五台山大气CO2本底浓度及源汇特征

基于五台山站2017年1月~2020年12月的大气CO₂连续观测资料,采用平均移动过滤法（MAF）和后向轨迹分析方法,对五台山大气CO₂本底浓度及源汇特征进行研究.结果表明：五台山大气CO₂浓度受到区域或局地源汇的影响,筛分后的CO₂本底小时浓度振幅为44.9×10^-6,小于未经筛分的CO₂浓度振幅94.7×10^-6.2017~2020年CO₂本底浓度呈逐年上升趋势,但增幅放缓;抬升浓度占比有所下降,吸收浓度占比波动较小,表明人类活动对CO₂浓度的影响逐年减弱,而五台山周边地区陆地生态系统碳汇作用相对稳定.CO₂本底浓度夏季最低,秋冬季次之,春季最高;日变化夏季最明显,峰谷值分别出现在05：00和16：00,其他季节日振幅仅在0.7×10^-6~1.8×10^-6之间.与本底浓度相比,抬升浓度的差异值自10月至翌年3月明显增大,而吸收浓度的差异值在6~9月最显著,分别反映出人为活动排放源以及陆地生态系统吸收汇对CO₂本底浓度的影响.源汇浓度日变化均为单峰结构,抬升浓度白天高、夜间低,吸收浓度刚好相反.春、秋和冬季造成CO₂浓度明显抬升的地面风向主要为西南风,且随风速的增加CO₂浓度能够保持较高水平,而夏季主要为东北偏东风;春、夏季,2~4m/s的风速有利于进一步降低CO₂吸收浓度.后向轨迹分析表明,气团远距离输送对源汇浓度的影响除了取决于气团途径区域的CO₂排放情况,还与气团的空间垂直输送路径有关.     

The origin of stable halogenated compounds in volcanic gases

BACKGROUND: Halogenated compounds in the atmosphere are of great environmental concern due to their demonstrated negative effect on atmospheric chemistry and climate. Detailed knowledge of the emission budgets of halogenated compounds has to be gained to understand better their specific impact on ozone chemistry and the climate. Such data are also highly relevant to guide policy decisions in connexion with international agreements about protection of the ozone layer. In selected cases, the relevance of specific emission sources for certain compounds were unclear. In this study we present new and comprehensive evidence regarding the existence and relevance of a volcanic contribution of chlorofluorocarbons (CFCs), hydrofluorocarbons (HFCs), hydrochlorofluorocarbons (HCFCs), halons (bromine containing halo(hydro)carbons), and fully fluorinated compounds (e.g. CF4 and SF6) to the atmospheric budget. METHODS: In order to obtain new evidence of a volcanic origin of these compounds, we collected repeatedly, during four field campaigns covering a period of two years, gases from fumaroles discharging over a wide range of temperatures at the Nicaraguan subduction zone volcanoes Momotombo, Cerro Negro and Mombacho, and analysed them with very sensitive GC/MS systems. RESULTS AND DISCUSSION: In most fumarolic samples certain CFCs, HFCs, HCFCs, halons, and the fully fluorinated compounds CF4 and SF6 were present above detection limits. However, these compounds occur in the fumarole gases in relative proportions characteristic for ambient air. CONCLUSION: This atmospheric fingerprint can be explained by variable amounts of air entering the porous volcanic edifices and successively being incorporated into the fumarolic gas discharges. Recommendation and Outlook. Our results suggest that the investigated volcanoes do not constitute a significant natural source for CFCs, HFCs, HCFCs, halons, CF4, SF6 and NF3.     

全球二氧化碳排放权交易市场的分析与展望

京都议定书提出了发达国家削减二氧化碳排放量的具体目标及削减方案。因此二氧化碳排放权交易成为关注的热点。在对排放权交易市场的特性．作用及利害关系分析的基础上．提出排放权交易市场将带动一批相关的服务业发展。英国，日本在国内建立交易市场的动作和进展．值得重视和借鉴。     

The Ecological Significance of the Coexistence of Sulphur Dioxide and Hydrogen Sulphide in Volcanic Fumaroles

The relative concentrations of hydrogen sulphide and sulphur dioxide in volcanic gases cannot be explained simply by the temperatures and pressures, and appear as the result of the influence of different natural factors. SO₂ is directly related to magma degassing, while H₂S can be produced by the reaction of acidic solutions on dispersed sulphide minerals.

As long as these inputs to the surface environment are of moderate extent, then readjustment of redox conditions to an equilibrium situation will occur; a permanent disequilibrium will result in increased contributions of any component.

A wide spectrum of trace elements is normally associated with the presence of sulphur compounds in volcanic areas; their importance can be estimated for any system on the basis of the quantitative relationship between the oxidized and the reduced sulphur species. Extensive polluting effects can be produced by a continuous flow from a deep magmatic source, while minor consequences are associated with a re-circulation in the surface environment of heavy metals from previous volcanic activities.     

五里峡水库初级生产力对水气界面二氧化碳和甲烷排放速率时空变化的影响

近年来水库温室气体备受关注,为揭示水库水气界面CO_2和CH_4在时间和空间上的变化特征,于2016年7~12月采用静态箱法在五里峡水库对其CO_2和CH_4排放速率进行4次监测,并测试微型光合生物初级生产力等.结果表明,五里峡水库夏季为大气CO_2的汇,变化范围在-30.14~-3.47 mg·(m~2·h)~(-1),秋、冬季均为大气CO_2的源,变化范围在15.57~115.06 mg·(m~2·h)~(-1).甲烷排放速率在夏季变化幅度明显,变化范围在0.08~1.03 mg·(m~2·h)~(-1),而在秋、冬季变化稳定,变化范围在-0.07~0.43 mg·(m~2·h)~(-1).受水库周期性蓄水和排水影响,CO_2和CH_4排放速率在空间上表现为水库消落带和坝尾较低而库区较高的分布格局.此外,CO_2和CH_4排放速率时空变化与微型光合生物初级生产力分别呈显著负相关和正相关(r为-0.477和0.771).这是因为产甲烷菌能够将夏季微型光合生物固定的有机碳转化成CH_4释放到大气中,从而使微型光合生物对水圈CO_2和CH_4循环产生负反馈效应和正反馈效应.因此,本研究结果为进一步评估微型生物对岩溶水体碳循环的贡献提供了理论依据.     

秦岭油松林不同坡位土壤CO2、CH4、N2O通量研究

在秦岭南坡火地塘林区天然次生油松林内选取上、中、下3个坡位,采用静态箱-气相色谱法对土壤CO_2、CH_4、N_2O通量进行了1年的监测.结果表明,坡位间土壤质地和水分的差别是引起不同坡位CO_2与N_2O通量差异的主要原因:下坡位土质为壤土,水分适宜,CO_2平均排放量为(156.49±9.72)mg·m~(-2)·h~(-1),CH_4平均吸收量为(77.43±14.27)μg·m~(-2)·h~(-1),都处于3个坡位间最高水平;中坡位土质为粉砂壤土,土壤粒径小,透气性差,CO_2排放量和CH_4吸收量均为3个坡位间的最小值,N_2O平均排放量为(9.57±0.66)μg·m~(-2)·h~(-1),为3个坡位间的最高值,且显著高于上坡位土壤N_2O通量(p0.01);上坡位土质为砂壤土,土壤孔隙度大且地表植被少,N_2O平均排放量为(5.59±0.74)μg·m~(-2)·h~(-1),为3个坡位间的最小值.总体来说,油松林土壤是CO_2、N_2O的排放源,是CH_4的吸收汇.3个坡位CO_2年通量具有明显的季节规律,表现为倒"S"形变化,且与土壤温度显著正相关(p0.01).受冻融循环的影响,N_2O主要在非生长季大量排放;生长季末期,受降雨事件影响,油松林中坡位出现N_2O吸收峰值.生长季上、下坡位CH_4吸收峰值的出现同样伴随着降雨事件的发生,非生长季,中坡位因土壤水分过高而出现短暂的CH_4排放现象.不同坡位土壤温室气体的全球增温潜势(Global Warming Potential,GWP)从大到小依次是上坡位、下坡位和中坡位.     

烟气二氧化硫分析仪采样计量泵的研制与应用

采样误差是抽样式污染源气体分析仪最大的误差来源之一。采样的气体浓度越高 ,越需要高精度的气体采样计量泵。文章介绍的计量泵精度可达 0 .1 1 %。应用该计量泵可以基本消除气体分析仪采样方面的计量误差     

An improved gas chromatography for rapid measurement of CO2,CH4 and N2O

Combining improved injector, gas line and valve-driving modules, a GC equipped with FID and ECD, could simultaneously measure CH4, CO2 and N2O in an air sample within 4 min. Test results showed that the system has high sensitivity, resolution and precision; the linear response range of the system meets the requirement of in situ flux measurements. Thus, the system is suitable for monitoring fluxes of main greenhouse gases in terrestrial ecosystem since it is easy to use, efficacious, stable and reliable to collect data.     

Baseline options and greenhouse gas emission reduction of clean development mechanism project in urban solid waste management

The Clean Development Mechanism (CDM) was adopted in the Kyoto Protocol as a flexibility mechanism to reduce greenhouse gases (GHGs) and has been started with such projects as improving efficiency of individual technology. Although applying various countermeasures to urban areas has significant potentials for reducing GHGs, these countermeasures have not been proposed as CDM projects in the practical stage. A CDM project needs to be validated that it will reduce GHGs additionally compared with a baseline, that is, a predictive value of GHG emissions in the absence of the project. This study examined the introduction of solid waste incineration with electricity generation into three different cities, A, B and C. The combination of main solid waste treatment and fuel source are landfill and coal, respectively, in City A, incineration and natural gas in City B, and landfill and hydro in City C. GHG emission reductions of each city under several baseline options assumed here were evaluated. Even if the same technology is introduced, the emission reduction greatly varies according to the current condition and the future plan of the city: 1043–1406 kg CO₂/t of waste in City A, 198–580 kg CO₂/t in City B, and wide range of zero to over 1000 kg CO₂/tin City C. Baseline options also cause significant difference in the emission reduction even in the same city (City C). Incinerating solid waste after removing plastics by source separation in City B increased GHG emission reduction potential up to 730–900 kg CO₂/t, which enhances the effectiveness as a CDM project. This revised version was published online in August 2006 with corrections to the Cover Date.     

大气硫循环中的自然硫释放研究

基于当前可获得的与该课题相关资料 ,综述了陆地生态系统对全球硫总量的贡献。第 1部分阐述了已熟知的自然硫源——海洋硫循环的了解。第 2部分给出了陆地硫循环的基本情况及各化学组分和源的相对重要性。第 3部分给出以前报导的各硫源的几种主要含硫气体的通量值 ,通过比较推导出对应各环境的代表性硫通量值。最后的第 4部分作为总结讨论了克服早先自然生态系统硫循环研究测定中的各种局限的方向并提出建议。