Marine carbonates,the major carrier of carbon upon the upper crust,can be subducted into the Earth’s interior along with oceanic crust,and then returned to the surface through magmatism,which constitute the deep carb...Marine carbonates,the major carrier of carbon upon the upper crust,can be subducted into the Earth’s interior along with oceanic crust,and then returned to the surface through magmatism,which constitute the deep carbon cycle.This process plays an important role in modulating the CO_(2) concentrations in the atmosphere over geologic time,and thus the forming of the habitable earth.Therefore,identifying recycled marine carbonates in the mantle is critical to well understand the global deep carbon cycle.Calcium is one of the major constituent cations in marine carbonates and its isotopes may be a potential tracer for recycled marine carbonates in the mantle.To further evaluate the capability and challenges of Ca isotopes as such a geochemical tracer,we reviewed the Ca isotopic compositions in important reservoirs and the behavior of Ca isotopes during high-temperature geological processes that are related to the deep carbon cycle,including plate subduction,mantle metasomatism,mantle partial melting,magma differentiation,etc.Available studies show that carbonate-rich marine sediments have significantly lowerδ^(44/40) Ca than the Earth mantle,and metasomatism by such recycled materials can cause lighter Ca isotopic compositions in deep mantle-derived rocks than those of the depleted mantle and mid ocean ridge basalts.However,the Ca isotopic fractionation during partial melting of mantle peridotites is small(~0.10‰)and the Ca isotopic fractionation during plate subduction and intermediate-mafic magma evolution is indistinguishable.These investigations suggest that Ca isotopes have great advances in tracing such recycled materials in the mantle.However,other processes(such as the influence by partial melts of eclogites)may induce similar effects on mantle-derived rocks as subducted marine carbonates but still remains debated,and thus further investigations are strongly needed in the future.展开更多
Clay minerals of 34 sediments collected from the northwestern continental shelf of the East China Sea have been determined by X-ray diffraction analysis. The clay mineral distribution is mainly controlled by the sedim...Clay minerals of 34 sediments collected from the northwestern continental shelf of the East China Sea have been determined by X-ray diffraction analysis. The clay mineral distribution is mainly controlled by the sediment source and the dominant circulation pattern. The predominant clay mineral in our study area is illite comprising more than 67% of the whole clay fraction. The highest concentration of illite （〉68%） is found in the southeastern offshore parts beyond the reach of terrigenous input from the Jeju Island. It means that these illites are largely transported by the Kuroshio Current from the South China Sea （SCS）. Smectite is highly concentrated in the northwest middle part and in the outer-shelf mud patch. It seems to be due to the high supply of smectite transported from China where fine-grained sediments are discharged from modern and ancient Huanghe （Yellow） River. The relatively high abundant kaolinite is likely derived from the Changjiang （Yangtze） River via the Taiwan Warm Current. In contrast, large amounts of chlorite and high chlorite/kaolinite ratios occur in the northwestern area, reflecting the transportation by the Yellow Sea Coastal Current from the southern Yellow Sea. The discrimination diagrams clearly show that the sediments in the northwestern East China Sea are ultimately sourced from Chinese rivers, especially from the Huanghe River, whereas the sediment in the northeast part might come from the Jeju Island. The muddy sediments of the Changjiang River＇s submerged delta have much lower 87Sr/S6Sr ratios （0.716 2-0.718 0） than those of the Shandong Peninsular mud wedge （0.721 6-0.724 9）, which are supposed to be originated from the Huanghe River, suggesting the distribution pattern of 87Sr/86Sr ratios as a new tracer to discriminate the provenance of shelf sediments in the study area. The 87Sr/86Sr ratios of the outer-shelf muddy sediments ranged from 0.7169 to 0.7216 in a wide range and was between those of the Huanghe River and Changjiang River sediments, suggesting multiple sources of the sediment in the area.展开更多
About 45%of tungsten,~20%of tin,and~9%of fluorite of known world reserves are associated with Late Mesozoic igneous rocks,Southeast(SE)China.Here we demonstrate that Fogang granite,the largest inland batholith,is main...About 45%of tungsten,~20%of tin,and~9%of fluorite of known world reserves are associated with Late Mesozoic igneous rocks,Southeast(SE)China.Here we demonstrate that Fogang granite,the largest inland batholith,is mainly of A2-type that is commonly found in post-orogenic settings and experienced plate subduction induced metasomatism.In contrast,the Yajishan syenite and Nankunshan granite intruding the Fogang granite~20 Ma later are of A1-type formed in intraplate settings.We found that F-rich fluid fractionation,which could make the decline of Ga/Al ratio,total(Nb+Y+Ce+Zr)and Zr concentrations,Nb/Ta and Zr/Hf ratios,leads to chemical variations of a few Fogang granites changing from A2-type to highly fractionated or I-and S-type granitoids.Crystal and Frich fluid fractionations,as well as crustal contamination most likely derived from the Fogang granite,result in some Nankunshan granites developing from A1-type into A2-type.These late-or post-magmatic processes should be taken into account carefully when discriminating the petrogenetic types of igneous rocks,especially for the A2-type suites.Combining with the distribution of 180-140 Ma A1-and A2-type igneous rocks,rare metal deposits,and fluorite deposits in SE China,we highlight the significant role of slab-released F-rich fluids in formation of A-type suites and subsequent chemical differentiation and rare metal and fluorine mineralization.A model of flat-slab northeastward rollback is thus proposed,in which the subduction front reached somewhere near Fogang and then started to roll back at~165 Ma.The inland Jurassic granites of SE China represent a unique locality for formation of A-type suites and their associated mineralization.These granites are not anorogenic,but they are the result of slab rollback from a flat slab,founding of that slab at shallow levels,and metasomatism of by F-rich fluids related to slab heating by the asthenosphere.展开更多
Cenozoic adakitic rocks in the Gangdese changed from barren continental melts to ore-forming slab melts at * 23 Ma. The distribution and chemical characteristics of the ore-forming adakites point to an association wit...Cenozoic adakitic rocks in the Gangdese changed from barren continental melts to ore-forming slab melts at * 23 Ma. The distribution and chemical characteristics of the ore-forming adakites point to an association with the Ninetyeast Ridge. The subduction of the thick,rigid Ninetyeast Ridge changed the geometry and rheology of the eastern Tibetan Plateau lithosphere and asthenosphere, restrained the eastward escape of asthenospheric mantle as well as continental fragments, and promoted the uplift and building of the Tibetan Plateau, which consequently changed the tectonic and climatic regimes in eastern Asia.展开更多
In an effort to assess the reliability of satellite altimeter systems, the authors conduct a comparative analysis of sea level data that were collected from the TOPEX/POSEIDON (T/P) altimeter and 10 tide gauges (TG) n...In an effort to assess the reliability of satellite altimeter systems, the authors conduct a comparative analysis of sea level data that were collected from the TOPEX/POSEIDON (T/P) altimeter and 10 tide gauges (TG) near the satellite passing ground tracks. The analysis is made using datasets collected from marginal sea regions surrounding the Korean Peninsula at T/P cycles of 2 to 230, which correspond to October 1992 to December 1998. Proper treatment of tidal errors is a very critical step in data processing because the study area has very strong tide. When the T/P data are processed, the procedures of Park and Gamberoni (1995) are adapted to reduce errors associated with the tide. When the T/P data are processed in this way, the alias periods of M2, S2, and K1 constituents are found to be 62.1, 58.7, and 173 days repectively. The compatibility of the T/P and TG datasets are examined at various filtering periods. The results indicate that the low-frequency signals of the T/P data can be interpreted more safely with longer filtering periods (such as up to the maximum selected value of 200 days). When RMS errors for the 200-day low-pass filter period are compared with all 10 tidal stations, the values span the range of 2.8 to 6.7 cm. The results of a correlation analysis for this filtering period also show a strong agreement between the T/P and TG datasets across all stations investigated (e.g.,p- values consistently less than 0.001). Hence according to the analysis, the conclusion is made that the analysis of surface sea level using satellite altimeter data can be made safely with reasonably extended filtering periods such as 200 days.展开更多
Decadal changes in the subseasonal evolution and the phase-locked climatological intraseasonal fluctuation of summertime rainfall over the Korean Peninsula before and after the mid-1990s are investigated.The activity ...Decadal changes in the subseasonal evolution and the phase-locked climatological intraseasonal fluctuation of summertime rainfall over the Korean Peninsula before and after the mid-1990s are investigated.The activity and the migration speed of the monsoon rain band over the East Asian region are altered in the recent decade,resulting in the drier conditions in late spring and the earlier onset of Changma.In early August when a climatological monsoon break was clear in the earlier decade,the precipitation has increased dramatically with a meridional coherency.The response to the enhanced convection over the South China Sea and southeastern China provides a favorable condition for more precipitation in early August through the changes in moisture transport and tropical cyclone passage.展开更多
A number of high-temperature processes(e.g.,melt-rock reactions,metasomatism,partial melting)can produce signifi cant Ca isotopic fractionation and heterogeneity in the mantle,but the mechanism for such fractionation ...A number of high-temperature processes(e.g.,melt-rock reactions,metasomatism,partial melting)can produce signifi cant Ca isotopic fractionation and heterogeneity in the mantle,but the mechanism for such fractionation remains obscure.To investigate the eff ect of mantle partial melting on Ca isotopic fractionation,we reported high-precision Ca isotopic compositions of depleted mid-ocean ridge basalts(MORBs)from the East Pacifi c Rise and Ecuador Rift in the northeastern Pacifi c.Theδ44/40 Ca of these MORB samples exhibit a narrow variation from 0.84‰to 0.88‰with an average of 0.85‰±0.03‰,which are similar to those of reported MORBs(0.83‰±0.11‰)and back-arc basin basalts(BABBs,0.80‰±0.08‰)in literature,but are lower than the estimate value for the bulk silicate Earth(BSE,0.94‰±0.05‰).The lowδ44/40 Ca signatures of MORB samples in this study cannot be caused by fractional crystallization,since intermediate-mafi c diff erentiation has been demonstrated having only limited eff ects on Ca isotopic fractionation.Instead,the off set ofδ44/40 Ca between MORBs and the BSE is most likely produced by mantle partial melting.During this process,the light Ca isotopes are preferentially transferred to the melt,while the heavy ones tend to stay in the residue,which is consistent with the fact thatδ44/40 Ca of melt-depleted peridotites increases with partial melting in literature.The behavior of Ca isotopes during mantle partial melting is closely related to the inter-mineral(Cpx and Opx)Ca isotopic fractionation and melting mineral modes.Mantle partial melting is one of the common processes that can induce lowerδ44/40 Ca values in basalts and Ca isotopic heterogeneity in Earth’s mantle.展开更多
The 1975 Haicheng Ms7.3 earthquake affected whole Korean Peninsula and even Kyushu, Japan. In this paper isoseismal map of this earthquake was drawn for these areas by sorting out and analyzing data systematically col...The 1975 Haicheng Ms7.3 earthquake affected whole Korean Peninsula and even Kyushu, Japan. In this paper isoseismal map of this earthquake was drawn for these areas by sorting out and analyzing data systematically collected, furthermore, the characteristics of the earthquake damage were discussed. In the northern Korean Peninsula, the intensity is V in great majority of this area except local area with intensity VI, and the damage is basically in accordance with typical characteristics of corresponding intensity grade. In the southern Korean Peninsula, the intensity is IV in large part of the area, however, in some big cities such as Seoul etc., not only high buildings shook strongly, but also some people appeared perceptions such as feeling dizzy and so on, and electrical service was interrupted on one or two districts because of transformer tripping. These phenomena could be caused by the effect of long-period wave generated from a large earthquake on far-field.展开更多
Subinertial fluctuation of a strong northward deep current, which is referred to the Dokdo Abyssal Current （DAC） by Chang et al. （2009）, is investigated from current records for about 16.5 and 8.0 months in the Ul...Subinertial fluctuation of a strong northward deep current, which is referred to the Dokdo Abyssal Current （DAC） by Chang et al. （2009）, is investigated from current records for about 16.5 and 8.0 months in the Ulle- ung Interplain Gap of the East/lapan Sea. The current below 300 m is bottom-intensified and has nearly depth-independent flow. Near bottom, the spectral peaks of the current were found near 10, 20, and 60 d. The DAC variability near 10 d and 20 d is reasonably consistent with the linear theory of topographic Rossby waves （TRWs） in the following aspects： （1） The motion is columnar and bottom-intensified; （2） the theo- retical cutoff frequency is similar to the observation; （3） The observation-based angles of the wavenumber vector are in good agreement with the theoretical ones. The wavelengths of the TRWs with periods of near 10 d and 20 d near Dokdo are significantly shorter than those with similar timescales in the open oceans （100-250 km）. It is primarily due to the weak stratification below 300 m in the East Sea. The deep cur- rent fluctuations with periods of near 10 d and 20 d were accompanied by warm events in the upper layer resulting from eddying processes and/or meandering of the Tsushima Warm Current.展开更多
South China is famous for the extensive magmatism and polymetallic mineralization that took place there in the Mesozoic. Shilu is a large porphyry–skarn Cu–Mo deposit in the Yangchun Basin, South China. The litholog...South China is famous for the extensive magmatism and polymetallic mineralization that took place there in the Mesozoic. Shilu is a large porphyry–skarn Cu–Mo deposit in the Yangchun Basin, South China. The lithology of the Shilu intrusion is granodiorite and quartz diorite, both of which are high-K calc-alkaline series, with high Sr([400 ppm) content along with low Y and Yb contents. Most of the samples have characteristics of adakite except for a few samples that have slightly higher Y and Yb contents, which may be plausibly explained by crustal contamination. Laser Ablation Inductively Coupled Plasma Mass Spectrometry zircon U–Pb dating revealed ages between 106.6 ± 1.3 and 103.9 ± 0.5 Ma, with multiple magmatic pulses. Molybdenite Re–Os isochron age of 102.2 ± 2.9 Ma(MSWD = 9.4) was determined, which is identical to the youngest zircon U–Pb age(103.9 ± 0.5 Ma) within error.The Shilu intrusion has high oxygen fugacity as indicated by high zircon Ce^(4+)/Ce^(3+) and Eu_N/Eu_N* ratios. Considering the geochemical characteristics(high Sr, and low Y and Yb contents), high oxygen fugacity, and copper mineralization of the Shilu intrusion, it was most likely formed by partial melting of a subducted young oceanic slab. Whole-rock Sr–Nd isotope-, zircon Hf isotope-, and whole-rock trace element analyses show that Shilu adakitic magmas may have interacted with type II enriched mantle and/or crustal materials during ascent. South China was affected by the Pacific tectonic regime to the east and the Neo-Tethys tectonic regime to the south in the Cretaceous. Based on the Pacific Plate drifting and rotation history, it is hard to explain how the Pacific Plate would have subducted and melted, forming adakitic rocks in the Shilu region. Considering the tectonic history of Southeast Asia and the South China Sea, the Neo-Tethys trench should have been much closer to the South China Block in the Cretaceous, and thus have had a greater impact on the South China Block. Based on the subduction direction, time of subduction,and distance between the Neo-Tethys subduction zone and the Shilu deposit, subduction of the Neo-Tethys ridge is the best mechanism for explaining the Shilu adakitic rocks and Cu–Mo mineralization.展开更多
A series of coesite,coexisting with or without a liquid phase,was synthesized in the nominal system SiO2-H2O at800-1450℃and 5 GPa.Micro-Raman spectroscopy was used to identity the crystalline phase,electron microprob...A series of coesite,coexisting with or without a liquid phase,was synthesized in the nominal system SiO2-H2O at800-1450℃and 5 GPa.Micro-Raman spectroscopy was used to identity the crystalline phase,electron microprobe and LA-ICP-MS were employed to quantity some major and trace elements,and unpolarized FTIR spectroscopy was applied to probe the different types of hydrogen defects,explore water-incorporation mechanisms and quantify water contents.Trace amounts of A1 and B were detected in the coesite.Combining our results with the results in the literatures,we have found no positive correlation between the Al contents and the"Al"-based hydrogen concentrations,suggesting that previously proposed hydrogen-incorporation mechanism H^++Al^3+■Si^4+does not function in coesite.In contrast,we have confirmed the positive correlation between the B contents and the B-based hydrogen concentrations.The hydrogen-incorporation mechanism H^++B3^+■Si^4+readily takes place in coesite at different P-T conditions,and significantly increases the water content at both liquid-saturated and liquid-undersaturated conditions.For the SiO2-H2O system,we have found that type-Ⅰhydrogarnet substitution plays a dictating role in incorporating water into coesite at liquid-saturated condition,type-II hydrogarnet substitution contributes significantly at nearly dry condition,and both operate at conditions in between.The water solubility of coesite,as dictated by the type-Ⅰhydrogarnet substitution,positively correlates with both P and T,cH2O=-105(30)+5.2(32)×P+0.112(26)×T,with cH2O in wt ppm,P in GPa and T in℃.Due to its low water solubility and small fraction in subducted slabs,coesite may contribute insignificantly to the vertical water transport in subduction zones.Furthermore,the water solubility of any coesite in exhuming ultra-high pressure metamorphic rocks should be virtually zero as coesite becomes metastable.With an adequately fast waterdiffusion rate,this metastable coesite should be completely dry,which may have been the key factor to the partial preservation of most natural Coe.As a byproduct,a new IR experimental protocol for accurate water determination in optically anisotropic nominally anhydrous minerals has been found.Aided with the empirical method of Paterson(1982)it employs multiple unpolarized IR spectra,collected from randomly-orientated mineral grains,to approximate both total integrated absorbance and total integrated molar absorption coefficient.Its success relies on a high-level orientation randomness in the IR analyses.展开更多
The plate tectonics theory is a milestone in solid Earth sciences.However,50 years after the theory has been proposed,the driving force behind plate drifts is still controversial(Sun 2016).Slab pull has been accepted ...The plate tectonics theory is a milestone in solid Earth sciences.However,50 years after the theory has been proposed,the driving force behind plate drifts is still controversial(Sun 2016).Slab pull has been accepted as the dominant driving force of plate tectonics for a long time(Forsyth and Uyeda 1975).A major challenge of this model is how plate subduction was initiated in the first place(Arculus et al.2015,2019;Li et al.2019;Niu 2016;Niu et al.2003;O'Connor et al.2015;Sun 2016,2017;Zhou et al.2018).展开更多
Global demand for seafood is constantly increasing,driven by population growth and rising per capita con-sumption.While wild-capture fisheries are facing limitations in meeting this demand,the expansion of aqua-cultur...Global demand for seafood is constantly increasing,driven by population growth and rising per capita con-sumption.While wild-capture fisheries are facing limitations in meeting this demand,the expansion of aqua-culture emerges as the only solution.This paper investigates the potential for increasing the aquaculture production in the Republic of Cyprus by transitioning towards offshore aquaculture farms.The model developed provides a valuable roadmap for offshore transitions in Mediterranean near-coast areas.The study includes a detailed economic analysis coupled with sensitivity analysis to assess the feasibility of this transition considering various expansion scenarios.The results provide valuable insights into the viability and implications of this process,highlighting economic and operational issues.展开更多
Granitic continental crust distinguishes the Earth from other planets in the Solar System. Consequently, for understanding terrestrial continent development, it is of great significance to investigate the formation an...Granitic continental crust distinguishes the Earth from other planets in the Solar System. Consequently, for understanding terrestrial continent development, it is of great significance to investigate the formation and evolution of granite.Crystal fractionation is one of principal magma evolution mechanisms. Nevertheless, it is controversial whether crystal fractionation can effectively proceed in felsic magma systems because of the high viscosity and non-Newtonian behavior associated with granitic magmas. In this paper, we focus on the physical processes and evaluate the role of crystal fractionation in the evolution of granitic magmas during non-transport processes, i.e., in magma chambers and after emplacement. Based on physical calculations and analyses, we suggest that general mineral particles can settle only at tiny speed(~10^(-9)–10^(-7) m s^(-1))in a granitic magma body due to high viscosity of the magma; however, the cumulating can be interrupted with convection in magma chambers, and the components of magma chambers will tend to be homogeneous. Magma convection ceases once the magma chamber develops into a mush(crystallinity, F>~40–50%). The interstitial melts can be extracted by hindered settling and compaction, accumulating gradually and forming a highly silicic melt layer. The high silica melts can further evolve into high-silica granite or high-silica rhyolite. At various crystallinities, multiple rejuvenation of the mush and the following magma intrusion may generate a granite complex with various components. While one special type of granites, represented by the South China lithium-and fluoride-rich granite, has lower viscosity and solidus relative to general granitic magmas, and may form vertical zonation in mineral-assemblage and composition through crystal fractionation. Similar fabrics in general intrusions that show various components on small lengthscales are not the result of gravitational settling. Rather, the flowage differentiation may play a key role. In general, granitic magma can undergo effective crystal fractionation; high-silica granite and volcanics with highly fractionated characteristics may be the products of crystal fractionation of felsic magmas, and many granitoids may be cumulates.展开更多
High-precision(±0.1 ppm) and high-frequency(hourly averaged) in situ measurements of atmospheric carbon dioxide(CO2) were made for the first time from August 2005 to July 2007 at Yanbian,China using a non-dispers...High-precision(±0.1 ppm) and high-frequency(hourly averaged) in situ measurements of atmospheric carbon dioxide(CO2) were made for the first time from August 2005 to July 2007 at Yanbian,China using a non-dispersive Infrared(NDIR) analyzer with National Oceanic and Atmospheric Administration/Earth System Research Laboratory(NOAA/ESRL) standards.The results of these measurements are presented in this paper and are used to investigate the regional representativeness of regional background data at Yanbian and determine the CO2 emission source regions in Northeast Asia.The phase of the monthly variations at Yanbian reflects the special regional characteristics,which were overall in excellent agreement with other observatories in the middle-to-high latitudes in the Northern Hemisphere.Applying a hybrid receptor model to the regional emission source events in cold period(November-April),we estimated the distribution of the major CO2 emissions in the northeast Asia.The results indicated that the strongest potential emission areas contributing to Yanbian are the Beijing & Tianjin metropolitan areas,southwestern part of Shandong Province including Jinan,and Vladivostok.The results of this study reveal the usefulness of in situ CO2 measurements at Yanbian in establishing the scientific foundation for monitoring the large CO2 emission areas in northern China and Russia.Continued monitoring of CO2 at Yanbian within a regional network should provide significant contributions to both understanding the global/regional carbon cycle and constraining "top-down" emissions in Northeast Asia.展开更多
Wet deposition scavenges particles and particle-associated bacteria from the air column, but the impact of raindrops on various surfaces on Earth causes emission of surface-associated bacteria into the air column. Thu...Wet deposition scavenges particles and particle-associated bacteria from the air column, but the impact of raindrops on various surfaces on Earth causes emission of surface-associated bacteria into the air column. Thus, after rainfall, these two mechanisms are expected to cause changes in airborne bacterial community composition （BCC）. In this study, aerosol samples were collected at a suburban site in Seoul, Korea before and after three heavy rainfall events in April, May, and July 2011. BCC was investigated by pyrosequencing the 16S rRNA gene in aerosol samples. Interestingly, the relative abundance of non-spore forming Actinobacteria operational taxonomic units （OTUs） was always higher in post-rain aerosol samples. In particular, the absolute and relative abundances of airborne Propionibacteriaceae always increased after rainfall, whereas those of airborne Firmicutes, including Carnobacteriaceae and Clostridiales, consistently decreased. Marine bacterial sequences, which were temporally important in aerosol samples, also decreased after rainfall events. Further, increases in pathogen-like sequences were often observed in post-rain air samples. Rainfall events seemed to affect airborne BCCs by the combined action of the two mechanisms, with potentially adverse effects on human and plant health.展开更多
This study reports on the first investigation into the potential of luminescence dating to establish a chronological framework for the depositional sequences of the Sperchios delta plain, central Greece. A series of t...This study reports on the first investigation into the potential of luminescence dating to establish a chronological framework for the depositional sequences of the Sperchios delta plain, central Greece. A series of three borehole cores(20 m deep) and two shallow cores(4 m deep), from across the delta plain, were extracted, and samples were collected for luminescence dating. The luminescence ages of sand-sized quartz grains were obtained from small aliquots of quartz, using the Single-Aliquot Regenerative-dose(SAR) protocol.The equivalent dose determination included a series of tests and the selection of the Minimum Age Model(MAM) as the most appropriate statistical model. This made it possible to confirm the applicability of quartz Optically Stimulated Luminescence(OSL) dating to establish absolute chronology for deltaic sediments from the Sperchios delta plain.Testing age results of the five cores showed that the deltaic sediments were deposited during the Holocene.A relatively rapid deposition is implied for the top14 m possibly as a result of the deceleration in the rate of the sea-level rise and the transition to terrestrial conditions, while on the deeper parts, the reduced sedimentation rate may indicate a lagoonal or coastal environment.展开更多
In recent days,discrimination diagrams have been widely used for tracing the tectonic settings and origins of basalts from orogenic belts.However,conventional discrimination diagrams are not accurate enough.Here,we re...In recent days,discrimination diagrams have been widely used for tracing the tectonic settings and origins of basalts from orogenic belts.However,conventional discrimination diagrams are not accurate enough.Here,we reported six new discrimination diagrams obtained from the global database using data mining methods.For most individual diagrams,island arc basalt can be nearly 100%was identified,whereas ocean island basalt and midocean ridge basalt can be discriminated from each other with less than 10%of overlap,under a confidence coefficient of 85%.Using the six new discrimination diagrams together,basalts of different origins can be efficiently identified.展开更多
Estimating horizontal winds in and around typhoons is important for improved monitoring and prediction of typhoons and mitigating their damages.Here,we present a new algorithm for estimating typhoon winds using multip...Estimating horizontal winds in and around typhoons is important for improved monitoring and prediction of typhoons and mitigating their damages.Here,we present a new algorithm for estimating typhoon winds using multiple satellite observations and its application to Typhoon Soulik(2018).Four kinds of satellite remote sensing data,along with their relationship to typhoon intensity,derived statistically from hundreds of historical typhoon cases,were merged into the final product of typhoon wind(MT wind):(1)geostationarysatellite-based infrared images(IR wind),(2)passive microwave sounder(MW wind),(3)feature-tracked atmospheric motion vectors,and (4)scatterometer-based sea surface winds(SSWs).The algorithm was applied to two cases(A and B)of Typhoon Soulik and validated against SSWs independently retrieved from active microwave synthetic aperture radar(SAR)and microwave radiometer(AMSR2)images,and vertical profiles of wind speed derived from reanalyzed data and dropsonde observations.For Case A(open ocean),the algorithm estimated the realistic maximum wind,radius of maximum wind,and radius of 15 m/s,which could not be estimated using the reanalysis data,demonstrating reasonable and practical estimates.However,for Case B(when the typhoon rapidly weakened just before making landfall in the Korean Peninsula),the algorithm significantly overestimated the parameters,primarily due to the overestimation of typhoon intensity.Our study highlights that realistic typhoon winds can be monitored continuously in real-time using multiple satellite observations,particularly when typhoon intensity is reasonably well predicted,providing timely analysis results and products of operational importance.展开更多
Sea surface temperature(SST)retrieved from Advanced Very High Resolution Radiometer(AVHRR)onboard National Oceanic and Atmospheric Administration(NOAA)polar orbiting environmental satellites were validated in the East...Sea surface temperature(SST)retrieved from Advanced Very High Resolution Radiometer(AVHRR)onboard National Oceanic and Atmospheric Administration(NOAA)polar orbiting environmental satellites were validated in the East/Japan Sea(EJS)using surface drifter measurements as ground truths from 2005 to 2010.Overall,the root-mean-square(rms)errors of multichannel SSTs(MCSSTs)and non-linear SSTs(NLSSTs)using global SST coefficients were approximately 0.85℃ and 0.80℃,respectively.An analysis of the SST errors(satellite-drifter)revealed a dependence on the amount of atmospheric moisture.In addition,satellite-derived SSTs tended to be related to wind speeds,particularly during the night.The SST errors also demonstrated diurnal variations with relatively higher rms from 0.80℃ to 1.00℃ during the night than the day,with a small rms of about 0.50℃.Bias also exhibited reasonable diurnal differences,showing small biases during the daytime.Although a satellite zenith angle has been considered in the global SST coefficients,its effect on the SST errors still remained in case of the EJS.Given the diverse use of SST data,the continuous validation and understanding of the characteristic errors of satellite SSTs should be conducted based on extensive in-situ temperature measurements in the global ocean as well as local seas.展开更多
基金Supported by the National Natural Science Foundation of China(Nos.42322302,42373048)the Youth Innovation Promotion Association,Chinese Academy of Sciences(No.2022207)+1 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB42020303)the Laoshan Laboratory(No.LSKJ202204100)。
文摘Marine carbonates,the major carrier of carbon upon the upper crust,can be subducted into the Earth’s interior along with oceanic crust,and then returned to the surface through magmatism,which constitute the deep carbon cycle.This process plays an important role in modulating the CO_(2) concentrations in the atmosphere over geologic time,and thus the forming of the habitable earth.Therefore,identifying recycled marine carbonates in the mantle is critical to well understand the global deep carbon cycle.Calcium is one of the major constituent cations in marine carbonates and its isotopes may be a potential tracer for recycled marine carbonates in the mantle.To further evaluate the capability and challenges of Ca isotopes as such a geochemical tracer,we reviewed the Ca isotopic compositions in important reservoirs and the behavior of Ca isotopes during high-temperature geological processes that are related to the deep carbon cycle,including plate subduction,mantle metasomatism,mantle partial melting,magma differentiation,etc.Available studies show that carbonate-rich marine sediments have significantly lowerδ^(44/40) Ca than the Earth mantle,and metasomatism by such recycled materials can cause lighter Ca isotopic compositions in deep mantle-derived rocks than those of the depleted mantle and mid ocean ridge basalts.However,the Ca isotopic fractionation during partial melting of mantle peridotites is small(~0.10‰)and the Ca isotopic fractionation during plate subduction and intermediate-mafic magma evolution is indistinguishable.These investigations suggest that Ca isotopes have great advances in tracing such recycled materials in the mantle.However,other processes(such as the influence by partial melts of eclogites)may induce similar effects on mantle-derived rocks as subducted marine carbonates but still remains debated,and thus further investigations are strongly needed in the future.
基金This work was supported by the research grant of the Cheju National University of Year 2006.
文摘Clay minerals of 34 sediments collected from the northwestern continental shelf of the East China Sea have been determined by X-ray diffraction analysis. The clay mineral distribution is mainly controlled by the sediment source and the dominant circulation pattern. The predominant clay mineral in our study area is illite comprising more than 67% of the whole clay fraction. The highest concentration of illite （〉68%） is found in the southeastern offshore parts beyond the reach of terrigenous input from the Jeju Island. It means that these illites are largely transported by the Kuroshio Current from the South China Sea （SCS）. Smectite is highly concentrated in the northwest middle part and in the outer-shelf mud patch. It seems to be due to the high supply of smectite transported from China where fine-grained sediments are discharged from modern and ancient Huanghe （Yellow） River. The relatively high abundant kaolinite is likely derived from the Changjiang （Yangtze） River via the Taiwan Warm Current. In contrast, large amounts of chlorite and high chlorite/kaolinite ratios occur in the northwestern area, reflecting the transportation by the Yellow Sea Coastal Current from the southern Yellow Sea. The discrimination diagrams clearly show that the sediments in the northwestern East China Sea are ultimately sourced from Chinese rivers, especially from the Huanghe River, whereas the sediment in the northeast part might come from the Jeju Island. The muddy sediments of the Changjiang River＇s submerged delta have much lower 87Sr/S6Sr ratios （0.716 2-0.718 0） than those of the Shandong Peninsular mud wedge （0.721 6-0.724 9）, which are supposed to be originated from the Huanghe River, suggesting the distribution pattern of 87Sr/86Sr ratios as a new tracer to discriminate the provenance of shelf sediments in the study area. The 87Sr/86Sr ratios of the outer-shelf muddy sediments ranged from 0.7169 to 0.7216 in a wide range and was between those of the Huanghe River and Changjiang River sediments, suggesting multiple sources of the sediment in the area.
基金supported by the Guangdong Major Project of Basic and Applied Basic Research(No.2019B030302013)the Strategic Priority Research Program of Chinese Academy of Sciences(No.XDB42000000)+1 种基金the National Natural Science Foundation of China(No.41773054)the National Key R&D Program of China(No.2016YFC0600408)。
文摘About 45%of tungsten,~20%of tin,and~9%of fluorite of known world reserves are associated with Late Mesozoic igneous rocks,Southeast(SE)China.Here we demonstrate that Fogang granite,the largest inland batholith,is mainly of A2-type that is commonly found in post-orogenic settings and experienced plate subduction induced metasomatism.In contrast,the Yajishan syenite and Nankunshan granite intruding the Fogang granite~20 Ma later are of A1-type formed in intraplate settings.We found that F-rich fluid fractionation,which could make the decline of Ga/Al ratio,total(Nb+Y+Ce+Zr)and Zr concentrations,Nb/Ta and Zr/Hf ratios,leads to chemical variations of a few Fogang granites changing from A2-type to highly fractionated or I-and S-type granitoids.Crystal and Frich fluid fractionations,as well as crustal contamination most likely derived from the Fogang granite,result in some Nankunshan granites developing from A1-type into A2-type.These late-or post-magmatic processes should be taken into account carefully when discriminating the petrogenetic types of igneous rocks,especially for the A2-type suites.Combining with the distribution of 180-140 Ma A1-and A2-type igneous rocks,rare metal deposits,and fluorite deposits in SE China,we highlight the significant role of slab-released F-rich fluids in formation of A-type suites and subsequent chemical differentiation and rare metal and fluorine mineralization.A model of flat-slab northeastward rollback is thus proposed,in which the subduction front reached somewhere near Fogang and then started to roll back at~165 Ma.The inland Jurassic granites of SE China represent a unique locality for formation of A-type suites and their associated mineralization.These granites are not anorogenic,but they are the result of slab rollback from a flat slab,founding of that slab at shallow levels,and metasomatism of by F-rich fluids related to slab heating by the asthenosphere.
基金supported by NSFC 91328204 to W.D.S.Strategic Priority Research Program(B)of the Chinese Academy of Sciences(XDB18020102)to W.D.S. and X.L.S.
文摘Cenozoic adakitic rocks in the Gangdese changed from barren continental melts to ore-forming slab melts at * 23 Ma. The distribution and chemical characteristics of the ore-forming adakites point to an association with the Ninetyeast Ridge. The subduction of the thick,rigid Ninetyeast Ridge changed the geometry and rheology of the eastern Tibetan Plateau lithosphere and asthenosphere, restrained the eastward escape of asthenospheric mantle as well as continental fragments, and promoted the uplift and building of the Tibetan Plateau, which consequently changed the tectonic and climatic regimes in eastern Asia.
文摘In an effort to assess the reliability of satellite altimeter systems, the authors conduct a comparative analysis of sea level data that were collected from the TOPEX/POSEIDON (T/P) altimeter and 10 tide gauges (TG) near the satellite passing ground tracks. The analysis is made using datasets collected from marginal sea regions surrounding the Korean Peninsula at T/P cycles of 2 to 230, which correspond to October 1992 to December 1998. Proper treatment of tidal errors is a very critical step in data processing because the study area has very strong tide. When the T/P data are processed, the procedures of Park and Gamberoni (1995) are adapted to reduce errors associated with the tide. When the T/P data are processed in this way, the alias periods of M2, S2, and K1 constituents are found to be 62.1, 58.7, and 173 days repectively. The compatibility of the T/P and TG datasets are examined at various filtering periods. The results indicate that the low-frequency signals of the T/P data can be interpreted more safely with longer filtering periods (such as up to the maximum selected value of 200 days). When RMS errors for the 200-day low-pass filter period are compared with all 10 tidal stations, the values span the range of 2.8 to 6.7 cm. The results of a correlation analysis for this filtering period also show a strong agreement between the T/P and TG datasets across all stations investigated (e.g.,p- values consistently less than 0.001). Hence according to the analysis, the conclusion is made that the analysis of surface sea level using satellite altimeter data can be made safely with reasonably extended filtering periods such as 200 days.
基金the Korea Meteorological Administration(KMA) Research and Development Program under Grant CATER 2006- 4205 and by BK21 program.Partial support for M.Kimoto was given by the Innovative Program of Climate Change for the 21st Century of the Japanese Ministry of Education, Culture,Sports,Science and Technology.
文摘Decadal changes in the subseasonal evolution and the phase-locked climatological intraseasonal fluctuation of summertime rainfall over the Korean Peninsula before and after the mid-1990s are investigated.The activity and the migration speed of the monsoon rain band over the East Asian region are altered in the recent decade,resulting in the drier conditions in late spring and the earlier onset of Changma.In early August when a climatological monsoon break was clear in the earlier decade,the precipitation has increased dramatically with a meridional coherency.The response to the enhanced convection over the South China Sea and southeastern China provides a favorable condition for more precipitation in early August through the changes in moisture transport and tropical cyclone passage.
基金Supported by the National Natural Science Foundation of China(Nos.41773009,41873002)the Stake Key Laboratory of Geological Processes and Mineral Resources(No.GPMR201708)+2 种基金the National Science Foundation for Post-doctoral Scientists of China(No.2018M640660)the Taishan Scholar Program of Shandong(No.TS201712075)the AoShan Talents Cultivation Program Supported by Qingdao National Laboratory for Marine Science and Technology(No.2017ASTCP-OS07)。
文摘A number of high-temperature processes(e.g.,melt-rock reactions,metasomatism,partial melting)can produce signifi cant Ca isotopic fractionation and heterogeneity in the mantle,but the mechanism for such fractionation remains obscure.To investigate the eff ect of mantle partial melting on Ca isotopic fractionation,we reported high-precision Ca isotopic compositions of depleted mid-ocean ridge basalts(MORBs)from the East Pacifi c Rise and Ecuador Rift in the northeastern Pacifi c.Theδ44/40 Ca of these MORB samples exhibit a narrow variation from 0.84‰to 0.88‰with an average of 0.85‰±0.03‰,which are similar to those of reported MORBs(0.83‰±0.11‰)and back-arc basin basalts(BABBs,0.80‰±0.08‰)in literature,but are lower than the estimate value for the bulk silicate Earth(BSE,0.94‰±0.05‰).The lowδ44/40 Ca signatures of MORB samples in this study cannot be caused by fractional crystallization,since intermediate-mafi c diff erentiation has been demonstrated having only limited eff ects on Ca isotopic fractionation.Instead,the off set ofδ44/40 Ca between MORBs and the BSE is most likely produced by mantle partial melting.During this process,the light Ca isotopes are preferentially transferred to the melt,while the heavy ones tend to stay in the residue,which is consistent with the fact thatδ44/40 Ca of melt-depleted peridotites increases with partial melting in literature.The behavior of Ca isotopes during mantle partial melting is closely related to the inter-mineral(Cpx and Opx)Ca isotopic fractionation and melting mineral modes.Mantle partial melting is one of the common processes that can induce lowerδ44/40 Ca values in basalts and Ca isotopic heterogeneity in Earth’s mantle.
基金Joint Seismological Sceince Foundation of China(305007).
文摘The 1975 Haicheng Ms7.3 earthquake affected whole Korean Peninsula and even Kyushu, Japan. In this paper isoseismal map of this earthquake was drawn for these areas by sorting out and analyzing data systematically collected, furthermore, the characteristics of the earthquake damage were discussed. In the northern Korean Peninsula, the intensity is V in great majority of this area except local area with intensity VI, and the damage is basically in accordance with typical characteristics of corresponding intensity grade. In the southern Korean Peninsula, the intensity is IV in large part of the area, however, in some big cities such as Seoul etc., not only high buildings shook strongly, but also some people appeared perceptions such as feeling dizzy and so on, and electrical service was interrupted on one or two districts because of transformer tripping. These phenomena could be caused by the effect of long-period wave generated from a large earthquake on far-field.
基金The Ministry of Land, Transport and Maritime Affairs of Korean Govenment as part of the EAST-I (East Asian Seas Time-series,East/Japan Sea) and OCCAPA (Ocean Chimate Change-Analyses, Projections and Adaptation), through KIOST Project under contract No. PE98742as part of the Development of Technology for CO2 Marine Geological Storage project under contract No. PMS246B
文摘Subinertial fluctuation of a strong northward deep current, which is referred to the Dokdo Abyssal Current （DAC） by Chang et al. （2009）, is investigated from current records for about 16.5 and 8.0 months in the Ulle- ung Interplain Gap of the East/lapan Sea. The current below 300 m is bottom-intensified and has nearly depth-independent flow. Near bottom, the spectral peaks of the current were found near 10, 20, and 60 d. The DAC variability near 10 d and 20 d is reasonably consistent with the linear theory of topographic Rossby waves （TRWs） in the following aspects： （1） The motion is columnar and bottom-intensified; （2） the theo- retical cutoff frequency is similar to the observation; （3） The observation-based angles of the wavenumber vector are in good agreement with the theoretical ones. The wavelengths of the TRWs with periods of near 10 d and 20 d near Dokdo are significantly shorter than those with similar timescales in the open oceans （100-250 km）. It is primarily due to the weak stratification below 300 m in the East Sea. The deep cur- rent fluctuations with periods of near 10 d and 20 d were accompanied by warm events in the upper layer resulting from eddying processes and/or meandering of the Tsushima Warm Current.
基金supported by the DREAM project of MOST China 2016YFC0600408NSFC 91328204,41421062China Geological Survey (12120114015801)
文摘South China is famous for the extensive magmatism and polymetallic mineralization that took place there in the Mesozoic. Shilu is a large porphyry–skarn Cu–Mo deposit in the Yangchun Basin, South China. The lithology of the Shilu intrusion is granodiorite and quartz diorite, both of which are high-K calc-alkaline series, with high Sr([400 ppm) content along with low Y and Yb contents. Most of the samples have characteristics of adakite except for a few samples that have slightly higher Y and Yb contents, which may be plausibly explained by crustal contamination. Laser Ablation Inductively Coupled Plasma Mass Spectrometry zircon U–Pb dating revealed ages between 106.6 ± 1.3 and 103.9 ± 0.5 Ma, with multiple magmatic pulses. Molybdenite Re–Os isochron age of 102.2 ± 2.9 Ma(MSWD = 9.4) was determined, which is identical to the youngest zircon U–Pb age(103.9 ± 0.5 Ma) within error.The Shilu intrusion has high oxygen fugacity as indicated by high zircon Ce^(4+)/Ce^(3+) and Eu_N/Eu_N* ratios. Considering the geochemical characteristics(high Sr, and low Y and Yb contents), high oxygen fugacity, and copper mineralization of the Shilu intrusion, it was most likely formed by partial melting of a subducted young oceanic slab. Whole-rock Sr–Nd isotope-, zircon Hf isotope-, and whole-rock trace element analyses show that Shilu adakitic magmas may have interacted with type II enriched mantle and/or crustal materials during ascent. South China was affected by the Pacific tectonic regime to the east and the Neo-Tethys tectonic regime to the south in the Cretaceous. Based on the Pacific Plate drifting and rotation history, it is hard to explain how the Pacific Plate would have subducted and melted, forming adakitic rocks in the Shilu region. Considering the tectonic history of Southeast Asia and the South China Sea, the Neo-Tethys trench should have been much closer to the South China Block in the Cretaceous, and thus have had a greater impact on the South China Block. Based on the subduction direction, time of subduction,and distance between the Neo-Tethys subduction zone and the Shilu deposit, subduction of the Neo-Tethys ridge is the best mechanism for explaining the Shilu adakitic rocks and Cu–Mo mineralization.
基金financially supported by the DREAM project of MOST,China(Grant No.2016YFC0600408)the Strategic Priority Research Program(B)of Chinese Academy of Sciences(Grant No.XDB18000000)the Program of the National Mineral Rock and Fossil Specimens Resource Center from MOST,China。
文摘A series of coesite,coexisting with or without a liquid phase,was synthesized in the nominal system SiO2-H2O at800-1450℃and 5 GPa.Micro-Raman spectroscopy was used to identity the crystalline phase,electron microprobe and LA-ICP-MS were employed to quantity some major and trace elements,and unpolarized FTIR spectroscopy was applied to probe the different types of hydrogen defects,explore water-incorporation mechanisms and quantify water contents.Trace amounts of A1 and B were detected in the coesite.Combining our results with the results in the literatures,we have found no positive correlation between the Al contents and the"Al"-based hydrogen concentrations,suggesting that previously proposed hydrogen-incorporation mechanism H^++Al^3+■Si^4+does not function in coesite.In contrast,we have confirmed the positive correlation between the B contents and the B-based hydrogen concentrations.The hydrogen-incorporation mechanism H^++B3^+■Si^4+readily takes place in coesite at different P-T conditions,and significantly increases the water content at both liquid-saturated and liquid-undersaturated conditions.For the SiO2-H2O system,we have found that type-Ⅰhydrogarnet substitution plays a dictating role in incorporating water into coesite at liquid-saturated condition,type-II hydrogarnet substitution contributes significantly at nearly dry condition,and both operate at conditions in between.The water solubility of coesite,as dictated by the type-Ⅰhydrogarnet substitution,positively correlates with both P and T,cH2O=-105(30)+5.2(32)×P+0.112(26)×T,with cH2O in wt ppm,P in GPa and T in℃.Due to its low water solubility and small fraction in subducted slabs,coesite may contribute insignificantly to the vertical water transport in subduction zones.Furthermore,the water solubility of any coesite in exhuming ultra-high pressure metamorphic rocks should be virtually zero as coesite becomes metastable.With an adequately fast waterdiffusion rate,this metastable coesite should be completely dry,which may have been the key factor to the partial preservation of most natural Coe.As a byproduct,a new IR experimental protocol for accurate water determination in optically anisotropic nominally anhydrous minerals has been found.Aided with the empirical method of Paterson(1982)it employs multiple unpolarized IR spectra,collected from randomly-orientated mineral grains,to approximate both total integrated absorbance and total integrated molar absorption coefficient.Its success relies on a high-level orientation randomness in the IR analyses.
文摘The plate tectonics theory is a milestone in solid Earth sciences.However,50 years after the theory has been proposed,the driving force behind plate drifts is still controversial(Sun 2016).Slab pull has been accepted as the dominant driving force of plate tectonics for a long time(Forsyth and Uyeda 1975).A major challenge of this model is how plate subduction was initiated in the first place(Arculus et al.2015,2019;Li et al.2019;Niu 2016;Niu et al.2003;O'Connor et al.2015;Sun 2016,2017;Zhou et al.2018).
基金co-financed by the European Regional Development Fund and the Republic of Cyprus through the Research and Innovation Foundation with grant number INTEGRATED/0918/0046(OS-Aqua).
文摘Global demand for seafood is constantly increasing,driven by population growth and rising per capita con-sumption.While wild-capture fisheries are facing limitations in meeting this demand,the expansion of aqua-culture emerges as the only solution.This paper investigates the potential for increasing the aquaculture production in the Republic of Cyprus by transitioning towards offshore aquaculture farms.The model developed provides a valuable roadmap for offshore transitions in Mediterranean near-coast areas.The study includes a detailed economic analysis coupled with sensitivity analysis to assess the feasibility of this transition considering various expansion scenarios.The results provide valuable insights into the viability and implications of this process,highlighting economic and operational issues.
基金supported by the National Key R&D Program of China (Grant Nos. 2016YFC0600204 & 2016YFC0600408)the National Natural Science Foundation of China (Grant Nos. 41421062 & 41372005)
文摘Granitic continental crust distinguishes the Earth from other planets in the Solar System. Consequently, for understanding terrestrial continent development, it is of great significance to investigate the formation and evolution of granite.Crystal fractionation is one of principal magma evolution mechanisms. Nevertheless, it is controversial whether crystal fractionation can effectively proceed in felsic magma systems because of the high viscosity and non-Newtonian behavior associated with granitic magmas. In this paper, we focus on the physical processes and evaluate the role of crystal fractionation in the evolution of granitic magmas during non-transport processes, i.e., in magma chambers and after emplacement. Based on physical calculations and analyses, we suggest that general mineral particles can settle only at tiny speed(~10^(-9)–10^(-7) m s^(-1))in a granitic magma body due to high viscosity of the magma; however, the cumulating can be interrupted with convection in magma chambers, and the components of magma chambers will tend to be homogeneous. Magma convection ceases once the magma chamber develops into a mush(crystallinity, F>~40–50%). The interstitial melts can be extracted by hindered settling and compaction, accumulating gradually and forming a highly silicic melt layer. The high silica melts can further evolve into high-silica granite or high-silica rhyolite. At various crystallinities, multiple rejuvenation of the mush and the following magma intrusion may generate a granite complex with various components. While one special type of granites, represented by the South China lithium-and fluoride-rich granite, has lower viscosity and solidus relative to general granitic magmas, and may form vertical zonation in mineral-assemblage and composition through crystal fractionation. Similar fabrics in general intrusions that show various components on small lengthscales are not the result of gravitational settling. Rather, the flowage differentiation may play a key role. In general, granitic magma can undergo effective crystal fractionation; high-silica granite and volcanics with highly fractionated characteristics may be the products of crystal fractionation of felsic magmas, and many granitoids may be cumulates.
基金supported by National Research Foundation of Korea (NRF) funded by the Korea government (MEST) (Grant No.2010-0029119)
文摘High-precision(±0.1 ppm) and high-frequency(hourly averaged) in situ measurements of atmospheric carbon dioxide(CO2) were made for the first time from August 2005 to July 2007 at Yanbian,China using a non-dispersive Infrared(NDIR) analyzer with National Oceanic and Atmospheric Administration/Earth System Research Laboratory(NOAA/ESRL) standards.The results of these measurements are presented in this paper and are used to investigate the regional representativeness of regional background data at Yanbian and determine the CO2 emission source regions in Northeast Asia.The phase of the monthly variations at Yanbian reflects the special regional characteristics,which were overall in excellent agreement with other observatories in the middle-to-high latitudes in the Northern Hemisphere.Applying a hybrid receptor model to the regional emission source events in cold period(November-April),we estimated the distribution of the major CO2 emissions in the northeast Asia.The results indicated that the strongest potential emission areas contributing to Yanbian are the Beijing & Tianjin metropolitan areas,southwestern part of Shandong Province including Jinan,and Vladivostok.The results of this study reveal the usefulness of in situ CO2 measurements at Yanbian in establishing the scientific foundation for monitoring the large CO2 emission areas in northern China and Russia.Continued monitoring of CO2 at Yanbian within a regional network should provide significant contributions to both understanding the global/regional carbon cycle and constraining "top-down" emissions in Northeast Asia.
文摘Wet deposition scavenges particles and particle-associated bacteria from the air column, but the impact of raindrops on various surfaces on Earth causes emission of surface-associated bacteria into the air column. Thus, after rainfall, these two mechanisms are expected to cause changes in airborne bacterial community composition （BCC）. In this study, aerosol samples were collected at a suburban site in Seoul, Korea before and after three heavy rainfall events in April, May, and July 2011. BCC was investigated by pyrosequencing the 16S rRNA gene in aerosol samples. Interestingly, the relative abundance of non-spore forming Actinobacteria operational taxonomic units （OTUs） was always higher in post-rain aerosol samples. In particular, the absolute and relative abundances of airborne Propionibacteriaceae always increased after rainfall, whereas those of airborne Firmicutes, including Carnobacteriaceae and Clostridiales, consistently decreased. Marine bacterial sequences, which were temporally important in aerosol samples, also decreased after rainfall events. Further, increases in pathogen-like sequences were often observed in post-rain air samples. Rainfall events seemed to affect airborne BCCs by the combined action of the two mechanisms, with potentially adverse effects on human and plant health.
基金supported by the Greek General Secretariat of Research and Technology through ESPA-KRIPIS Project: "Development of an integrated management framework of river basins and associated coastal and marine zone"
文摘This study reports on the first investigation into the potential of luminescence dating to establish a chronological framework for the depositional sequences of the Sperchios delta plain, central Greece. A series of three borehole cores(20 m deep) and two shallow cores(4 m deep), from across the delta plain, were extracted, and samples were collected for luminescence dating. The luminescence ages of sand-sized quartz grains were obtained from small aliquots of quartz, using the Single-Aliquot Regenerative-dose(SAR) protocol.The equivalent dose determination included a series of tests and the selection of the Minimum Age Model(MAM) as the most appropriate statistical model. This made it possible to confirm the applicability of quartz Optically Stimulated Luminescence(OSL) dating to establish absolute chronology for deltaic sediments from the Sperchios delta plain.Testing age results of the five cores showed that the deltaic sediments were deposited during the Holocene.A relatively rapid deposition is implied for the top14 m possibly as a result of the deceleration in the rate of the sea-level rise and the transition to terrestrial conditions, while on the deeper parts, the reduced sedimentation rate may indicate a lagoonal or coastal environment.
文摘In recent days,discrimination diagrams have been widely used for tracing the tectonic settings and origins of basalts from orogenic belts.However,conventional discrimination diagrams are not accurate enough.Here,we reported six new discrimination diagrams obtained from the global database using data mining methods.For most individual diagrams,island arc basalt can be nearly 100%was identified,whereas ocean island basalt and midocean ridge basalt can be discriminated from each other with less than 10%of overlap,under a confidence coefficient of 85%.Using the six new discrimination diagrams together,basalts of different origins can be efficiently identified.
基金supported by the‘Development of Typhoon and Ocean Applications’project,funded by ETRI,which is a subproject of the‘Development of Geostationary Meteorological Satellite Ground Segment(NMSC-2019-01)’program funded by NMSC of KMAThis research was a part of the project titled“Construction of Ocean Research Station and their Application Studies”funded by the Ministry of Oceans and Fisheries in republic of Korea.
文摘Estimating horizontal winds in and around typhoons is important for improved monitoring and prediction of typhoons and mitigating their damages.Here,we present a new algorithm for estimating typhoon winds using multiple satellite observations and its application to Typhoon Soulik(2018).Four kinds of satellite remote sensing data,along with their relationship to typhoon intensity,derived statistically from hundreds of historical typhoon cases,were merged into the final product of typhoon wind(MT wind):(1)geostationarysatellite-based infrared images(IR wind),(2)passive microwave sounder(MW wind),(3)feature-tracked atmospheric motion vectors,and (4)scatterometer-based sea surface winds(SSWs).The algorithm was applied to two cases(A and B)of Typhoon Soulik and validated against SSWs independently retrieved from active microwave synthetic aperture radar(SAR)and microwave radiometer(AMSR2)images,and vertical profiles of wind speed derived from reanalyzed data and dropsonde observations.For Case A(open ocean),the algorithm estimated the realistic maximum wind,radius of maximum wind,and radius of 15 m/s,which could not be estimated using the reanalysis data,demonstrating reasonable and practical estimates.However,for Case B(when the typhoon rapidly weakened just before making landfall in the Korean Peninsula),the algorithm significantly overestimated the parameters,primarily due to the overestimation of typhoon intensity.Our study highlights that realistic typhoon winds can be monitored continuously in real-time using multiple satellite observations,particularly when typhoon intensity is reasonably well predicted,providing timely analysis results and products of operational importance.
基金This study was supported by Korea Meteorological Administration/National Meteorological Satellite Center and‘Long-term change of structure and function in marine ecosystems of Korea’and‘East Asian Seas Time series-I(EAST-I)’projects funded by the Ministry of Oceans and Fisheries,Korea.
文摘Sea surface temperature(SST)retrieved from Advanced Very High Resolution Radiometer(AVHRR)onboard National Oceanic and Atmospheric Administration(NOAA)polar orbiting environmental satellites were validated in the East/Japan Sea(EJS)using surface drifter measurements as ground truths from 2005 to 2010.Overall,the root-mean-square(rms)errors of multichannel SSTs(MCSSTs)and non-linear SSTs(NLSSTs)using global SST coefficients were approximately 0.85℃ and 0.80℃,respectively.An analysis of the SST errors(satellite-drifter)revealed a dependence on the amount of atmospheric moisture.In addition,satellite-derived SSTs tended to be related to wind speeds,particularly during the night.The SST errors also demonstrated diurnal variations with relatively higher rms from 0.80℃ to 1.00℃ during the night than the day,with a small rms of about 0.50℃.Bias also exhibited reasonable diurnal differences,showing small biases during the daytime.Although a satellite zenith angle has been considered in the global SST coefficients,its effect on the SST errors still remained in case of the EJS.Given the diverse use of SST data,the continuous validation and understanding of the characteristic errors of satellite SSTs should be conducted based on extensive in-situ temperature measurements in the global ocean as well as local seas.
