烟气平均流速自动测量及其自动检测装置

通过对烟道"速度场常数"的研究,提出了利用速度场常数监测烟道烟气平均流速的方法,同时研制出速度场常数自动检测装置.解决了烟道烟气平均流速自动监测的技术难题.经实践检验:所研究的监测方法正确,检测装置结构合理,监测结果稳定、可靠.     

辽宁省工业污染源数量变化及驱动因素分析

以1998─2005年辽宁省14个城市工业污染源数量数据为基础,分析了工业污染源在省、市、区域3个层面上数量变化的特征;指出造成差异的2个主要影响因素,即经济发展和国家政策;讨论了工业污染源数量变化与废水排放量之间的关系.结果表明:辽宁省工业污染源数量区域差异变小,但仍然集中在沈阳、大连和抚顺等城市,营口工业污染源数量增加较快;污染源空间分布与经济发展区域特征有较好的相关性,哈尔滨-大连产业带也成了“污染密集带”;经济发展是污染源数量变化的重要影响因素;国家产业政策通过影响经济从而间接影响污染源数量和质量,而环保政策则直接影响环境保护的方向和环境治理的力度.      

区域输送对天津臭氧污染的影响

采用大气化学模式定量估算2019年4月～9月区域输送对京津冀区域,特别是天津市O₃浓度的影响,分析天气形势和气象条件与区域输送的关系.结果显示,京津冀区域13个城市O₃以区域输送贡献为主,不同城市O₃差异较大,天津本地贡献占比24%,区域输送以京津冀区域其他城市和山东为主,共贡献48.3%.低压、低压前和低压后形势下,O₃区域输送占比最高.途径天津偏南区域的气流是造成天津高浓度O₃污染的重要因素,也是区域输送的主要路径.随着O₃浓度升高,输送贡献占比呈逐步上升趋势,重度污染时本地生成与区域输送贡献相当.一次典型O₃污染过程分析表明,高温强辐射天气和有利的天气形势促进O₃本地生成,西南气流和弱下沉气流下的区域输送共同维系了这场持续3d的连续污染过程.     

豫境黄淮海平原土壤重金属背景值研究

长期缺少豫境黄淮海平原土壤重金属背景值数据,很多学者不得不用河南省土壤或中国潮土元素背景值作为标准评价重金属污染.那么,豫境黄淮海平原土壤重金属背景值与河南省土壤、中国潮土是否存在差异？平原内部是否存在重金属背景值的空间差异？这是影响评价结果可靠性的关键,需要开展研究.采用10 km×10 km网格法,在研究区沙河干流以南(南区)和以北(北区)分别采集土壤表层样品336份和561份.用电感耦合等离子体发射质谱法(ICP-MS)测定样品Cd、Cr、Pb、Cu、Zn和Ni含量,用原子荧光光度法(AFS)法测定样品Hg、As含量.在重金属含量异常值剔除和数据分布检验基础上,分别确定南区和北区重金属背景值.结果表明,南区土壤Hg、As、Cd、Cr、Pb、Cu、Zn和Ni背景值分别为0.066、4.11、0.130、56.72、20.97、23.31、59.21和24.03 mg·kg^-1,北区上述重金属的背景值分别为0.061、7.45、0.129、51.92、18.96、22.72、66.96和27.16 mg·kg^-1.北区土壤As、Zn和Ni背...     

Mathematical equivalence of geometric mean fitness with probabilistic optimization under environmental uncertainty

Natural selection can be considered as optimising fitness. Because ‘mean’ fitness is maximized with respect to the genotypes of carriers, traditional theory can be viewed as a statistical theory of natural selection. Probabilistic optimisation is a way to incorporate such uncertainty into optimality analyses of natural selection, where environmental uncertainty is expressed as a probability distribution. Its canonical form is a weighted average of fitness with respect to a given probabilistic distribution. This concept should be applicable to three different levels of uncertainty: (1) behavioural variations of an individual, (2) individual variations within a generation, and (3) temporal change over generations (geometric mean fitness). The former two levels are straightforward with many empirical evidences, but the last category, the geometric mean fitness, has not well understood. Here we studied the geometric mean fitness by taking its logarithm, where the log growth rates become the fitness value. By further transforming the log growth rates, the fitness of log growth rates becomes its linear function. Therefore, a simple average of these distributions becomes the fitness measure across generations and consideration of variance discount or the entire probability distributions becomes unnecessary. We discuss some characteristic features of probabilistic optimization in general. Our view is considered a probabilistic view of natural selection, in contrast with the traditional statistical view of natural selection.     

New parameterization scheme for effective indices for emissions from road transport

The local to regional processes of chemical transformations, washout and dry deposition cannot be directly resolved in global scale models, they rather need to be parameterized. A suitable way to account for the non-linearity, e.g., in chemical transformation processes, is the use of effective emission indices (EEIs). EEI translate the actual (small scale) emissions into input for global scale models, partially accounting for unresolved processes occurring shortly after the release of the emissions.The emissions from the road traffic have some specifics, because of which the concept of deriving EEI from the interaction of an instantaneous plume with the ambient air is perhaps not so convenient. A new parameterization scheme for the EEI from the road transport is suggested in the present paper, based on few simplifying assumptions and introducing the adjoin equations approach, which makes it possible to achieve unified, not depending on the specific emission pattern, procedure for calculating the EEI from road traffic.     

典型时段区域污染过程分析及系统聚类法的应用

应用系统聚类法对2008年12月4─17日全国86个城市由空气污染指数(API)反算的ρ(PM₁₀₎进行聚类分析.结果表明:86个城市可以分为7个分区;根据ρ(PM₁₀₎的区域同步性特征及实况天气背景分析对7个分区进行了调整. 在12月4─17日的区域污染过程中,华北和华东2个地区为全国ρ(PM₁₀₎的高值区. 对华北和华东地区城市群ρ(PM₁₀₎的区域环境过程同步演变特征进行了对比分析,并根据天气型演变规律对形成原因进行了研究,建立了城市及区域环境污染过程与天气型背景的关系概念模型,揭示出天气型组合系统、分布、尺度、移动和演变是造成大气环境质量区域性、过程性特征和ρ(PM₁₀₎峰谷值出现的主要原因. 用聚类分析方法和所提出的概念模型可对我国城市和区域环境污染分区控制和成因进行深入研究.      

北京奥运会及残奥会期间PM10质量浓度演变特征及成因

2008年8─9月北京及周边各省市ρ(PM₁₀₎明显低于2006─2007年同期值. 结合污染物监测数据及气象资料,采用影响因子资料统计以及典型个例诊断对比法,研究造成北京奥运会及残奥会期间低ρ(PM₁₀₎的原因. 对2006─2008年同期风速的统计表明,2008年7─10月北京各月平均风速均低于往年,2 m/s以上的风发生频率低于往年,不利于大气污染物扩散. 2008年8月北京月降水量与2005年接近,但ρ(PM₁₀₎明显优于2005年,可见降水并不是该次ρ(PM10)月均值低的原因. 对比2006─2008年8─9月典型相似累积型天气型背景影响下ρ(PM₁₀₎日均值及演变过程发现,2008年ρ(PM₁₀₎日均值及演变曲线均低于往年. 根据对影响因子统计和北京及其周边省(市、区)严格的减排措施等分析,指出天气形势及其伴生的气象因素演变可能影响ρ(PM10)日均值波动,但六省(市、区)协同减排是保障优质空气质量的主要原因.      

Are network indices robust indicators of food web functioning? A Monte Carlo approach

Indices based on network theory are often used to describe food web functioning. These indices take as input food web flows that are estimated based on merging of (scarce) data with linear inverse methods (LIMs). Due to under sampling, most food webs are highly uncertain and can only be quantified within a specific uncertainty range. The linear inverse method (LIM) can estimate food web flows using a variety of techniques, e.g. the parsimonious or minimum norm (MN) solution, which selects one food web, based on a quadratic minimization technique or the Monte Carlo solution where a finitely many random solutions are generated which are then averaged. We use the Monte Carlo approach (MCA) to estimate the values of several indices from four published food webs, the Gulf of Riga for the autumn, summer and spring seasons, and the Takapoto atoll system. We first show that network indices are much better constrained than the uncertain food webs from which they are calculated. Therefore, even in the face of food web uncertainty, they are robust estimators of food web functioning. We then use the MCA-derived network indices to generate cumulative density functions for each index. These serve to compute the probabilities of the MN indices estimates being an extreme solution as compared to the median values. Our findings show that 82% of the MN solutions are smaller than the MCA solutions, and 63% of the network indices are significantly under-estimated.     

RELATIVE REGIONAL VULNERABILITY OF WATER RESOURCES TO CLIMATE CHANGE1

ABSTRACT: Changes in global climate may alter hydrologic conditions and have a variety of effects on human settlements and ecological systems. The effects include changes in water supply and quality for domestic, irrigation, recreational, commercial, and industrial uses; in instream flows that support aquatic ecosystems, recreation uses, hydropower, navigation, and wastewater assimilation; in wetland extent and productivity that support fish, wildlife, and wastewater assimilation; and in the frequency and severity of floods. Watersheds where water resources are stressed under current climate are most likely to be vulnerable to changes in mean climate and extreme events. This study identified key aspects of water supply and use that could be adversely affected by climate change, developed measures and criteria useful for assessing the vulnerability of regional water resources and water dependent resources to climate change, developed a regional database of water sensitive variables consistent with the vulnerability measures, and applied the criteria in a regional study of the vulnerability of U.S. water resources. Key findings highlight the vulnerability of consumptive uses in the western and, in particular, the southwestern United States. However, southern United States watersheds are relatively more vulnerable to changes in water quality, flooding, and other instream uses.