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891.
在建立城市污水处理厂毒物归宿模型的基础上,继续探讨了固液相吸附分配系数Kp,生物降解速率系数Kb,挥发及吹脱速率系数KvKst等模型参数的估计方法,并就模型的检验,模拟及其在风险评价中的应用作了案例研究。 相似文献
892.
Restoration ecology of riverine wetlands: I. A scientific base 总被引:10,自引:0,他引:10
893.
Sound ecosystem management meshes socioeconomic attitudes and values with sustainable natural resource practices. Adaptive management is a model for guiding natural resource managers in this process. Ecosystems and the societies that use them are continually evolving. Therefore, managers must be flexible and adaptable in the face of uncertainty and lack of knowledge. To couple good science to management, it is important to develop goals, models, and hypotheses that allow us to systematically learn as we manage. Goals and models guide the development and implementation of management practices. The need to evaluate models and test hypotheses mandates monitoring, which feeds into a continuous cycle of goal and model reformulation. This paper reviews the process of adaptive management and describes how it is being applied to oak/pine savanna restoration at Necedah National Wildlife Refuge as an illustration. Our aim is to help managers design their own adaptive management models for successful ecosystem management. 相似文献
894.
用示波极谱法对酚类化合物进行分析,方法的线性范围在3.0×10 ̄(-5)~8.0×10 ̄(-3)mg/L之间,最低检出限为6.0×10 ̄(-6)mg/L,浓度为0.26×10 ̄(-2)~0.52mg/L时的相对标准偏差为1.8%~4.0%,浓度为0.3×10 ̄(-2)~0.51mg/L时的回收率为95.0%~102.1%,其结果与4-氨基胺替比林分光光度法相一致。 相似文献
895.
Peter N. Duinker 《Environmental management》1989,13(6):797-805
The premise that, strictly speaking, impact monitoring is impossible, is presented and discussed It is shown that a wide range of published objectives for environmental effects monitoring can be seen as special cases of the basic goal of reducing uncertainty in predictions. Monitoring in environmental-impact situations can only be used as a check on one of the two time series required to define impact. Four approaches to generating the other time series required in the difference calculation of impact are discussed, with the conclusion that the best approach relies on process-based simulation models. Impact analysts are encouraged to consider carefully what can and cannot actually be accomplished with environmental monitoring to assist impact detection. 相似文献
896.
897.
Adaptation pathways approaches support long-term planning under uncertainty. The use of adaptation pathways implies a systematic monitoring effort to inform future adaptation decisions. Such monitoring should feed into a long-term collaborative learning process between multiple actors at various levels. This raises questions about who should monitor what, when and for whom. We formulate an approach that helps to address these questions, developed around the conceptual core offered by adaptive policy pathways methods and their notion of signposts and triggers. This is embedded in a wider approach that revisits the critical assumptions in underlying basic policies, looks forward to future adaptation decisions, and incorporates reciprocity in the organization of monitoring and evaluation. The usefulness and practical feasibility of the approach is studied for a case of the Delta Programme in the Netherlands, which incorporated adaptation pathways in its planning approach called adaptive delta management. The case results suggest that our approach adds value to existing monitoring practices. They further show that different types of signposts exist. Technical signposts, in particular, need to be distinguished from political ones, and require different learning processes with different types of actors. 相似文献
898.
测量机器人在地壳形变监测中的应用 总被引:2,自引:0,他引:2
本文介绍了以全自动化全站仪(Leica TCA2003)为基础组成的新型地震形变监测系统。并分别从仪器的功能、精度以及与原有测量模式相比其效率、精度、和代替原来测量模式可行性方面作了介绍。为地震系统新仪器的引入提供一个参考。 相似文献
899.
A two-dimensional simulation model of phosphorus uptake including crop growth and P-response 总被引:2,自引:0,他引:2
Alain Mollier Peter De Willigen Marius Heinen Christian Morel Andr Schneider Sylvain Pellerin 《Ecological modelling》2008,210(4):453-464
Modelling nutrient uptake by crops implies considering and integrating the processes controlling the soil nutrient supply, the uptake by the root system and relationships between the crop growth response and the amount of nutrient absorbed. We developed a model that integrates both dynamics of maize growth and phosphorus (P) uptake. The crop part of the model was derived from Monteith's model. A complete regulation of P-uptake by the roots according to crop P-demand and soil P-supply was assumed. The soil P-supply to the roots was calculated using a diffusion equation and assuming that roots behave as zero-sinks. The actual P-uptake and crop growth were calculated at each time step by comparing phosphate and carbohydrate supply–demand ratios. Model calculations for P-uptake and crop growth were compared to field measurements on a long term P-fertilization trial. Three P-fertilization regimes (no P-fertilization, 42.8 kg P ha−1 year−1 and 94.3 kg P ha−1 year−1) have led to a range of P-supply. Our model correctly simulated both the crop development and growth for all P-treatments. P-uptake was correctly predicted for the two non-limiting P-treatments. Nevertheless, for the limiting P-treatment, P-uptake was correctly predicted during the early period of growth but it was underestimated at the last sampling date (61 day after sowing). Several arguments for under-prediction were considered. However, most of them cannot explain the observed magnitude in discrepancy. The most likely reason might be the fact that biomass allocation between shoot and root must be modelled more precisely. Despite this mismatch, the model appears to provide realistic simulations of the soil–plant dynamic of P in field conditions. 相似文献
900.
A comparison of mussels (Perna viridis) and semi-permeable membrane devices (SPMDs) was carried out at five sites, representing a gradient of contaminant concentrations, in Hong Kong coastal waters. Mussels, originally collected from a “clean” location, were deployed along with SPMDs at each site for 30 days. Analyses for chlorinated pesticides and polychlorinated biphenyls (PCBs) indicated that SPMDs have potential as monitoring tools, and to some extent can overcome the problems associated with mussels, such as natural variability, differing age, sex, and physical condition. However, in most cases, SPMDs failed to rank the sites in the same order as mussels in terms of contaminant concentrations. Nonetheless, in localities where mussels cannot survive – as shown at Kwun Tong in the present experiment – SPMDs may be valuable in providing an indication of potentially bio-available lipophilic pollutants. 相似文献