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81.
A series of modifications were implemented in MM5 simulation in order to account for wind along the Santa Clarita valley, a north–south running valley located in the north of Los Angeles. Due to high range mountains in the north and the east of the Los Angeles Air Basin, sea breeze entering Los Angeles exits into two directions. One branch moves toward the eastern part of the basin and the other to the north toward the Santa Clarita valley. However, the northward flow has not been examined thoroughly nor simulated successfully in the previous studies. In the present study, we proposed four modifications to trigger the flow separation. They were (1) increasing drag over the ocean, (2) increasing soil moisture content, (3) selective observational nudging, and (4) one-way nesting for the innermost domain. The Control run overpredicted near-surface wind speed over the ocean and sensible heat flux, in an urbanized area, which justifies the above 1st and 2nd modification. The Modified run provided an improvement in near-surface temperature, sensible heat flux and wind fields including southeasterly flow along the Santa Clarita valley. The improved MM5 wind field triggered a transport to the Santa Clarita valley generating a plume elongated from an urban center to the north, which did not exist in MM5 Control run. In all, the modified MM5 fields yielded better agreement in both CO and O3 simulations especially in the Santa Clarita area.  相似文献   
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The stock of the European eel (Anguilla anguilla L.) continues to decline and has reached a new minimum in 2011. Poor health status of the spawners due to organic contaminants is one of the possible causes for this dramatic situation. Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous contaminants, which are rapidly metabolized in vertebrates. EROD (ethoxyresorufin-O-deethylase) and GST (glutathione-S-transferase) are two enzymes involved in PAH detoxification in fish. In this study, PAH metabolites as well as EROD and GST activity in a large, comprising dataset of more than 260 migratory and pre-migratory eels from five large German river basin districts were used to describe PAH exposure and its metabolism as possible indicators for the habitat quality for eels. Eel from the river Elbe appear to be moderately contaminated with PAH. Highest mean values of PAH metabolites were analysed in fish from the river Rhine. However, the results suggest that contaminants such as PAH are metabolized in the fish and may have contributed to EROD activity in eels caught from the Elbe estuary to 600 km upstream. Since the eel’s onset of cessation of feeding is closely linked to maturation and migration, we propose bile pigments as new indicators contributing to identify the proportion of migratory eel, which is crucial information for eel management plans. We showed that PAH metabolites normalized to bile pigments as well as EROD could be used to describe the habitat quality and might be suitable parameters in search for suitable stocking habitats.  相似文献   
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Varis O  Keskinen M  Kummu M 《Ambio》2008,37(3):146-149
The Mekong region is undergoing rapid transitions, socially, economically, and environmentally. Economies are stabilizing after the political turbulence of the last several decades, and development pressures as well as ambitions are vast. Water is related to these social, economic, and environmental changes in many ways and in a very profound manner. This article summarizes the approach and major conclusions of the research project title "Integrated Water Resources Management (IWRM) on the Mekong River." The concept of IWRM is elaborated in the setting of these major transitions, and the roles of academic research and education are highlighted.  相似文献   
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The amount of biosolids recycled in agriculture has steadily increased during the last decades. However, few models are available to predict the accompanying risks, mainly due to the presence of trace element and organic contaminants, and benefits for soil fertility of their application. This paper deals with using data mining to assess the benefits and risks of biosolids application in agriculture. The analyzed data come from a 10-yr field experiment in northeast France focusing on the effects of biosolid application and mineral fertilization on soil fertility and contamination. Biosolids were applied at agriculturally recommended rates. Biosolids had a significant effect on soil fertility, causing in particular a persistent increase in plant-available phosphorus (P) relative to plots receiving mineral fertilizer. However, soil fertility at seeding and crop management method had greater effects than biosolid application on soil fertility at harvest, especially soil nitrogen (N) content. Levels of trace elements and organic contaminants in soils remained below legal threshold values. Levels of extractable metals correlated more strongly than total metal levels with other factors. Levels of organic contaminants, particularly polycyclic aromatic hydrocarbons, were linked to total metal levels in biosolids and treated soil. This study confirmed that biosolid application at rates recommended for agriculture is a safe option for increasing soil fertility. However, the quality of the biosolids selected has to be taken into account. The results also indicate the power of data mining in examining links between parameters in complex data sets.  相似文献   
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The increasing availability of spatial data inspires the exploration of previously less-studied, yet regionally and nationally important areas, such as the Irrawaddy and Salween River Basins in Southeast Asia. This article documents our experience using global datasets to create environmental basin profiles in these two basins. Our approach draws on the concepts of freshwater vulnerability assessments that guided the selection of indicators. Data on land use, population distribution and fertilizer load were used. The unit of analysis was chosen to distinguish areas with similar bio-geographical characteristics, such as the critical delta areas. Results were further discussed for sub-areas that experience relatively the most pressure in terms of examined indicators within the studied area. The river mouths of both rivers had the most intensive land use and high population density. They are also home to important ecosystems and are sensitive to changes in upstream areas. Our study presents a concise and spatially distributed view of the environmental basin profiles of the Irrawaddy and Salween River Basins. The analysis also provides some interesting methodological insights about the potential of public macro-scale datasets for environmental assessment. The spatial approach allowed the analysis of different indicators, providing a platform for data integration as well as a visually powerful overview of the study area. Yet, the use of macro-scale datasets entails challenges. Despite improvements, the assessment process tends to be driven by the availability and quality of data, rather than by the actual research and management needs. The greatest utility of macro-scale datasets lies—at least in data-poor areas—in larger scale comparative analyses between the basins and their different sub-areas.  相似文献   
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After the signing of the ICZM Protocol in the Mediterranean (Madrid, 21 January 2008) its implementation became the main focus of interest for the future. Several obstacles on the way to implementation are briefly analysed, starting with the ratification process, the competence for the implementation and the availability of financial resources to put the Protocol requirements in place. A list of mitigation actions is proposed in order to overcome these obstacles. The ways in which the Centre responsible for assisting the countries can implement this legal instrument (i.e. PAP/RAC) is elaborated in the second part of the paper. This includes the preparation of a stocktaking report to allow for defining the starting point for ICZM in the Mediterranean, elaboration of an explanatory guide of the text of the Protocol, as well as guidelines for the definition of a coastal setback. Equally important is awareness-raising and training for the implementation of the Protocol.  相似文献   
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