Trace Metal Solid State Speciation in Aerosols of the Northern Levantine Basin,East Mediterranean

An established three stage sequential leach scheme was applied to a series of selected high volume aerosol samples (n = 35) collected from the Turkish Eastern Mediterranean coastline (Erdemli). Samples were selected according to their air mass back trajectory history to reflect the contrasting mixtures of aerosol material present in the Eastern Mediterranean marine aerosol. Two populations were adopted, those samples which were classed as “anthropogenic” and those which were “Saharan” dominated aerosol populations. Applying the three stage leach it was possible to define the proportion for each of the considered metals (Al, Fe, Cu, Pb, Cd, Zn and Mn) present in the (a) “exchangeable” (b) “carbonate / oxide” and (c) “refractory” phases, representing novel solid state aerosol speciation data for this marine system. Clear trends were established, conforming with data from previous studies with mainly crustal derived metals (Al and Fe) being present in the refractory phases (Al > 88%; Fe > 84%) and those influenced by anthropogenic sources being dominating in the exchangeable phase, although for these metals the variability was comparatively high (12–64%; 19–85%; 40–100% for Zn, Pb and Cd, respectively). For the majority, greater exchangeable fractions were present the lower the crustal source contribution to the aerosol population, whereas the “refractory” fraction exhibited contrasting behaviour. This was illustrated by the novel application of the mixing diagram, presenting each of the three speciation stages against the corresponding percent anthropogenic contribution to each collected sample. Zn, Pb and Cd all illustrated progressive decrease in the percent exchangeable with increasing crustal contribution to the aerosol population. The percent exchangeable was discussed in terms of its use to represent the upper limit of the bioavailable fraction of metal associated with the aerosol, post deposition. The mixing diagram approach enabled the prediction of the residual fractions for Cd, Pb and Zn (41 ± 4%; 62 ± 4% and 82 ± 5%, respectively,) in Saharan end-member material.     

Evolution Features of Depositional and Tectonic Setting from Late Paleozoic to Meso-Cenozoic in the Yong' an Basin

永安盆地发育在前泥盆纪基底之上,位于华夏块体南缘,沿NE向政和—大埔断裂带展布.利用层序地层学方法,辅之以野外调查,研究了永安盆地的地层序列和岩石组合:①对晚古生代至早三叠世地层格架及柱状剖面的分析表明,伴随海平面的升降,海相沉积序列具有阶段性,不同沉积相在盆地东、中、西区段分布不均,盆地沉积沉降中心大致位于龙岩和梅县地区;②对横贯盆区的地质剖面及盆内辅助剖面的研究表明,中—新生代,盆内以断块作用为主,改造了晚古生代地层,代之以断褶复合地层;③有机碳质层为盆地的海陆变迁作了时域界定,并且其赋存部位和形态也在空间上表征了盆地构造演化的力学机制.通过分析构造事件、古地理及物源区、深部构造、边界构造等盆地要素,研究了盆地的沉积构造环境演化及其应力机制,结果表明:①晚古生代,海进海退的快慢受控于不同时期构造事件的强弱变化,由此产生的沿岸隆起区的剥蚀以及拉张背景的山体风化剥蚀为盆地提供了物源,存在北、南两个物源区;中—新生代,盆地总体为火山活动背景下的山前及河湖相沉积环境.②盆地具有隆起—伸展构造发育的特点,主要经历了华力西期海陆交互相巨厚沉积阶段,印支期稳定的台地向活动大陆边缘转变阶段并伴随挤压隆升,以及印支期后中—新生代由挤压向拉张机制转换的构造改造阶段.以上认识为中国东南部盆地的薄弱基础研究提供了新的基础参考信息.     

华北及其邻区块体转动模式和动力来源

块体的转动是地壳中重要的构造运动形式。根据地质、地球物理和地震活动性等资料，可将华北及其邻区划分为３个亚板块，华北亚板块可进一步细分为多个级块体，这些不同级别的块体或多或少都显示出一定的刚体特性。根据地质构造、地震和古地磁测量等资料，详细地论细地论述了不同级块体的转动问题，即华北及其邻区的黑龙江、华北和华南等３个近东西向亚板块自老第三纪以来相对于新疆地区顺时针转动了１．６°～３．５°；华北亚板块内     

后疫情时代全球石油供需格局研究

2017年以来,全球石油消费持续疲软,消费增速呈逐渐下降的趋势,新冠肺炎疫情对石油需求的打击更是"雪上加霜".本文回顾了疫情发生以来国际原油价格及大型油气公司股票价格的走势,探讨了疫情对全球石油需求和供应市场的影响,研判了短期及中长期全球石油供需格局,得出了三点结论:(1)疫情对全球石油需求产生重大冲击,预计2020年...     

江西九江红土生物标志化合物的分布特征及其古气候环境意义

为了探求江西九江红土地层中所记录的古气候环境信息,论文在对江西九江红土剖面的野外地貌、岩性和相关沉积环境调查分析基础上,利用气相色谱-质谱联用仪对正构烷烃、一元正脂肪酸等生物标志化合物进行了研究,着重分析了正构烷烃和一元正脂肪酸的来源及其碳数分布特征。结果显示:江西九江红土剖面上部均质红土中正构烷烃的CPI、∑C_(21)~–/∑C_(22)~+及一元正脂肪酸的CPI_L值均大于其下部的网纹红土,且波动较为明显,表明网纹红土的形成气候比其上的均质红土形成时期气候暖湿,反映了中更新世中期(600～300kaBP)的极端暖湿期;正构烷烃的∑C_(21)~–/∑C_(22)~+、(C_(15)+C_(17)+C_(19))/(C_(27)+C_(29)+C_(31))、(C_(16)+C_(17)+C_(18))/(C_(29)+C_(31)+C_(33))、C_(17)/C_(31)在剖面上表现出一致的旋回性变化,反应了江西九江中更新世以来气候的冷暖旋回变化。结果表明红土地层中的生物标志化合物具有很好的古气候环境意义。     

方解石负载羟基磷灰石复合材料去除水中铀离子的PRB活性介质研究

铀污染地下水分布于世界多国,其危害备受关注。本文基于溶胶-凝胶法制备方解石负载羟基磷灰石复合材料(CLHC),通过静态与动态对比试验,探讨了PRB活性介质对水中铀离子的吸附机理和去除效果。试验结果表明,制备的CLHC表面被羟基磷灰石覆盖,对铀离子具有较强的吸附能力。当U的初浓度为5.0 mg/L、试验周期为2 h、溶液pH值为4、CLHC用量为0.5 g/L时,CLHC可以吸附水中所有的铀离子。CLHC对铀离子的吸附过程可以用Langmuir等温吸附模型、粒子内扩散吸附动力学模型和准二级吸附动力学模型较好地进行描述。石英砂负载羟基磷灰石与CLHC相比,后者具有更强的吸附能力,而且具有更长的使用寿命。CLHC在吸附铀的过程中没有价态变化,其对铀离子的吸附主要为离子交换的化学吸附。本研究的成果可为可渗透反应墙被应用于铀污染地下水修复提供试验依据。     

Cultivated land change in the Belt and Road Initiative region

The Belt and Road Initiative (BRI)–a development strategy proposed by China – provides unprecedented opportunities for multi-dimensional communication and cooperation across Asia, Africa and Europe. In this study, we analyse the spatio-temporal changes in cultivated land in the BRI countries (64 in total) to better understand the land use status of China along with its periphery for targeting specific collaboration. We apply FAO statistics and GlobeLand30 (the world’s finest land cover data at a 30-m resolution), and develop three indicator groups (namely quantity, conversion, and utilization degree) for the analysis. The results show that cultivated land area in the BRI region increased 3.73×10⁴ km² between 2000 and 2010. The increased cultivated land was mainly found in Central and Eastern Europe and Southeast Asia, while the decreased cultivated land was mostly concentrated in China. Russia ranks first with an increase of 1.59×10⁴ km² cultivated land area, followed by Hungary (0.66×10⁴ km²) and India (0.57×104 km2). China decreased 1.95×10⁴ km² cultivated land area, followed by Bangladesh (–0.22×10⁴ km²) and Thailand (–0.22×10⁴ km²). Cultivated land was mainly transferred to/from forest, grassland, artificial surfaces and bare land, and transfer types in different regions have different characteristics: while large amount of cultivated land in China was converted to artificial surfaces, considerable forest was converted to cultivated land in Southeast Asia. The increase of multi-cropping index dominated the region except the Central and Eastern Europe, while the increase of fragmentation index was prevailing in the region except for a few South Asian countries. Our results indicate that the negative consequence of cultivated land loss in China might be underestimated by the domestic- focused studies, as none of its close neighbours experienced such obvious cultivated land losses. Nevertheless, the increased cultivated land area in Southeast Asia and the extensive cultivated land use in Ukraine and Russia imply that the regional food production would be greatly improved if China’ “Go Out policy” would help those countries to intensify their cultivated land use.     

Ecological compensation for desertification control: A review

Desertification control is a crucial way to enhancing the ecological conditions of arid and semi-arid regions, and maintaining sustainable development globally. Designing and improving an ecological compensation mechanism for desertification control has great significance related to achieving balance amongst the needs of different economic subjects and the assurance of a sustained and stable supply of desert ecosystem services. In this paper, (1) the theoretical bases of ecological compensation for desertification control were re-analyzed; (2) the research status and challenges of three important topics related to ecological compensation for desertification control were systemically discussed, including compensation standards, ecosystem service supply-consumption process and multi-scale effects, and resource- environment basis and policy orientation; (3) a research framework of ecological compensation for desertification control based on the process of desert ecosystem service supply–flow–consumption was proposed; (4) and finally, seven priority research issues were discussed, which aimed to support ecological compensation policy-making and ecological engineering implementation for desertification control.     

Degrading river network due to urbanization in Yangtze River Delta

Evolution of river systems under the background of human activities has been a heated topic among geographers and hydrologists. Spatial and temporal variations of river systems during the 1960s–2010s in the Yangtze River Delta (YRD) were investigated based on streams derived from the topographic maps in the 1960s, 1980s and 2010s. A list of indices, drainage density (Dd), water surface ratio (WSR), ratio of area to length of main streams (R), evolution coefficient of tributaries (K) and box dimension (D), were classified into three types (quantitative, structural, and complex indices) and used to quantify the variations of stream structure. Results showed that: (1) quantitative indices (Dd, WSR) presented decreasing trend in the past 50 years, and Dd in Wuchengxiyu, Hangjiahu and Yindongnan have decreased most, about 20%. Structurally, the Qinhuai River basin was characterized by significant upward R, and K value in Hangjiahu went down dramatically by 46.8% during the 1960s–2010s. Decreasing tendency in D was found dominating across the YRD, and decreasing magnitude in Wuchengxiyu and Hangjiahu peaks for 7.8% and 6.5%, respectively in the YRD. (2) Urbanization affected the spatial pattern of river system, and areas with high level of urbanization exhibited least Dd (2.18 km/km²), WSR (6.52%), K (2.64) and D (1.42), compared to moderate and low levels of urbanization. (3) Urbanization also affected the evolution of stream system. In the past 50 years, areas with high level of urbanization showed compelling decreasing tendency in quantitative (27.2% and 19.3%) and complex indices (4.9%) and trend of enlarging of main rivers (4.5% and 7.9% in periods of the 1960s–1980s and the 1980s–2010s). In the recent 30 years, areas with low level of urbanization were detected with significant downward trend in Dd and K. (4) Expanding of urban land, construction of hydraulic engineering and irrigation and water conservancy activities were the main means which degraded the river system in the YRD.     

大尺度水循环模拟系统不确定性研究进展(英文)

The regional hydrological system is extremely complex because it is affected not only by physical factors but also by human dimensions.And the hydrological models play a very important role in simulating the complex system.However,there have not been effective methods for the model reliability and uncertainty analysis due to its complexity and difficulty.The uncertainties in hydrological modeling come from four important aspects:uncertainties in input data and parameters,uncertainties in model structure,uncertainties in analysis method and the initial and boundary conditions.This paper systematically reviewed the recent advances in the study of the uncertainty analysis approaches in the large-scale complex hydrological model on the basis of uncertainty sources.Also,the shortcomings and insufficiencies in the uncertainty analysis for complex hydrological models are pointed out.And then a new uncertainty quantification platform PSUADE and its uncertainty quantification methods were introduced,which will be a powerful tool and platform for uncertainty analysis of large-scale complex hydrological models.Finally,some future perspectives on uncertainty quantification are put forward.