Evaluating the utility and seasonality of NDVI values for assessing post-disturbance recovery in a subalpine forest

Forest disturbances around the world have the potential to alter forest type and cover, with impacts on diversity, carbon storage, and landscape composition. These disturbances, especially fire, are common and often large, making ground investigation of forest recovery difficult. Remote sensing offers a means to monitor forest recovery in real time, over the entire landscape. Typically, recovery monitoring via remote sensing consists of measuring vegetation indices (e.g., NDVI) or index-derived metrics, with the assumption that recovery in NDVI (for example) is a meaningful measure of ecosystem recovery. This study tests that assumption using MODIS 16-day imagery from 2000 to 2010 in the area of the Colorado’s Routt National Forest Hinman burn (2002) and seedling density counts taken in the same area. Results indicate that NDVI is rarely correlated with forest recovery, and is dominated by annual and perennial forb cover, although topography complicates analysis. Utility of NDVI as a means to delineate areas of recovery or non-recovery are in doubt, as bootstrapped analysis indicates distinguishing power only slightly better than random. NDVI in revegetation analyses should carefully consider the ecology and seasonal patterns of the system in question.     

Just so that we don't miss it: A critical view on the meaning of decision in IA

Impact assessment (IA) tools are targeted at decisions and decision-making in theory and in practice. Often described as decision support instruments, most IA are driven by the grand purpose of providing for informed decision-making. In practice this often means IA tends to be more concerned with the information to be provided than with the outcomes of IA and its relevance to the decision(s), and decision-makers(s) to which it should be targeted. Decisions and decision-making are, however, understood in many different ways, and actors involved in decision-making may therefore act widely different with diverse results. Therefore, distinguishing which decisions, and to which decision-makers IA are targeted at, is arguably indispensable to enhance IA effectiveness. Based on an overview of decision-making theory, this paper searches for the understanding of decision and decision-making in IA by exploring how it is conceived in guidance documents. Guidance documents have a prominent role in defining IA practice, and the explicit and implicit recognition of decision-making in guidance is therefore relevant to investigate in order to understand how IA relates to decision-making. With a focus on guidance documents related to the European Union Directive on environmental assessment of plans and programmes, this paper scrutinises four guidance documents and discusses the implications of the identified understandings of decision-making to the practice of IA. The key finding of this paper is that legislation-oriented guidance documents appear to miss to reflect the different forms of decision-making, and primarily depicts decision-making as a single, often timeless and faceless moment. The implications for practice are discussed including reflection on how to describe the nature of decision-making in guidance documents.     

Empirical Estimation of Virtual Point Source Height Over a Bank of Coke Ovens

This paper addresses an empirical method of assessment of the height of a virtual point source. In order to achieve such assessment, three planes defining the location of a virtual point source in a space are created and formulas describing the geometry of observer’s sight and plume orientation are used. Data for calculations are obtained on a basis of plume photographs. The final position of a virtual emission point is described by a set of its coordinates in the Cartesian coordinate system. Presented method may be applied as a means to verify and validate the existing formulas describing the rise of plume above the stack exit or as a tool enabling acquisition of information for the sake of creating new formulas of this type. The calculation of the location of a virtual point source ascribed to the point emission from the roof of the bank of coke oven is presented and illustrated with photographs which reveal position of plume, adequate planes, axes and characteristic objects.     

基于激光雷达技术的粉尘污染源监测

针对粉尘污染点源数量多、夜间偷排偷放监测难等问题,环保监测迫切需要发展新一代遥感监测技术,为环境保护提供技术支撑。激光雷达具有远距离、全天时监测的优势,可实现对污染源的客观、全天时监测。为了验证激光雷达主动遥感技术监测粉尘污染源排放的可行性,在河北省组织了一次粉尘污染源的Lidar监测实验,在进行距离校正的基础上,发展了Lidar点源污染监测指数因子方法。结果表明:烟尘排放浓度与Lidar指数因子具有较好的一致性,校正决定系数可达0.94。在稳定排污的情况下研究Lidar指数因子的限值,结果显示,将指数因子的限值设为2.3时,与在线监测的一致性可以达到99%以上。     

Continuous monitoring of NO in flue gas based on wavelet decomposition

In this paper, a new algorithm for nitric oxide (NO) measurement based on multi-scale wavelet decomposition is proposed. The algorithm uses one-dimensional discrete multi-scale wavelet decomposition to analyze the transmission spectrum of flue gas. Through the different scales of decomposition, the relation between the absorption characteristics of NO gas and the reconstruction of wavelet coefficients is found. The DB9 wavelet can obtain the most obvious absorption characteristics of the NO gas. After calibration, the algorithm is used to measure the concentration of the mixture of NO and SO(2). The results show that the algorithm is efficient towards SO(2) absorption interference with a full-scale error less than ± 0.4% in laboratory conditions. The algorithm was then applied to field measurements with an overall standard deviation of 8.37 mg m(-3), which is better than 18.92 mg m(-3) determined by the least squares method. Under the interference of desulfurization, the full-scale measurement errors are less than ± 2%. In addition, the algorithm avoids using the reference spectrum, thereby reducing the aging of the light source effectively. It has strong anti-interference capability, good durability, and practicality in the continuous monitoring of NO.     

典型大气污染源动态排放清单编制方法及应用研究

随着环境空气质量精细化管理要求的提高,在应对重污染天气过程中,对大气污染源排放清单的时间分辨率提出了更高的要求。文章从固定源、移动源、油气储运源等方面探讨了大气污染源动态排放清单编制技术方法,并选取某城市进行了应用计算。结果表明,通过获取动态更新的数据,移动源的船舶、机动车、飞机可以逐时分析污染物排放量变化;固定源和油气储运源可以逐日分析。同时与相关指南算法进行定量比较,探讨了精细化改进方法及可能存在的问题,为建立更精细化动态排放清单提供有益参考。     

Estimation of the temporal and spatial distribution of dust concentration over China by combining PM10 and conventional meteorological observations

In this paper, we will present a simple algorithm to estimate the temporal and spatial distribution of dust mass concentration by combining PM10 and conventional meteorological observations. The efficiency of the algorithm has been demonstrated by applying it to analyze the dust source, transport, and dissipation of the dust storm which occurred in the west region of Pa-tan-chi-lin Desert at 0200 BST 27 March, 2004.     

厂界噪声背景值修正问题的讨论

在实际计算中 ,按照国家标准 (GB1 2 3 4 9-90 )扣除背景噪声值常常会与待测声源的实际声级值产生较大的误差。利用对噪声源的实际测量数据 ,探讨这种误差产生的原因及结果 ,并建议今后采用计算结果列表查找或者直接用公式计算的方法扣除背景噪声 ,以消除因数据处理不当而产生的误差。     

Pre-incubation in soil improves the nitrogen fertiliser value of hair waste

Global generation of human hair waste and its disposal at landfills could contribute to the leaching of nitrates into ground water. High concentrations of nitrogen (N) and other elements suggest that the waste could be a source of plant nutrients and differences in ethnic hair types could affect nutrient release and fertiliser value. The objective of this study was to determine the effects of hair type, as an N source, and pre-incubation time on dry-matter yield, nutrient uptake by spinach (Spinacia oleracea L.) and residual soil nutrients. Salons in Pietermaritzburg provided bulk African and Caucasian hair waste, without distinguishing age, sex, health status or livelihood of the individuals. The hair waste was analysed for elemental composition. A pot experiment was set up under glasshouse conditions. The hair waste was incorporated (400 kg N ha^?1) into a loamy oxisol and pre-incubated for 0, 28, 56 and 84 days before planting spinach. Potassium (K) and phosphorus (P) were corrected to the same level for all treatments. Spinach seedlings were then cultivated for 6 weeks. Shoot dry-matter and the uptake of all nutrients, except P, were increased by the pre-incubation of hair. African hair pre-incubated for 28 days resulted in greater dry-matter, N, K, Mn and S uptake than Caucasian hair. Increasing pre-incubation resulted in a decline in the residual soil pH and exchangeable K. The findings suggested that pre-incubation improves the N fertiliser value of hair and that African hair has greater value than Caucasian hair when pre-incubated for a short period.     

Nitrous oxide emissions from waste water

The estimation of nitrous oxide emissions is complicated by the high degree of uncertainty on the emission factors involved and by the limited acquaintance with all significant nitrous oxide sources. A potentially important source for which emission data are lacking is the sewage system transporting waste water from human activities. For this study an experimental measurement campaign has been carried out on waste water sampled at different sewage treatment plants. The nitrous oxide developing from the water samples was monitored by means of gas chromatography. The methodological analysis was based on the concentration/time curves obtained. Our results indicate that the formation of nitrous oxide from the waste water matrices results from microbiological denitrification. We deduced tentative emission factors for the waste water types studied.     

Neural Network Based Automated Interpretation Algorithm for Combined Geophysical Soundings in Coastal Zones

The fresh water availability in coastal aquifers is an important problem faced by a major part of world’s population dwelling there. For in situ and dynamic characterization of seawater encroachment into coastal aquifers, electrical geophysical methods are better suited. However, the resolving power of such data in distinguishing saline sands from moist clays in the subsurface is very poor. To meet this aspect and also the problem of analyzing voluminous data sets, we propose a feed forward back-propagation neural network (BPNN) based approach for the analysis of combined vertical electrical and induced polarization soundings. Our method is tested on synthetic data computed from available geo-electric sections and prevailing subsurface geological information of coastal aquifers of East Coast of India.The synthetic data are comprised of 18 combined soundings spread over five profiles. 15 out of 18 are used for training the BPNN, while 3 are used for testing. The trained BPNN (one node each in each of the input and output layers and 18 hidden nodes) showed 84.85% accuracy in testing phase for distinguishing clays from saline sands.Our method is also tested on real data concerning a shaly aquifer in Bahia, Brazil yielding an overall accuracy of 84.9%, comparable to that of synthetic case; thereby validating our approach.     

Sequential optimal monitoring network design and iterative spatial estimation of pollutant concentration for identification of unknown groundwater pollution source locations

One of the difficulties in accurate characterization of unknown groundwater pollution sources is the uncertainty regarding the number and the location of such sources. Only when the number of source locations is estimated with some degree of certainty that the characterization of the sources in terms of location, magnitude, and activity duration can be meaningful. A fairly good knowledge of source locations can substantially decrease the degree of nonuniqueness in the set of possible aquifer responses to subjected geochemical stresses. A methodology is developed to use a sequence of dedicated monitoring network design and implementation and to screen and identify the possible source locations. The proposed methodology utilizes a combination of spatial interpolation of concentration measurements and simulated annealing as optimization algorithm for optimal design of the monitoring network. These monitoring networks are to be designed and implemented sequentially. The sequential design is based on iterative pollutant concentration measurement information from the sequentially designed monitoring networks. The optimal monitoring network design utilizes concentration gradient information from the monitoring network at previous iteration to define the objective function. The capability of the feedback information based iterative methodology is shown to be effective in estimating the source locations when no such information is initially available. This unknown pollution source locations identification methodology should be very useful as a screening model for subsequent accurate estimation of the unknown pollution sources in terms of location, magnitude, and activity duration.     

Evaluation of the urban/rural particle-bound PAH and PCB levels in the northern Spain (Cantabria region)

The aim of the present study was to evaluate the polycyclic aromatic hydrocarbon (PAH) and polychlorinated biphenyl (PCB) levels in PM(10) and PM(2.5), at one rural and three urban sites in the Cantabria region (northern Spain). From all of these pollutants, benzo(a)pyrene is regulated by the EU air quality directives; its target value (1?ng/m(3)) was not exceeded. The concentration values of the studied organic pollutants at the studied sites are in the range of those obtained at other European sites. A comparison between the rural-urban stations was developed: (a) PAH concentration values were lower in the rural site (except for fluorene). Therefore, the contribution of local sources to the urban levels of PAHs seems relevant. Results from the coefficient of divergence show that the urban PAH levels are influenced by different local emission sources. (b) PCB rural concentration values were higher than those found at urban sites. Because no local sources of PCBs were identified in the rural site, the contribution of more distant emission sources (about 40?km) to the PCB levels is considered to be the most important; the long-range transport of PCBs does not seem to be significant. Additionally, local PAH tracers were identified by a triangular diagram: higher molecular weight PAHs in Reinosa, naphthalene in Santander and anthracene/pyrene in Castro Urdiales. A preliminary PAH source apportionment study in the urban sites was conducted by means of diagnostic ratios. The ratios are similar to those reported in areas affected by traffic emissions; they also suggest an industrial emission source at Reinosa.     

Evaluation of Point and Diffuse Sources of Nutrients in a River Basin on Base of Monitoring Data

The methodology of materials accounting is presented and applied to developing nutrient balance (nitrogen and phosphorus) in a river basin. The method is based on the balance principle: inputs and outputs of each nitrogen and phosphorus related sub-systems were balanced. The application of the methodology strategies was illustrated by means of a case study of the Krka river, Slovenia. Different pathways of emission to surface waters were taken into account: WWTP discharges, direct discharges, erosion/runoff and baseflow. Total annual emission into the river Krka was estimated to be 362 tonnes N/year and 73.3 tonnes P/year. The main sources of nitrogen are diffuse sources, emitted via baseflow (52%). Other important sources are effluents from WWTP, which account for 36% of total emissions. Other sources like erosion and direct discharges to surface water (animal manure, industry, households) are of lower magnitude. Erosion is main source of phosphorus emission (55% of total emission), WWTP effluents account for 37% of total emission, while other sources are less important. Besides reduction of point sources by means of wastewater collection and implementation of nutrient removal technology, managing agricultural nitrogen and phosphorus to protect water quality should become a major challenge in the Krka river basin.     

Evaluation of the best compromise between the urban air quality monitoring resolution by diffusive sampling and resource requirements

The need to collect data representative of overall urban pollution is all-important in order to monitor the population exposure. High spatial resolution monitoring using diffusive samplers allows studying of the urban pollutant distribution, thus enabling deeper investigation of their generation and diffusion mechanisms. Nevertheless, such a monitoring campaign has a certain cost. In this study we point out how to find the best compromise between the number of necessary measurements and the affordable costs for monitoring campaigns. We also describe an innovative method for the proper design of a fixed urban monitoring network by means of preliminary high spatial resolution campaigns using diffusive samplers. Four European capital cities (Dublin, Madrid, Paris and Rome) were monitored six times, each time for seven days. Benzene, toluene, ethylbenzene, xylenes (BTEX) and NO(2) concentrations were measured at 146 sites in Dublin, 293 in Madrid, 339 in Paris and 290 in Rome. Multiscale grids have been drawn which ranged in mesh size from 500 m to 2 km. The statistical processing of data produced a twofold result: the creation of isoconcentration maps with geostatistical procedures, and an algorithm aimed at locating the minimum number of sampling sites where the fixed monitoring stations should be placed. Average urban levels estimated on the basis of these selected sites differ by less than 8% from those calculated on the whole populations of the sampled points. The aim of this work is to investigate how far the resolution of a monitoring campaign of urban pollution by diffusive sampling can be reduced, thus making the monitoring less expensive in terms of human and financial resources, while preserving the same quality of the results that could be achieved with a higher resolution. We found that there is no significant loss of information when the resolution of the monitoring grid for BTEX is lowered to a mesh size of 1.85 km, that is a sampling site each 3.4 km(2), and that the minimum number of sampling sites to be used is N = 0.29 A, where A is the urban surface to be monitored (in km(2)). As the spatial distribution of NO(2) is less sensitive to the distance from the emission source than that of BTEX, this relationship could be retained as a valid lower limit for the mesh grid size also for NO(2) monitoring.     

Multi-objective optimization of air quality monitoring

A new method for multi-objective optimization of air quality monitoring systems based on satellite remote sensing of the troposphere is described in this work. The technique uses atmospheric turbidity as surrogate for air pollution loading. Through inverse chemical modeling and ancillary information the respective patterns of primary gaseous and particle pollutants are inferred. The optimization algorithm uses the resulting maps of ambient air pollution as input. It focuses on the gain of information with regard to human exposure to high pollution, potential impact on cultural heritage, compliance to ambient air quality standards, monitoring key point and area source emissions, as well as on the associated cost. Application of the method in Brescia, Italy showed its significant potential for improving the cost-effectiveness of air quality monitoring networks at the urban and regional scales.     

Soil Gas Volatile Organic Compound Concentration Contours for Locating Vadose Zone Nonaqueous Phase Liquid Contamination

Diffusion of VOC from cylindrical vadose zone domains contaminatedwith distributed nonaqueous phase liquid is examined in the steadystate approximation. The effects of first-order biodegradation and ofan extended underlying pool of LNAPL floating on the water table belowthe cylindrical domain are explored by means of an orthogonal functionsapproach. The distribution of VOC in the vadose zone above a floatingcircular LNAPL pool of finite size is explored by a numerical method.The results provide information useful in estimating the spacing anddepth at which soil gas samples should be taken in order to detect thepresence of such source areas. Comparison of model results with soilgas VOC measurements at various depths also provides insight into theextent to which natural biodegradation of the VOCs is taking place.     

完善环境监测技术监督体系的思考

阐述了环境监测技术监督的概念及其重要性和必要性,分析了由于认识不到位、手段欠缺、机制不完善等原因而导致的技术监督作用的弱化表现。提出开展环境质量现状、污染源状况、开发区环境质量、环境管理措施绩效、监测科研课题等多项技术监督,利用报告、会议、区域目标考核等形式,建立多部门联动的环境质量分析会机制、项目审批过程的跟踪监测机制、环境管理污染防治的目标考核机制、监察处罚的效果点评机制、环境监测部门内部的资源整合机制,进一步完善技术监督体系。     

Heavy metals partitioning in sediments of the Kabini River in South India

Cu, Cr, Fe, Mn, Ni, Pb, and Zn in the sediments of the Kabini River, Karnataka, India was studied to determine the association of metal with various geochemical phases by sequential extraction. The variations of heavy metal concentration depend on the lithology of the river basin and partly on anthropogenic activities. The Kabini River sediments are dominated by Sargur supracrustals with amphibolites, gneisses, carbonates, and ultrabasic rocks weathering into gneissic and serpentine soils carrying a natural load of cationic heavy metals. The source of heavy metals in the Kabini riverbed sediments is normally envisaged as additional inputs from anthropogenic over and above natural and lithogenic sources. Geochemical study indicates the metals under study were present mostly in the least mobilizable fraction in the overlying water and it is concluded that heavy metals in these sediments are to a great extent derived from multisource anthropogenic inputs besides geochemical background contributions The results show that lead and chromium have higher potential for mobilization from the sediment due to higher concentration at the exchangeable ion and sulfide ion bounded, also Cu and Pb have the greatest percentage of carbonate fraction, it means that the study area received inputs from urban and industrial effluents. Association of the Fe with organic matter fraction can be explained by the high affinity of these elements for the humic substances. Further, Zn and Ni reveal a significant enrichment in sediment and it is due to release of industrial wastewater into the river. These trace metals are possible contaminants to enter into aquatic and food chain.     

内河涌氨氮污染的特征及其来源的研究

以佛山市雅瑶涌为研究实例,探讨了珠江三角洲河网地区围内河涌氨氮污染的特征,并对氨氮的来源进行了研究。内河涌的氨氮污染逐年严重,并呈现季节性的变化,已成为最主要的污染因子。研究结果表明,畜牧水产业和非点源都是比较显著的氨氮污染源,但未经集中式污水处理厂处理的生活污水,则成为内河涌最重要的氨氮污染源。