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Marine dispersion of Fukushima-derived radiocesium in the North Pacific and its implications

Science China Earth Sciences 2025年

作者： Tong ZHANG Xiaolin HOU Yukun FAN state key laboratory of Loess and quaternary geology Shaanxi Key Laboratory of Accelerator Mass Spectrometry Technology and Application Xi'an AMS Center Institute of Earth Environment Chinese Academy of Sciences University of Chinese Academy of Sciences Xi'an Institute for Innovative Earth Environment Research

A key scientific approach to addressing the environmental radiation risks from Fukushima nuclear contaminated water （FNCW） discharge into the ocean is understanding and predicting the marine dispersion of *** dispersion of radiocesium (CsF:134Cs,137Cs) from the Fukushima nuclear accident in the North Pacific and its marginal seas post-2011 was systematically summarized,focusing on pathways,vertical distribution changes,and transit *** research examined CsFdispersion through the Kuroshio Extension and denser central mode water （D-CMW） to the eastern North Pacific,as well as through subtropical mode water （STMW）,lighter central mode water （L-CMW）,and D-CMW to the subtropical western North Pacific,China Seas,and Sea of *** considered broader implications of CsFdispersion in light of ongoing FNCW *** this prolonged liquid discharge and Kuroshio Extension’s barrier effect,it is crucial to emphasize the role of CMW besides STMW in transporting FNCW to the subtropical western North Pacific and its marginal *** research should focus on the key mechanism and longitude range of CMW crossing the Kuroshio *** short-lived134Cs decays rapidly during the storage and dispersion of FNCW,long-lived135Cs and135Cs/137Cs ratios can serve as valuable tracers for detecting and quantifying ***,there is an urgent need for high-precision analysis of these key radionuclides and their characteristic *** promptly detect,assess,and respond to FNCW intrusion,continuous monitoring and identification of nuclear pollution sources in key ocean currents and straits are ***,interdisciplinary research integrating monitoring with marginal sea circulation dynamics and high-resolution numerical simulations should be a priority

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Spatiotemporal evolution of wildfire activity during the PaleoceneEocene Thermal Maximum in China

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Science China Earth Sciences 2025年

作者： Xueting WANG Zuoling CHEN Linlin CUI Xu WANG state key laboratory of Lithospheric and Environmental Coevolution Institute of Geology and Geophysics Chinese Academy of Sciences University of Chinese Academy of Sciences College of Earth and Planetary Sciences Institute of geology and Geophysics Chinese Academy of Sciences

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 CO2emissions from burning fossil *** 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 carbo

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The Impacts of Optical Properties on Radiative Forcing Due to Dust Aerosol

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Advances in atmospheric Sciences 2006年第3期23卷 431-441页

作者：王宏石广玉李书严李伟王标黄彦彬 state key laboratory of Severe Weather/Center for Numerical Prediction Research state key laboratory of atmospheric and quaternary geology Hainan Meteorology and Ecology Institute

There are large uncertainties in the quantitative assessment of radiative effects due to atmospheric dust aerosol. The optical properties contribute much to those uncertainties. The authors perform several sensitivity experiments to estimate the impacts of optical characteristics on regional radiative forcing in this paper. The experiments involve in refractive indices, single scattering aibedo, asymmetry factor and optical depth. An updated dataset of refractive indices representing East Asian dust and the one recommended by the World Meteorology Organization （WMO） are contrastively analyzed and used. A radiative transfer code for solar and thermal infrared radiation with detailed aerosol parameterization is employed. The strongest emphasis is on the refractive indices since other optical parameters strongly depend on it, and the authors found a strong sensitivity of radiative forcing on refractive indices. Studies show stronger scattering, weaker absorption and forward scattering of the East Asian dust particles at solar wavelengths, which leads to higher negative forcing, lower positive forcing and bigger net forcing at the top of the atmosphere （TOA） than that of the WMO dust model. It is also found that the TOA forcings resulting from these two dust models have opposite signs in certain regions, which implies the importance of accurate measurements of optical properties in the quantitative estimation of radiative forcing.

关键词： optical properties dust aerosol radiative forcing

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Carbon isotopic composition of modern soil and paleosol as a response to vegetation change on the Chinese Loess Plateau

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Science China Earth Sciences 2005年第1期48卷 93-99页

作者： LIU Weiguo NING Youfeng AN Zhisheng WU Zhenghai LU Huayu CAO Yunning state key laboratory of Loess and quaternary geology IEE Chinese Academy of Sciences Xi'an 710075 China State Key Laboratory of Loess and Quaternary Geology IEE Chinese Academy of Sciences Xi'an 710075 China State Key Laboratory of Loess and Quaternary Geology IEE Chinese Academy of Sciences Xi'an 710075 China Northwest Sci-Tech University of Agriculture and Forest Yangling 710000 China State Key Laboratory of Loess and Quaternary Geology IEE Chinese Academy of Sciences Xi'an 710075 China State Key Laboratory of Loess and Quaternary Geology IEE Chinese Academy of Sciences Xi'an 710075 China

The relationship between the carbon isotopic composition of paleosols and paleovegetation on the Loess Plateau is still unclear. One of the main reasons is that we are short of knowledge about the characteristics of the carbon isotopic composition of modern soil in this area. A preliminary investigation of the carbon isotopic compositions of the modern soil and the loess/paleosol sequence on the Loess Plateau shows that the carbon isotopic composition of modern soil is consistent with the distribution of modern plants on the Loess Plateau, where the ecosystem is dominated by a mixture of C4 and C3 plants. Comparing theδ13C values of modern soil and loess-paleosol sequences from the Xunyi profile, we conclude that C3 plants dominated the landscape during loess sediment stages, while C4 plants expanded during paleosol stages.

关键词： modern soil, paleosol, carbon isotope, paleovegetation, Loess Plateau.

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Paleoclimatic significance of grain size of loess-palaeosol deposit in Chinese Loess Plateau

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Science China Earth Sciences 1998年第6期41卷 626-631页

作者：鹿化煜安芷生 state key laboratory of Loess and quaternary geology Chinese Academy of Sciences Xi’an China

Particle size analysis for samples from three last glacial cycle loess-palaeosol profiles along a northwestsoutheast transection on the Chinese Loess Plateau has been carried out. The paleoclimatic significance of grain size indices has been obtained by analyzing the fraction content variations and their comparisons with global ice volume and solar radiation variations. The results show that (i) paleoclimatic significance of the grain size indices of loess-palaeosol deposit is different with grain size fraction content and sampling points in Chinese Loess Plateau; (ii) the sub-coarse grain fraction is a good proxy index of East Asia winter monsoon strength and therefore can be used to detect the global climate changes; (iii) the content of sub-fine and fine grain fractions is influenced by both the input of sub-coarse grain fraction and pedogenesis; (iv) the sub-coarse fraction exhibits a negative relationship with the sub-fine and fine fractlon.

关键词： paleoclimatic significance loess_palaeosol grain size Chinese Loess Plateau.

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Changes in grain-size and sedimentation rate of the Neogene Red Clay deposits along the Chinese Loess Plateau and implications for the palaeowind system

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Science China Earth Sciences 2005年第9期48卷 1452-1462页

作者： WEN Lingjuan LU Huayu QIANG Xiaoke state key laboratory of Loess and quaternary geology Institute of Earth Environment Chinese Academy of Sciences Xi'an 710075 China State Key Laboratory of Loess and Quaternary Geology Institute of Earth Environment Chinese Academy of Sciences Xi'an 710075 China State Key Laboratory of Loess and Quaternary Geology Institute of Earth Environment Chinese Academy of Sciences Xi'an 710075 China

The wind system responsible for transporting dust onto the Chinese Loess Plateau during the late Miocene and Pliocene is still unknown and recent investigations highlight many controversies. This report aims to investigate spatiotemporal changes in grain-size and sedi- mentation rate of the Neogene Red Clay deposits in north China and to explore palaeoclimatic changes during the late Miocene and Pliocene, in particular the palaeowind system that trans- ported dust. Samples were collected from eight Red Clay sections on the Loess Plateau. Meas- urement and analysis show that there is a clear southward decrease in the mean grain-size index and in the coarse particle fraction (>20 μm). At Jiaxian site on the northern Loess Plateau, the average mean grain-size is around 20 μm, while at Lantian site in the south, the mean is around 9 μm. The coarse particle fraction >20 μm makes up 24.4% and 5.6%, at the two sites respec- tively. This distinct diversity of grain-size in the aeolian Red Clay deposit between the north and south indicate that the palaeodust was transported mainly by northerly low-level winds. The grain-size variations in the Red Clay deposits can also be divided into three stages (the lower, the middle and the upper interval): grain-size of the lower stage is significantly coarser than that of the middle stage, but finer than that of the upper stage. As a consequence, the intensity of pa- laeowind and desiccation of the dust source region during the late Miocene and Pliocene can be divided into three stages: 6.2―5.4 Ma, 5.4―3.5 Ma and 3.5―2.6 Ma. Strength of the palaeowind during the middle stage (5.4―3.5 Ma) is weaker than that of the previous and subsequent stages and the intensity of palaeowind during the latest stage (3.5―2.6 Ma) is stronger than that of the early time (6.2―5.4 Ma). Variations in the sedimentation rate of the Red Clay deposit can also be divided into three stages: the earlier, the middle and the later interval. The sedimentation rate of

关键词： Red Clay deposit, grain size, atmospheric circulation, the late Miocene and the Pliocene, Chinese Loess Plateau.

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Distribution of branched glycerol dialkyl glycerol tetraethers in soils on the Northeastern Qinghai-Tibetan Plateau and possible production by nitrite-reducing bacteria

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Science China Earth Sciences 2016年第9期59卷 1834-1846页

作者： SUN ChiJun ZHANG ChuanLun LI Fu Yan WANG HuanYe LIU WeiGuo state key laboratory of Marine geology Tongji University Department of Earth and Planetary Sciences Northwestern University state key laboratory of Loess and quaternary geology Institute of Earth Environment Chinese Academy of Sciences

Branched glycerol dialkyl glycerol tetraethers （bGDGTs） are ubiquitous and abundant in soils, but their sources remain elusive. Recent studies demonstrate that the distributions of bGDGTs are sensitive to various environmental factors. In an effort to understand how and to what extent soil moisture （expressed as soil water content （SWC） or mean annual precipita- tion （MAP）, pH and temperature may impact the distribution of bGDGTs, and to shed more light on the biological sources of bGDGTs in cold and arid regions, we investigated the distribution of bGDGTs as well as bacterial 16S rRNA gene and func- tional genes involved in the N cycle （including amoA, nirS and nirK） in 41 surface soil samples from around Lake Qinghai and east of Qaidam Basin on the Northeastern Qinghai-Tibetan Plateau. We found that lower soil moisture reduced the fractional concentrations of cyclic bGDGTs and thus the cyclisation ratio of branched tetraethers （CBT） index correlated negatively with SWC and MAP, suggesting that soil moisture is an important factor controlling bGDGT distributions in soils in this add and semi-add region. Two subgroups of bGDGTs were assigned on the basis of cluster analysis, and bGDGT indices behaved dif- ferently in the two groups, hinting at different biosynthetic mechanisms for bGDGTs under different environmental conditions. Real time PCR results showed that nirS and nirK genes correlated significantly with the concentration of bGDGTs, suggesting that the nirS- or nirK-encoding bacteria involved in denitrification might potentially be an additional biological source for soil bGDGTs （besides Acidobacteria）. Moreover, our results also support the application of new indices based on 5-methyl bGDGTs and 6-methyl bGDGTs in reconstructing past temperature and pH variations in this region.

关键词： bGDGTs Soil water content CBT nirS- or nirK-encoding bacteria Real time PCR Cluster analysis

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Observational Characteristics of Cloud Radiative Effects over Three Arid Regions in the Northern Hemisphere

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Journal of Meteorological Research 2017年第4期31卷 654-664页

作者： Jiandong LI Tianhe WANG Ammara HABIB state key laboratory of Numerical Modeling for atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric PhysicsChinese Academy of Sciences state key laboratory of Loess and quaternary geology Institute of Earth EnvironmentChinese Academy of Sciences key laboratory for Semi-Arid Climate Change of the Ministry of Education College of Atmospheric SciencesLanzhou University

Cloud–radiation processes play an important role in regional energy budgets and surface temperature changes over arid regions. Cloud radiative effects（CREs） are used to quantitatively measure the aforementioned climatic role. This study investigates the characteristics of CREs and their temporal variations over three arid regions in central Asia（CA）, East Asia（EA）, and North America（NA）, based on recent satellite datasets. Our results show that the annual mean shortwave（SW） and net CREs（SWCRE and NCRE） over the three arid regions are weaker than those in the same latitudinal zone of the Northern Hemisphere. In most cold months（November–March）, the longwave（LW）CRE is stronger than the SWCRE over the three arid regions, leading to a positive NCRE and radiative warming in the regional atmosphere–land surface system. The cold-season mean NCRE at the top of the atmosphere（TOA） averaged over EA is 4.1 W m^-2, with a positive NCRE from November to March, and the intensity and duration of the positive NCRE is larger than that over CA and NA. The CREs over the arid regions of EA exhibit remarkable annual cycles due to the influence of the monsoon in the south. The TOA LWCRE over arid regions is closely related to the high-cloud fraction, and the SWCRE relates well to the total cloud fraction. In addition, the relationship between the SWCRE and the low-cloud fraction is good over NA because of the considerable occurrence of low cloud. Further results show that the interannual variation of TOA CREs is small over the arid regions of CA and EA, but their surface LWCREs show certain decreasing trends that correspond well to their decreasing total cloud fraction. It is suggested that combined studies of more observational cloud properties and meteorological elements are needed for indepth understanding of cloud–radiation processes over arid regions of the Northern Hemisphere.

关键词： arid region cloud fraction cloud radiative effects

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Chemical signature and fractionation of trace elements in fine particles from anthropogenic and natural sources

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Journal of Environmental Sciences 2022年第4期34卷 365-375页

作者： Rujin Huang Wei Yuan Ting Wang Wenjuan Cao Ying Wang Chunshui Lin Lu Yang Jie Guo Haiyan Ni Feng Wu state key laboratory of Loess and quaternary geology(SKLLQG) Center for Excellence in Quaternary Science and Global Changeand Key Laboratory of Aerosol Chemistry and PhysicsInstitute of Earth EnvironmentChinese Academy of SciencesXi’an 710061China

The health effects of trace metal elements in atmospheric fine particulate matter(PM_(2.5))are widely recognized,however,the emission factor profiles and chemical fractionation of metal elements in different sources were poorly *** this study,sixteen metal elements,including Cd,Pb,V,Zn,Ba,Sb,As,Fe,Sr,Cr,Rb,Co,Mn,Cu,Ni and Sn frombiomass burning,bituminite and anthracite combustion,as well as dust,were *** results showdifferent emission sourceswere associated with distinct emission profiles,holding important implications for source apportionment of ambient particulate ***,Fe was the dominant metal species(28-1922 mg/kg)for all samples,and was followed by different metals for different *** dust,Mn(39.9 mg/kg_(dust))had the second-highest emission factor,while for biomass burning,itwas Cr and Ba(7.5 and 7.4mg/kg_(biomass),respectively).For bituminous coal combustion,the emission factor of Zn and Ba was 6.2 and 6.0 mg/kg_(bituminous),respectively,while for anthracite combustion the corresponding emission factor was 5.6 and 4.3 mg/kg_(anthracite),***,chemical fractionation(i.e.,the exchangeable,reducible fraction,oxidizable,and residual fraction)and the bioavailability index(BI)values of the metal elements from different sources were further investigated to reveal the link between different emission sources and the potential health *** findings from this study hold important implications for source apportionment and sourcespecific particulate metal-associated health effects.

关键词： Metal elements Sources Emission profiles Chemical fractionation

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Ecophysiological responses of winter wheat seedling to aerosol wet deposition of Xi'an area, China

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Journal of Environmental Sciences 2010年第11期22卷 1786-1791页

作者： Yiping Chen state key laboratory of Loess and quaternary geology Institute of Earth Environment Chinese Academy of Sciences Xi'an 710075 China.

Aerosol leads to 30% reduction in solar radiation reaching the earth’s surface, and a similar reduction in crops yield for both wheat and rice. To determine the effect of aerosol wet deposition on crops, aerosol samples were collected in September, 2006 at Xi’an urban suburb （34 44 N, 109 49 E）, and wheat seedlings were treated with aerosol of different concentrations in laboratory conditions. Changes in physiological and biochemical parameters of wheat seedlings were measured. In comparison with the control, the activities of superoxide dismudase （SOD） and catalase （CAT） and the concentration malondialdehyde （MDA） and oxidized glutathione （GSSG） of wheat seedlings increased progressively with increasing concentrations of added aerosol, while the opposite trend was seen for the activities of nitric oxide synthase （NOS）, the concentrations of glutathione （GSH） and nitric oxide （NO）, and the ratio of GSH/GSSG. When the seedlings were treated with the aerosol of 1 and 2 mg/L, the coleoptile elongation, shoot elongation and biomass accumulation were increased, the effect at treatment of 2 mg/L was most significant. However, aerosol treatments with rates of 3 and 4 mg/L resulted in a decrease in coleoptile elongation, shoot elongation and biomass accumulation in seedlings, and significant effect was for the treatment of 4 mg/L. Hence, lower concentrations of aerosol wet deposition were in favor of crops growth, but its higher concentrations could result in deleterious effects for crops and decreased crops growth.

关键词： aerosol deposition environment pollution air pollution ecotoxicological testing aerosol risk assessment

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