This study presents a methodology for siting municipal solid waste landfills, coupling geographic information systems (GIS),
fuzzy logic, and multicriteria evaluation techniques. Both exclusionary and non-exclusionary criteria are used. Factors, i.e.,
non-exclusionary criteria, are divided in two distinct groups which do not have the same level of trade off. The first group
comprises factors related to the physical environment, which cannot be expressed in terms of monetary cost and, therefore,
they do not easily trade off. The second group includes those factors related to human activities, i.e., socioeconomic factors,
which can be expressed as financial cost, thus showing a high level of trade off. GIS are used for geographic data acquisition
and processing. The analytical hierarchy process (AHP) is the multicriteria evaluation technique used, enhanced with fuzzy
factor standardization. Besides assigning weights to factors through the AHP, control over the level of risk and trade off
in the siting process is achieved through a second set of weights, i.e., order weights, applied to factors in each factor
group, on a pixel-by-pixel basis, thus taking into account the local site characteristics. The method has been applied to
Evros prefecture (NE Greece), an area of approximately 4,000 km2. The siting methodology results in two intermediate suitability maps, one related to environmental and the other to socioeconomic
criteria. Combination of the two intermediate maps results in the final composite suitability map for landfill siting. 相似文献
Nitrogen (N) cycling and respiration rates were measured in sediment columns packed with southeastern United States continental shelf sands, with high permeability (4.66×10−11 m2) and low organic carbon (0.05%) and nitrogen (0.008%). To simulate porewater advection, natural shelf seawater was pumped through columns of different lengths to achieve fluid residence times of approximately 3, 6, and 12 h. Experiments were conducted seasonally at in situ temperature. Fluid flow was uniform in nearly all columns, with minimal dead zones and channeling. Significant respiration (O2 consumption and ∑CO2 production) occurred in all columns, with highest respiration rates in summer. Most (78–100%) remineralized N was released as N2 in the majority of cases, including columns with oxic porewater throughout, with only a small fraction released as NO3− from some oxic columns. A rate of 0.84–4.83×1010 mol N yr−1, equivalent to 1.06–6.09×10−6 mmol N cm−2 h−1, was calculated for benthic N2 production in the South Atlantic Bight, which can account for a large fraction of new N inputs to this shelf region. Metal and sulfate reduction occurred in long residence time columns with anoxic outflow in summer and fall, when respiration rates were highest. Because permeable sediments dominate continental shelves, N2 production in high permeability coastal sediments may play an important role in the global N cycle. 相似文献
Extensive pumping to extract water from Mexico City's subsoil has caused regional sinking. Water pumping produces regional consolidation which increases effective stresses acting on the subsoil modifying its static and dynamic properties. As the soil properties change, so does their dynamic response. Approximate expressions to estimate the future changes in soil properties are proposed. Also, this paper puts forth new evidence to illustrate these changes and presents estimates of future settlements in central Mexico City, using a soil consolidation model that overcomes some of the limitations of Terzaghi's theory. Results of an analysis to estimate the effects of the evolution of the subsoil's dynamic properties are illustrated by means of seismic analyses performed on a couple of sites in an old lake bed in Mexico City. 相似文献
Limiting global warming to ‘well below’ 2°C above pre-industrial levels and pursuing efforts to limit the temperature increase even further to 1.5°C is an integral part of the 2015 Paris Agreement. To achieve these aims, cumulative global carbon emissions after 2016 should not exceed 940 – 390?Gt of CO2 (for the 2°C target) and 167 – ?48?Gt of CO2 (for the 1.5°C target) by the end of the century. This paper analyses the EU’s cumulative carbon emissions in different models and scenarios (global models, EU-focused models and national carbon mitigation scenarios). Due to the higher reductions in energy use and carbon intensity of the end-use sectors in the national scenarios, we identify an additional mitigation potential of 26–37 Gt cumulative CO2 emissions up to 2050 compared to what is currently included in global or EU scenarios. These additional reductions could help to both reduce the need for carbon dioxide removals and bring cumulative emissions in global and EU scenarios in line with a fairness-based domestic EU budget for a 2°C target, while still remaining way above the budget for 1.5°C.Key policy insights
Models used for policy advice such as global integrated assessment models or EU models fail to consider certain mitigation potential available at the level of sectors.
Global and EU models assume significant levels of CO2 emission reductions from carbon capture and storage to reach the 1.5°C target but also to reach the 2°C target.
Global and EU model scenarios are not compatible with a fair domestic EU share in the global carbon budget either for 2°C or for 1.5°C.
Integrating additional sectoral mitigation potential from detailed national models can help bring down cumulative emissions in global and EU models to a level comparable to a fairness-based domestic EU share compatible with the 2°C target, but not the 1.5°C aspiration.
Using hydro-meteorological time series of 50 years and in situ measurements, the dominant runoff processes in perennial Andean headwater catchments in Chile were determined using the hydrological model HBV light. First, cluster analysis was used to identify dry, wet and intermediate years. From these, sub-periods were identified with contrasting seasonal climatic influences on streamflow. By calibrating the model across different periods, impacts on model performance, parameter sensitivity and identifiability were investigated, providing insights into differences in hydrological processes. The modelling approach suggested that, independently of a dry or wet period of calibration, the streamflow response is mostly consistent with flux from groundwater storage, while only a small fraction comes from direct routing of snowmelt. The variation of model parameters, such as the groundwater rate coefficient, was found to be consistent with differing recharge in wet and dry years. The resulting snowmelt–groundwater model is a realistic hypothesis of the hydrological operation of such complex, data scarce and semi-arid Andean catchments. This model may also be a useful tool for predictions of seasonal water availability and a basis for further field studies. 相似文献
ABSTRACTSubmarine canyons play an important role in the regional distribution, abundance and dispersal of marine biota and are increasingly being recognised as geomorphic features of high conservation significance along Australia’s continental margin. Certain canyons have been described as foraging ‘hotspots’ attributable to the high abundance of apex cetacean species aggregating in these areas. Anecdotal evidence of large seasonal aggregations of killer whales in the Bremer Canyon, south-west Australia, has attracted significant research attention in the last decade. To identify important environmental drivers influencing aggregation patterns, a predictive spatial habitat model using the Maxent model was developed based on presence-only whale sighting data. In addition, remotely sensed sea surface temperature and chlorophyll-a concentrations were assessed to investigate the spatio-temporal variation in sea surface conditions. Habitat preference was predicted in areas between canyon heads, with the most influential predictor variables being depth and distance from the continental shelf break. Analysis of remote-sensing data highlighted low localised variability in surface waters and illustrated the seasonal trends of the Leeuwin Current. This study demonstrates the influence of bathymetry and submarine geomorphology on enhanced cetacean abundance and highlights the need for recognition of this potential foraging area in marine reserve planning. 相似文献
ABSTRACTResearch on the financialisation of land and agribusiness has highlighted major shifts in agri-food systems globally. Yet these accounts tend to focus on the activities of financial actors, and few take seriously the role of farmers in negotiating investments in land and agribusiness. Farmers in the global North may be well placed to benefit from partnerships with financial investors, although little is known about the way that such partnerships are formed. Australian studies of farmer agency have been productive in examining farm family entrepreneurs and globally engaged farmers who work beyond the farm gate to organise supply chains. This paper adds to these studies by providing insights about a capitalising farm family entrepreneur, who successfully negotiated and entered into a direct equity partnership with a large foreign pension fund. Several observations are significant: the exceptional skill, time and expense required to negotiate these partnerships; the role of consultants and non-human actors in structuring them; and the spatially- and temporally divergent farm development practices that are enabled by a shift from debt to equity financing. These observations are indicative of a new adaptive strategy of family farmers to shifting financial landscapes and of emergent family, corporate, and financial farm hybridity. 相似文献