the Xingwen MS5.7 and Changning MS6.0 earthquakes within a short interval have attracted considerable attention from both the seismological community and the public.To better understand the relationship between industrial activities and subsurface velocity structures,as well as their influence on seismicity,this study first selects a large number of high-quality P-and S-wave first arrival times from a dense array of temporary broadband seismic stations,and then conducts local earthquake traveltime tomography to invert for high-resolution P-and S-wave velocity models in the shallow crust beneath the Changning hydraulic fracturing zone.The results reveal that velocity heterogeneities are generally correlated well with stratigraphic age,while localized velocity anomalies near industrial extraction layers are associated with injection pressure variations.Moreover,a low P-wave velocity anomaly forms a continuous belt linking the Xingwen and Changning seismic zones,indicative of a deep subsurface fluid migration channel.Although alternative seismogenic mechanisms cannot be ruled out,this finding preferentially supports a hypothesis in which fluid migration along a long-distance channel activated by the Xingwen earthquake contributes to the initiation of the Changning earthquake.
基金supported by the Strategic Priority Research Program of Chinese Academy of Sciences (Grant No.XDB41000000)the National Natural Science Foundation of China (Grant Nos.42374181,42374186,42104169,42104147,41804150,41804153)+6 种基金the Guangdong Basic and Applied Basic Research Foundation (Grant Nos.2021A1515011216,2022A1515011580,2020A1515110242)the Natural Science Foundation of Jiangsu Province (Grant No.BK20180445)the Joint Open Fund of Mengcheng National Geophysical Observatory (Grant No.MENGO-202217)the Science and Technology Project of Shangrao City (Grant No.2021F002)the Key Laboratory of Tropical Atmosphere-Ocean System (Sun Yat-sen University),Ministry of Education,the Fundamental Research Funds for the Central Universitiesthe Opening Funding of Chinese Academy of Sciences dedicated for the Chinese Meridian Projectthe Open Research Project of Large Research Infrastructures of CAS —“Study on the interaction between low/mid-latitude atmosphere and ionosphere based on the Chinese Meridian Project”。
文摘A climatological survey of Martian ionospheric plasma density irregularities was conducted by exploring the in-situ measurements of the Mars Atmosphere and Volatile EvolutioN(MAVEN) spacecraft. The irregularities were first classified as enhancement, depletion, and oscillation. By checking the simultaneous magnetic field fluctuation, the irregularities have been classified into two types: with or without magnetic signatures. The classified irregularities exhibit diverse global occurrence patterns, as those with magnetic signatures tend to appear near the periphery of the crustal magnetic anomaly(MA), and those without magnetic signatures prefer to appear either inside of the MA or outside of the MA, depending on the type and solar zenith angle. Under most circumstances, the irregularities have a considerable occurrence rate at altitudes above the ionospheric dynamo height(above 200 km), and the magnetization state of the ions seems irrelevant to their occurrence. In addition, the irregularities do not show dependence on magnetic field geometry, except that the enhancement without magnetic signatures favors the vertical field line, implying its equivalence to the localized bulge. Other similarities and discrepancies exist in reference to previous studies. We believe this global survey complements previous research and provides crucial research clues for future efforts to clarify the nature of the Martian ionospheric irregularities.
基金supported by the National Natural Science Foundation of China (Grants Nos. 41890831 and 42302223)the State Key Laboratory of Continental Dynamics (Grant No. SKLCD-04)。
文摘High-temperature diffusion of major elements may obscure the records of early and peak metamorphic stages in granulites,while trace elements are more likely to preserve these records due to their lower diffusion rates.Thus,using calibrated REE-based thermobarometers has proved essential for reconstructing these key stages,drawing considerable attention and application from scholars.However,the precision of these thermobarometers depends on including both major and trace elements from coexisting minerals to define the correlation coefficients(A,B,and D) among mineral pairs,indicating that the elemental composition of these pairs can affect the results.Our study examines the mafic-ultramafic granulites in the southern granulite terrain,India,employing integrated methods such as petrography,mineral chemistry,phase equilibrium modeling,and REE-based thermobarometers.We aim to determine their metamorphic conditions and evolutionary history and to identify potential challenges in using REE-based thermobarometers.The garnet,clinopyroxene,and orthopyroxene in the mafic-ultramafic granulite samples display homogeneous compositional profiles,with pronounced Fe-Mg diffusion zones at the interfaces between garnet and clinopyroxene.Conversely,the profiles of trace elements within garnet and clinopyroxene are better preserved.Investigations into Fe-Mg exchange and randomly selected mineral pairs significantly influence the accuracy of REE-based thermobarometers.Fe-Mg exchange can increase in coefficient A,while decreasing coefficient B for light rare earth elements(LREEs) and increasing it for heavy rare earth elements(HREEs),ultimately resulting in overestimations when calculating REE-based thermobarometers.For example,selecting major compositions with an Ex(=(X_(Mg)^(C)-X_(Mg)^(0))/X_(Mg)^(0)×100%;where X_(Mg)^(C) is the value after Fe-Mg exchange,X_(Mg)^(0) is the value before Fe-Mg exchange;X_(Mg)=Mg/(Fe^(2+)+Mg)) value of ~10 for calculation using the REE-in-Grt-Cpx thermobarometer will result in pressures and temperatures being ~10 kbar and 30-40℃ higher than the true values.Random pairing,such as selections based solely on the core or rim of minerals with changes in trace elements,can severely impact the distribution coefficient D,resulting in substantial discrepancies in thermobarometric calculations and potentially producing anomalous results.Thus,to minimize the impact of these factors,it is necessary to first analyze the profiles of major and trace elements in coexisting minerals before applying the REE-based thermobarometers to evaluate the P-T conditions of granulites.Based on this analysis,maj or element compositions less affected by Fe-Mg exchange(such as avoiding the selection of major compositions at the boundaries of minerals) and in relative equilibrium in trace element compositions among coexisting minerals(same growth periods) should be selected for pairing.Furthermore,integrating additional methods should also be considered when applying the REE-based thermobarometers,to prevent the misinterpretation of the P-T conditions obtained.
基金support provided by the National Major Scientific and Technological Infrastructure Project“Numerical Simulator for Earth System”supported by the National Natural Science Foundation of China(Grant No.U2239205)the Open Fund of the State Key Laboratory of Geodesy and Earth’s Dynamics(Grant No.SKLGED2023-4-2)。
文摘1.Introduction.On November 23,2017,an M_(S)5.0 earthquake occurred in Wulong,Chongqing,China,resulting in tens of casualties and considerable economic loss.Geologically,the epicenter of this earthquake was located in the transition zone from the Central Chongqing Fold Belt to the southeast,characterized by a low tectonic loading rate.
基金supported by the Second Tibetan Plateau Scientific Expedition and Research Program(STEP)(Grant No.2019QZKK0202)the National Natural Science Foundation of China(Grant Nos.42371159,42077415)the Program of Introducing Talents of Discipline to University(Grant No.BP0618001)。
文摘The northern Tibetan Plateau is a climatically sensitive zone influenced by monsoon and westerly winds.In summer,water vapor transport can reach Qinghai Lake and the eastern section of the Qilian Mountains;in winter,westerly winds mainly control the climate.This article compares the wet/dry changes in the region during the mid-Holocene(MH)warm period,the medieval climate anomaly(MCA),the current warm period(CWP),and the future warm period from the perspective of paleoclimate.We found that the MH warm period was mainly affected by the orbit-controlled East Asian summer monsoon,and the region showed warm and humid climate characteristics.The MCA was mainly controlled by solar radiation,and there was a warm and dry phenomenon.The CWP and the future warm period are mainly controlled by the rise in temperature caused by the increase in greenhouse gases,and the climate is becoming more arid.The wet/dry patterns in the CWP and the future warm period in the next century on the northern Tibetan Plateau are similar to those in the MCA.Continued warming will lead to the expansion of the westerly belt and a gradually humid climate.The future wet/dry changes will be more similar to the MH warm period.
基金supported by the Laoshan Laboratory (Grant No.LSKJ202204200)the Chinese Offshore Investigation and Assessment Project (Grant No.908~ZC~I~05)+2 种基金the National Natural Science Foundation of China-Shandong Joint Fund for Marine Science Research Centers (Grant No.U1606401)the National Natural Science Foundation of China Shiptime Sharing Project (Grant Nos.42049902,42149902)the Taishan Scholar Program of Shandong (Grant No.tspd20181216)。
文摘The ocean is the largest active carbon reservoir on Earth. Organic carbon(OC), as the primary species of carbon sequestration in the ocean, plays an important role in the global carbon cycle through its deposition and burial. In this study,sedimentary OC data from 5796 stations, together with relevant geochemical and sedimentological parameters in the Bohai Sea,Yellow Sea, and East China Sea(BYES) were used to summarize and elucidate the distribution and burial patterns of sedimentary OC, and assess carbon sink effect of sedimentary OC burial. The results show that the OC content in the sediments of the BYES ranges from 0.00% to 2.12%, with an average content of 0.47%±0.26%. OC content is significantly correlated with finegrained sediments, with an average OC content in mud areas being 39% higher than that in non-mud areas. Modern OC buried in the BYES are mainly deposited in 7 major mud areas, with a total sedimentary OC burial flux of approximately 8.20 Mt C yr^(–1).Among them, the burial flux of biospheric OC is 6.92 Mt C yr^(–1), equivalent to the OC consumption amount of silicate weathering of the 9 major river basins in the eastern China. In its natural state, the annually sequestered OC in the sediments of the eastern China seas is equivalent to 25.37 Mt of atmospheric CO_(2), indicating a significant carbon sink effect. The distribution and burial of terrigenous OC in the BYES are mainly influenced by the large river inputs and complex marine hydrodynamic environment,while human activities such as dam construction have significantly altered the OC burial in these coastal mud areas.
基金supported by the China Association for Science and Technology(Grant Nos.2020201&Y202050)the National Natural Science Foundation of China(Grant Nos.71874097,41921005&41977290)+3 种基金the International Support Program of the President of the Chinese Academy of Sciences(Grant No.2017 VCB 0004)the Beijing Natural Science Foundation(Grant No.JQ 19032)the Liaoning Xingliao Talent Project(Grant No.XLYC1907148)the Major Project of the Institute of Applied Ecology,Chinese Academy of Sciences(Grant No.IAEMP202201)。
文摘Cement is a widely used construction material globally.Its manufacturing contributes to anthropogenic CO_(2)emissions significantly.However,its alkaline compounds can absorb CO_(2)from the surrounding environment and engage in a carbonation reaction,thereby functioning as a carbon sink.As a major cement producer and consumer,China has an important responsibility to rigorously investigate and accurately account for cement carbon uptake.This study presents a comprehensive analytical model of cement carbon uptake from China,revealing a substantial increase in carbon uptake from 1930 to 2021,peaking at 426.77 Mt CO_(2)(95% Confidence Interval:317.67-874.33 Mt CO_(2))in 2021.The uptake accounts for 8.10% to 45.40% of China’s annual land sink and 2.51% to 4.54% of the global land sink.The cumulative carbon uptake by cement is approximately 7.06 Gt CO_(2)(95%CI:5.22–9.44 Gt CO_(2))during this period,offsetting 50.7% of the total emissions(13.91 Gt CO_(2),95%CI:12.44–17.00 Gt CO_(2))from the cement industry.Notably,cement mortar contributed to most absorption(65.64%).From a life cycle perspective,the service stage of cement materials is the period where the largest CO_(2)sink is formed,accounting for 90.03% of the total.Therefore,the potential for carbon sequestration in cement materials and their waste is enormous.Additionally,the model improves the accuracy of cement carbon accounting,supporting both China and global carbon neutrality assessments.Thus,it is crucial for China to achieve its carbon neutrality goals sooner by prioritizing the environmental benefits of cement materials and wastes,and accelerating the development and commercialization of CO_(2)sequestration technologies for cement and its by-products.
基金supported by the National Natural Science Foundation(Grant Nos.U22A20619,42077455&42367008)the Western Light Cross-team Program of Chinese Academy of Sciences(Grant No.xbzg-zdsys-202101)+3 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant Nos.XDB40000000&XDA23060100)the Guizhou Provincial Science and Technology Projects(Grant No.2022-198)the High-level Innovative Talents in Guizhou Province(Grant Nos.GCC[2022]015-1&2016-5648)the Guizhou Provincial Science and Technology Subsidies(Grant Nos.GZ2019SIG&GZ2020SIG)。
文摘Carbonate rock chemical weathering carbon sinks reduce the rate of increase of the atmospheric CO_(2)concentration and global warming.However,uncertainty still exists in the estimation results of carbonate rock chemical weathering carbon sink fluxes(CCSF),and the contributions of climate change and ecological restoration to the CCSF are not clear.To this end,we compiled published site data on ion concentrations in different watersheds in China and used a classical thermodynamic dissolution model to reassess the potential and spatial and temporal patterns of the CCSF in China from 1991 to 2020.We quantified the contributions of temperature(MAT),precipitation(MAP),evapotranspiration(ET),soil water(SM),and the normalized difference vegetation index(NDVI)to the CCSF.The results revealed that(1)China's CCSF was 22.76 t CO_(2)km^(-2)yr^(-1),which was higher than the global average(15.77 t CO_(2)km^(-2)yr^(-1)).The total carbonate rock chemical weathering carbon sink(CCS)was 4772.67×10^(4)t CO_(2),contributing 14.91%of the global CCS through a carbonate rock area of 252.98×10^(4)km^(-2).(2)China's CCSF decreased gradually from southeast to northwest,with values of 33.14,12.93,and7.27 t CO_(2)km^(-2)yr^(-1)in the southern karst,Qinghai-Tibetan karst,and northern karst regions,respectively.(3)The overall CCSF in China exhibited an increasing trend from 1991 to 2020,with a rate of increase of 0.16 t CO_(2)km^(-2)yr^(-1).(4)The contributions of the MAP,MAT,ET,SM,and NDVI to the CCSF were 63.3%,3.02%,27.5%,3.1%,and 3.05%,respectively.Among them,the increase in precipitation was the main contributor to the increase in the CCSF in China over the last 30 years,while the enhancement of ET offset part of the positive contribution of the increase in precipitation to the CCSF.In conclusion,the results of this study provide a systematic quantification of the magnitude,the patterns,and the influencing factors of CCS over a long time series in China.The results are of great significance and provide a reference for the diagnosis and gap analysis of the national and global carbon neutrality capacities.
基金supported by the National Natural Science Foundation of China(Grant No.41872190)。
文摘Zircon as a multi-objective typomorphic mineral commonly contains diverse trace elements with specific petrogenetic significances.The Hf abundance in zircon is sensitively indicative of melt fractionation during zircon growth on one hand,and on another,the Ti content is a robust temperature sensor of zircon crystallization and has been effectively u tilized in thermometric estimation.A Hf-Ti negative correlation was previously reported in igneous zircons,and thus a potential Hf thermometry was then speculated.In this work,we performed reliable electron microprobe(EMP)measurements of Hf and Ti in ultrahigh temperature(UHT)zircons from the North China Craton,in optimizing point,line and grid analysis.The EMP contents of Hf and Ti both show a wide range of fluctuation owing to the smaller probe spot,and some of them are higher than the LAICPMS data.The Hf-Ti correlation in UHT zircons displays dual and thus complicated patterns in contrast with the previous consideration,which implicates some other factors controlling the geochemical behaviors of Hf and Ti in zircons.Generally,the estimated Ti temperatures based on the EMP analyses are obviously higher than the LA-ICPMS outcomes,but are well consistent with the actual peak condition of the parent rock.It explains the common underestimation of Ti temperatures in hightemperature metamorphic rocks,by using LA-ICPMS analyses.
基金supported by the National Natural Science Foundation of China(Grant No.52009091)the Fundamental Research Funds for the Central Universities(Grant No.2042022kf1221)。
文摘Global warming has altered the thermodynamic and dynamic environments of climate systems,affecting the biogeochemical processes between the geosphere and atmosphere,which has significant impacts on precipitation extremes and the terrestrial carbon budget of ecosystems.Existing studies have reported a hook structure for precipitation extreme-temperature relationships but have rarely examined the underlying physical mechanisms.Previous studies have also failed to quantify the impact of precipitation on ecosystem productivity,hindering the assessment of future extreme climatic hazards and potential ecosystem risks.To reveal the thermodynamic driving mechanisms for the formation of global precipitation extremes and ecohydrological effects,this study utilizes over ten multisource datasets(i.e.,satellite,reanalysis,climate model,land surface model,machine learning reconstruction,and flux tower measurements).We first assess the response of water-heat-carbon flux to precipitation extremes and explain the underlying physical mechanisms behind the hook structures in terms of atmospheric thermodynamics and dynamics.Based on outputs from five global climate models(GCMs)under ISIMIP3b,we project future changes in the hook structures as well as their impacts on precipitation extremes.Finally,we discuss the impact of precipitation on the terrestrial carbon budget by using outputs from the CLM4.5 model.The results show that precipitation extremes are usually accompanied by strong exchanges of water and heat and demonstrate a nonlinear relationship between precipitation and ecosystem productivity.The intensity(duration)of extreme precipitation is intensifying(decreasing)over most areas of the globe,whereas three-dimensional precipitation events are becoming more concentrated.Atmospheric dynamics play a key role in shaping the hook structure.The structure is not stable;it shifts under climate change and is projected to result in a 10–40%intensification in precipitation by the end of this century.Moderate levels of precipitation contribute to carbon assimilation in ecosystems,and the response of the carbon budget to precipitation is relatively stable under climate change.
基金supported by the National Natural Science Foundation of China(Grant Nos.42171150,42130502)the Second Tibetan Plateau Scientific Expedition and Research Program(STEP)(Grant No.2019QZKK0601)。
文摘The ecological environment of the Tibetan Plateau,known as the“Third Pole of the Earth”,is extremely sensitive and fragile.With rapid societal development,environmental problems on the Tibetan Plateau have become prominent,as it is downwind of the emission sources from densely populated areas in the Middle East and South Asia,and the plateau has become one of the regions significantly affected by transboundary pollutant transmission(including black carbon,BC).The Tibetan Plateau has a long history of life and religious sacrifices,including aromatic plant-burning,which were recorded in the geologic record;therefore,BC can be used as a potential indicator to study the changes in religious activities.In this study,BC analysis was carried out based on the plausible dating framework tested by the AMS14C and137Cs methods on successive sediment cores from Lake Dalzong,an alpine lake in the Gannan Tibetan Autonomous Prefecture,northeast of the Tibetan Plateau.It was found that the BC in the lake sediments mainly accumulated through proximity wet deposition,and its content changes reflected the prevalence of surrounding religious activities.The study results indicate that the area of Lake Dalzong has experienced three periods of enhanced religious activities in the last millennium:1490-1565 CE(mid-Ming Dynasty),1810-1890 CE(late Qing Dynasty),and 1920 CE to the present(since the founding of the Republic of China),and the increase in religious activities on this centennial time scale is a response to concurrent social development.This study is the first to extract information on the variation in religious activities from lake sediments on the Tibetan Plateau,which will help advance the study of the historical context of the Anthropocene on the Tibetan Plateau.
基金supported by the Second Tibetan Plateau Scientific Expedition and Research Program(2022QZKK0101)the National Natural Science Foundation of China(Grant Nos.41975140&42105150)。
文摘Satellite carbon dioxide(CO_(2))retrievals provide important constraints on surface carbon fluxes in regions that are undersampled by global in situ networks.In this study,we developed an atmospheric inversion system to infer CO_(2)sources and sinks from Orbiting Carbon Observatory-2(OCO-2)column CO_(2)retrievals during 2015–2019,and compared our estimates to five other state-of-the-art inversions.By assimilating satellite CO_(2)retrievals in the inversion,the global net terrestrial carbon sink(net biome productivity,NBP)was found to be 1.03±0.39 petagrams of carbon per year(Pg C yr^(-1));this estimate is lower than the sink estimate of 1.46–2.52 Pg C yr^(-1),obtained using surface-based inversions.We estimated a weak northern uptake of 1.30 Pg C yr-1and weak tropical release of-0.26 Pg C yr^(-1),consistent with previous reports.By contrast,the other inversions showed a strong northern uptake(1.44–2.78 Pg C yr-1),but diverging tropical carbon fluxes,from a sink of 0.77 Pg C yr^(-1) to a source of-1.26 Pg C yr^(-1).During the 2015–2016 El Ni?o event,the tropical land biosphere was mainly responsible for a higher global CO_(2)growth rate.Anomalously high carbon uptake in the northern extratropics,consistent with concurrent extreme Northern Hemisphere greening,partially offset the tropical carbon losses.This anomalously high carbon uptake was not always found in surface-based inversions,resulting in a larger global carbon release in the other inversions.Thus,our satellite constraint refines the current understanding of flux partitioning between northern and tropical terrestrial regions,and suggests that the northern extratropics acted as anomalous high CO_(2)sinks in response to the 2015–2016 El Nino event.
基金supported by the National Key Research and Development Program of China(Grant No.2020YFA0607700)the National Basic Science Center Program of Natural Science Foundation of China(Grant No.41888101)+2 种基金the National Natural Science Foundation of China(Grant No.41730857)the Key Research Program of the Institute of Geology&Geophysics,CAS(Grant No.IGGCAS-202204)support from the Youth Innovation Promotion Association CAS(Grant No.2019067)。
文摘The Tibetan Plateau is one of the most complicated geographical units worldwide in terms of its tectonic and environmental background.Although a hotspot for continental weathering and carbon cycling studies,accurate determination of the weathering carbon budget is challenging in this area,especially sink and source flux quantification and the controlling mechanisms.Compared with other major rivers on the plateau,the Nujiang River is characterized by less human disturbance and maintains a relatively pristine state.This study investigates the high spatiotemporal resolution hydrochemistry and dual-carbon isotope composition(δ~(13)C_(DIC)andΔ~(14)C_(DIC))of river water in the Nujiang River Basin.The results revealed that the solutes and dissolved inorganic carbon in the river water are predominantly derived from rock weathering by carbonic and sulfuric acids,mainly due to the carbonate weathering process,and significantly enhanced by deep carbon sourcing from hot springs in the fault zone.The average contributions of geological and modern carbon in the main stream of the Nujiang River are 35.2%and 64.8%,respectively,and sulfide oxidation contributes>90%of sulfate ions in the river water.After considering the involvement of sulfuric acid generated by sulfide oxidation during rock weathering,the calculated consumption fluxes of atmospheric CO_(2)by silicate and carbonate weathering in the watershed were decreased by approximately 52.0%and 37.4%,respectively,compared with those calculated ignoring this process.Rock weathering of the Nujiang River Basin is a“CO_(2)sink”on a short time scale,while the participation of sulfuric acid makes it a“CO_(2)source”on a geological time scale.The high-frequency observations of ion concentrations,elemental ratios,and calculated contributions of different rock weathering materials indicate that carbonate rock weathering is more sensitive to temperature and runoff variations than silicate rock weathering,with the solute contribution from carbonate weathering increasing significantly during monsoon period.The material input from different rock types is dominated by the hydrological pathways and water-rock reaction times in the basin.This study reveals the river solute origins and weathering CO_(2)sequestration effect in response to a monsoonal climate in one of the most representative pristine plateau watersheds in the world,which is of great importance for elucidating the weathering control mechanisms and CO_(2)net sourcesink effect in plateau watersheds.
基金funded by the National Natural Science Foundation of China(Grant Nos.41902151,42172180,41830431,and 41902144)the Petro China Scientific Research and Technology Development Project(Grant No.2021DJ1802)。
文摘Mid-high maturity shale oil is the most realistic field for the scale breakthrough of terrestrial shale oil production in China.Generally,three deficiencies hinder shale oil development in China:heavy oil density,small sweet spot areas,and poor distribution continuity.Thus,identifying the“sweet spots”in shale oil reservoirs is critical for the efficient exploration and development of terrestrial shale oil.This study targets the siltstone type(Class-Ⅱshale oil)and pure shale type(Class-Ⅲshale oil)of the Chang 7 Member in the Ordos Basin,and identifies three stratigraphic units,namely the hydrocarbon accumulation unit,hydrocarbon generation unit,and hydrocarbon retention unit,which together constitute the in-source“shale oil system”.The hydrocarbon accumulation unit is mainly siltstone,where the hydrocarbons are migrated from shales.It has favorable porethroat network connectivity with a pore connectivity ratio of 32–57%,being the siltstone-type sweet spots.The hydrocarbon generation unit is mainly composed of high-TOC mudstone/shale and is the main contributor to in-source hydrocarbon generation and expulsion.This unit has high three-dimensional connectivity(28–30%),as shown by the pore-throat network model,associated with vertical paths for hydrocarbon expulsion.The hydrocarbon retention unit is mainly composed of low-TOC mudstone/shale retaining self-generated and migrated hydrocarbons.The pore connectivity rate is 17–42%,and the pore-throat network connectivity direction is uneven.Light and low-carbon-number hydrocarbons are preferentially trapped or even sealed in small pores of the retention unit,forming the typical mudstone/shale-type sweet spots.In the process called shale oil intrasource migration,the oil migrates in source rocks causing component fractionation,which allows more shale oil to enrich in the hydrocarbon accumulation and retention units to form sweet spots,compared with the hydrocarbon generation unit.The migration paths include the one from mudstone/shale to siltstone interlayers and that from the high-TOC mudstone/shale intervals to the low-TOC intervals.The in-source accumulation of shale oil shows the differentiated enrichment model featuring“high-TOC mudstone/shale generating hydrocarbons,low-TOC mudstone/shale retaining hydrocarbons,siltstone accumulating hydrocarbons and multiple intra-source migration paths”.In the Ordos Basin,the organic-lean(TOC 1–3%)mudstone/shale intervals appear to be the sweet spots of shale oil,where there are abundant medium-short-chain hydrocarbons retained with high flowability.After fracturing stimulation,their production conditions may be even superior to those of siltstones.This proposed idea changes the previous strategy to look for sweet spots in high-TOC intervals derived from the shale gas industry.
基金supported by the Strategic Priority Program B of the Chinese Academy of Sciences(Grant No.XDB41010205)the Civil Aerospace Pre-Research Project(Grant No.D020302)+1 种基金the Strategic Priority Program A of the Chinese Academy of Sciences(Grant Nos.XDA17010403 and XDB41010304)the National Natural Science Foundation of China(Grant Nos.42030205 and 41874079).
文摘No samples from the Moon’s far side have been returned to Earth.Thus,lunar meteorite study can deepen the understanding of the Moon’s far side(if we can identify which lunar meteorites came from the Moon’s far side).The Northwest Africa(NWA)15528 meteorite is a lunar feldspathic regolith breccia meteorite and we speculated it might originate from the Feldspathic Highlands Terrane(FHT)on the far side of the Moon.Here,we report detailed petrography,major and trace elements,and noble gas(He,Ne,and Ar)isotopes for the clasts and matrix,respectively.The results show that the NWA 15528 lunar meteorite contains diverse clasts,including anorthosite,granulite,basalt,and impact melt clasts.The coarse,wellcrystallized,uniform chemical composition minerals may come from intrusive plutonic rocks.Among the anorthosite clasts,the norite/olivine clasts originate from the deep lunar crust,whereas the other anorthosite clasts are from lunar highlands.The Sm concentrations in NWA 15528 were similar to those in the fourth group of Apollo 16 melt samples,demonstrating that NWA 15528 has a typical plagioclase highland meteorite composition.Compared with the Apollo sample data and remote sensing results,the chemical composition of NWA 15528 indicated strong affinities with the FHT area and ferroan anorthosite(FAN)material from the far side of the Moon.The noble gas isotopic composition of NWA 15528 is consistent with a binary mixture of solar wind and cosmogenic components;during stepwise pyrolytic extractions,we observed that the abundance of cosmogenic components decreased,whereas that of solar wind components increased with increasing temperature.The average cosmic-ray exposure(CRE)age of the matrix and granulite is 42±6 Ma,with a shielding depth in the same range of 10-20 g cm^(−2).The gas retention age of NWA 15528 is 2.14 Ga,and the antiquity age of NWA 15528 is(0.69-0.74)±0.2 Ga(considering 50%40Arm is 40Artrap)which indicates the different clasts of NWA 15528 are assembled after 0.69-0.74 Ga.
基金supported by the National Key R&D Program of China(Grant No.2022YFF0800701)the National Natural Science Foundation of China(Grant No.U1839205)。
文摘In this study,high-resolution Moho depth and average crustal V_(p)/V_(s) ratio distributions in northeast China were obtained through joint inversion of receiver functions and gravity data.The new joint inversion method comprehensively considers the complementary imaging strengths of the receiver functions in the vertical direction and the gravity data in the lateral direction.To a certain extent,it can reduce the adverse effects of the receiver function data caused by the sedimentary layers of the basin,the inclination of the Moho,and the structure heterogeneity below the station.In preprocessing the receiver function data,a regularized virtual station network was constructed using the teleseismic receiver function waveform reconstruction method to improve the overall spatial resolution.To filter the gravity data,the velocity structure-guided gravity filtering method and gravity upward continuation were used for the shallower region above the Moho and the deeper region below the lithosphere,respectively.The newly obtained model shows that the Moho depths of the Hailar Basin,Erlian Basin,Sanjiang Basin,and Bohai Bay Basin are slightly shallower than those of the surrounding areas,while the Moho depths of the Greater Xing’an Range,Lesser Xing’an Range,and Zhangguangcai Range are slightly deeper.Compared with previous results,the refined Moho depth distribution obtained in this study has a better correspondence with topographic relief and basin boundaries,and the contrast is more evident across the north-south gravity gradient lineament(NSGL).In the eastern part of the Songliao Basin,the Moho is relatively shallow,and there is a high V_(p)/V_(s) ratio,which may have been caused by the intrusion of hot mantle materials into the crust induced by lateral extension of the Songliao Basin.The high V_(p)/V_(s) ratio of the crust below the Changbaishan volcanic area implies the existence of partial melting in the crust caused by upwelling hot mantle materials.
基金supported by the National Natural Science Foundation of China(Grant Nos.41930323,41988101&42101150)the Second Tibetan Plateau Scientific Expedition and Research Program(Grant No.2019QZKK0601)+3 种基金the Strategic Priority Research Program of Chinese Academy of Sciences(Grant No.XDA2004010103)the Youth Innovation Promotion Association of the Chinese Academy of Sciences(Grant No.2022068)the Open Research Fund of TPESER(Grant No.TPESER202202)Carlsberg Foundation(Grant No.CF18-0024)。
文摘Traditional zooarchaeological and archaeobotanical methods based on morphological identification of the excavated faunal and floral remains have been broadly used in reconstructing ancient subsistence economies.However,the accuracy and reliability of these methods rely heavily on the preservation state of the remains.By sequencing the ancient DNA of plants,animals,and microorganisms preserved in sediment,sedimentary ancient DNA(sedaDNA)now offers a novel approach for reconstructing the taxa composition dated back to hundreds of thousands of years.Yet,its application in open-air archaeological sites is rarely reported.In this study,we attempted to apply sedaDNA shotgun metagenomics on the archaeological deposits of the Khog Gzung site(an open-air site dated to 3160–2954 cal yr BP)on the Tibetan Plateau,and then compared the reconstructed taxonomic composition to the unearthed remains.Results showed that most of the crops and domestic animals identified by the two approaches,such as barley(Hordeum vulgare)and sheep(Ovis aries),are in general consistent.Some species,such as foxtail millet(Setaria italica),however,were only detected by sedaDNA.In addition,a variety of microorganisms were also detected by the sedaDNA.The two approaches combined revealed diversified food resources at the Khog Gzung site,which included crops such as millet,barley and wheat,domestic animals such as sheep and cattle,and likely also wild animals from fishing and hunting.Our data proves that sedaDNA has a great potential in reconstructing the faunal and floral compositions from archaeological deposits,therefore laying the foundation for its border applications.
