CMIP5地球系统模式溶解氧模拟结果分析

本文基于常用的统计方法,通过与WOA09观测的海洋溶解氧浓度数据进行比较,定量地评估了9个CMIP5地球系统模式在历史排放试验中海洋溶解氧气候态特征的模拟能力。在海表,由于地球系统模式均能很好地模拟海表温度（SST）,模式模拟的海表溶解氧浓度分布与观测一致,模拟结果无论是全球平均浓度偏差还是均方根误差均接近0,空间相关系数与标准偏差接近1。在海洋中层以及深层这些重要水团所在的区域,各模式的模拟能力则差异较大,尤其在溶解氧低值区（OMZs）所在的500m到1000m,各模式均出现全球平均偏差、均方根误差的极大值以及空间相关系数的极小值。在海洋内部,模式偏差的原因比较复杂。经向翻转环流和颗粒有机碳通量均对模式的偏差有贡献。分析结果表明物理场偏差对溶解氧偏差的贡献较大。一些重要水团,比如北大西洋深水,南极底层水以及北太平洋中层水在极大程度上影响了溶解氧在这些海区的分布。需要指出的是,虽然在海洋内部各模式模拟的溶解氧浓度偏差较大,但是多模式平均结果却能表现出与观测较好的一致性。     

Anomalous hydrogen emissions from the San Andreas fault observed at the Cienega Winery,central California

We began continuous monitoring of H₂ concentration in soil along the San Andreas and Calaveras faults in central California in December 1980, using small H₂/O₂ fuel-cell sensors. Ten monitoring stations deployed to date have shown that anomalous H₂ emissions take place occasionally in addition to diurnal changes. Among the ten sites, the Cienega Winery site has produced data that are characterized by very small diurnal changes, a stable baseline, and remarkably distinct spike-like H₂ anomalies since its installation in July 1982. A major peak appeared on 1–10 November 1982, and another on 3 April 1983, and a medium peak on 1 November 1983. The occurrences of these peaks coincided with periods of very low seismicity within a radius of 50 km from the site. In order to methodically assess how these peaks are related to earthquakes, three H₂ degassing models were examined. A plausible correlational pattern was obtained by using a model that (1) adopts a hemicircular spreading pattern of H₂ along an incipient fracture plane from the hypocenter of an earthquake, (2) relies on the FeO–H₂O reaction for H₂ generation, and (3) relates the accumulated amount of H₂ to the mass of serpentinization of underlying ophiolitic rocks; the mass was tentatively assumed to be proportional to the seismic energy of the earthquake.     

Sectoral targets for developing countries: combining ‘common but differentiated re-sponsibilities’ with ‘meaningful participation’

Although a global cap-and-trade system is seen by many researchers as the most cost-efficient solution to reduce greenhouse gas (GHG) emissions, the governments of developing countries refuse to enter into such a system in the short term. Many scholars and stakeholders, including the European Commission, have thus proposed various types of commitments for developing countries that appear less stringent, such as sectoral approaches. A macroeconomic assessment of such a sectoral approach is provided for developing countries. Two policy scenarios in particular are assessed, in which developed countries continue with Kyoto-type absolute commitments, while developing countries adopt an emissions trading system limited to electricity generation and linked to developed countries' cap-and-trade systems. In the first scenario, CO₂ allowances are auctioned by the government, which distributes its revenues as a lump sum to households. In a second scenario, the auction revenues are used to reduce taxes on, or to give subsidies to, electricity generation. The quantitative analysis, conducted with a hybrid general equilibrium model, shows that such options provide almost as much emissions reduction as a global cap-and-trade system. Moreover, in the second sectoral scenario, GDP losses in developing countries are much lower than with a global cap-and-trade system, as is also the effect on the electricity price.     

胶东金矿集区硫和碳的循环与控矿作用

胶东金矿集区矿石中普遍含金属硫化物和碳酸盐矿物,某些矿床中还见有富含炭质的断裂破碎带.成矿溶液中含有大量的SO4^2-、HCO3^-、CO2和有机质等的含硫和含碳组分.矿石硫同位素组成明显富集重硫,结合胶东金矿主要成矿时期（早白垩世）特殊的地质背景、同期海水硫酸盐δ^34S平均值（约＋16‰）及现代海水沿NE-NNE向断裂倒灌情况,笔者认为,硫的主要来源与海水硫的大量补给有关.而根据碳、氧同位素组成特征分析,形成金矿床中方解石的物源有很大一部分来自前寒武系碳酸盐岩.浅表环境下成矿金属元素及硫、碳等物质在热液对流系统中的大规模循环是成矿的关键,SO4^2-与S2^-之间的临界转化是制约成矿金属元素活化-迁移-聚集的重要因素,而含碳组分（CO3^2-、HCO3^-、CO2和有机质）则有利于Au、Cu、Pb、Zn等元素的活化和迁移,含硫和含碳组分的循环及有关的物理化学反应之间有明显的关联性.     

The Converter Mechanism of Particle Acceleration and Its Applications to the Unidentified Egret Sources

We discuss the properties of gamma-ray radiation accompanying the acceleration of cosmic rays via the converter mechanism. The mechanism exploits multiple photon-induced conversions of high-energy particles from charged into neutral state (namely, protons to neutrons and electrons to photons) and back. Because a particle in the neutral state can freely cross the magnetic field lines, this allows to avoid both particle losses downstream and reduction in the energy gain factor, which normally takes place due to highly collimated distribution of accelerated particles. The converter mechanism efficiently operates in relativistic outflows under the conditions typical for Active Galactic Nuclei, Gamma-Ray Bursts, and microquasars, where it outperforms the standard diffusive shock acceleration. The accompanying radiation has a number of distinctive features, such as an increase of the maximum energy of synchrotron photons and peculiar radiation beam-pattern, whose opening angle is much wider at larger photon energies. This provides an opportunity to observe off-axis relativistic jets in GeV–TeV energy range. One of the implications is the possibility to explain high-latitude unidentified EGRET sources as off-axis but otherwise typical relativistic-jet sources, such as blazars.     

Multiple controls on the paleoenvironment of the Early Cambrian marine black shales in the Sichuan Basin,SW China: Geochemical and organic carbon isotopic evidence

In order to understand the paleoenvironment of the Early Cambrian black shale deposition in the western part of the Yangtze Block, geochemical and organic carbon isotopic studies have been performed on two wells that have drilled through the Qiongzhusi Formation in the central and southeastern parts of Sichuan Basin. It shows that the lowest part of the Qiongzhusi Formation has high TOC abundance, while the middle and upper parts display relative low TOC content. Redox-sensitive element (Mo) and trace elemental redox indices (e.g., Ni/Co, V/Cr, U/Th and V/(V + Ni)) suggest that the high-TOC layers were deposited under anoxic conditions, whereas the low-TOC layers under relatively dysoxic/oxic conditions. The relationship of the enrichment factors of Mo and U further shows a transition from suboxic low-TOC layers to euxinic high-TOC layers. On the basis of the Mo-TOC relationship, the Qiongzhusi Formation black shales were deposited in a basin under moderately restricted conditions. Organic carbon isotopes display temporal variations in the Qiongzhusi Formation, with a positive excursion of δ¹³C_org values in the lower part and a continuous positive shift in the middle and upper parts. All these geochemical and isotopic criteria indicate a paleoenvironmental change from bottom anoxic to middle and upper dysoxic/oxic conditions for the Qiongzhusi Formation black shales. The correlation of organic carbon isotopic data for the Lower Cambrian black shales in different regions of the Yangtze Block shows consistent positive excursion of δ¹³C_org values in the lower part for each section. This excursion can be ascribed to the widespread Early Cambrian transgression in the Yangtze Block, under which black shales were deposited.     

海洋纹层硅藻席古海洋学与生物地球化学研究进展

海洋大型硅藻的勃发及其在海底的纹层硅藻席沉积代表大规模的有机碳和生物硅输出通量,该生物堆积事件或过程对海洋酸化和全球变暖产生负反馈,因而在气候变化中的地位不容小觑。本文在融入作者研究成果的基础上总结了国内外关于海洋纹层硅藻席的研究现状,认为大型硅藻勃发不能直接和上涌活动相关联,在热带海区一般与成层化相关,在亚热带海区总体上与锋面作用相关。大型硅藻勃发时,表层水不一定贫养,也可以是富养的,也不总是需要借助浮力下沉到营养跃层吸收营养物,可直接吸收海洋表层中的营养物(如风尘溶解来源的硅酸)。大型硅藻通过高的初级生产力吸收大气中的CO_2,尔后在海洋深部降解形成的CO_2在海洋成层化条件下以巨大"呼吸CO_2库"得以封存,代表促使冰期大气pCO_2降低的一种重要机制。海洋纹层硅藻席的保存环境由多种因素制约,可以是氧化的也可以是亚氧化的,因而对用纹层沉积物来指示缺氧底层水条件应持谨慎态度。另外,提出了解释大型硅藻勃发和硅藻席形成机制的新模式"风尘触发硅藻席沉积",极大地促进了硅藻席沉积成因谜团的解决。最后,指出了目前海洋纹层硅藻席研究中存在的问题并阐述了未来可以开展的研究方向。     

福建省贝藻类养殖碳汇及其潜力评估

海水贝藻类养殖碳汇是海洋渔业碳汇的重要组成,开展其碳汇研究对服务我国实现碳中和目标有积极的作用.福建省的海水养殖规模和产量居于全国前列,对其海水贝藻类养殖碳汇及潜力评估有重要的意义.本研究分析了2015至2020年度《中国渔业统计年鉴》海水贝藻类养殖数据,估算了2014年至2019年全国及福建省海水贝藻类养殖碳汇强度,...     

渤海湾渔业碳汇分析与预测初探

为了解渤海湾近十年来渔业碳汇能力,本研究汇总了渤海湾地区2010-2020年海水养殖的品种和产量。通过建立不同养殖品种固碳能力评估体系,计算了不同养殖品种对渔业碳汇的贡献和渤海湾近十年海水养殖固碳总量。结果表明,2010-2020年渤海湾海水养殖以池塘养殖为主要养殖模式,年固碳量从2010年的5.79万吨增至2020年的11.04万吨,十年内共计固碳96.0万吨,平均碳转化比为12.5%,其中山东省贡献超过65%。该探索对建立“渔业碳汇”计算的指标体系、科学发展碳汇渔业、提升海洋碳汇生态价值具有一定的指导意义。