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991.
992.
区域水污染源在线监测监控系统的建立及其运维保障 总被引:1,自引:0,他引:1
建立区域水污染源在线监测监控系统在实施区域水污染源总量控制中具有重要作用,区域监控中心与各污染源在线监测站点组成了系统的基本构架,对系统进行有效维护,建立良好的运维保障体系,是建设区域水污染源在线监测监控系统并保障其正常运行的基本保证。 相似文献
993.
WANG Hailin ZHUANG Yahui WANG Ying SUN Yele YUAN Hui ZHUANG Guoshun HAO Zhengping 《环境科学学报(英文版)》2008,20(11):1323-1327
During 2001-2006,PM2.5 (particle matter with aerodynamic diameter less than 2.5 microns) and PM10 (particle matter with aerodynamic diameter less than 10 microns) were collected at the Beijng Normal University (BNU) site,China,and in 2006,at a background site in Duolun (DL).The long-term monitoring data of elements,ions,and black carbon showed that the major constituents of PM2.5 were black carbon (BC) crustal elements,nitrates,ammonium salts,and sulfates.These five major components accounted for 20%-80% of... 相似文献
994.
995.
本文把环境经济学中的有关原理和方法引入工业污染源监测工作中。详细介绍了产品物料投入—转化—产出全平衡模型的建立;并在此基础上进行工业污染源工艺剖析和有关计算,确定出工业污染源监测点位的布设和监测频率 相似文献
996.
J.C. Doornkamp 《Journal of environmental management》1998,52(4):327-333
A review of the difficulties associated with the definition of coastal flood frequencies and magnitudes leads to a recognition that there is considerable doubt in many parts of the world as to the precise nature of this particular hazard. Similarly, a review of the sea-level measurements that have been used to indicate a response to global warming shows that there is uncertainty about the amount of other controlling influences. What is clear, however, are that past management decisions about human endeavours in the coastal zone (including flood defences, occupance of flood-prone lands, extraction of ground water and natural gas) have had an impact on relative land and sea levels and have done more to increase the risk of coastal flooding than can be assigned so far to global warming. In addition, these changes induced by human activity may render inappropriate calculations of coastal-flood frequencies based on historical records since the latter relate to a period of time when the controls on flooding may have been very different. 相似文献
997.
O. Thas L. Van Vooren J. P. Ottoy 《Journal of the American Water Resources Association》1998,34(2):347-357
ABSTRACT: In this paper four nonparametric tests for monotonic trend detection are compared with respect to their power and accuracy. The importance of comparing powers at equal empirical significance levels rather than nominal levels is stressed. Therefore, an appropriate graphical method is presented. The effect of the sampling frequency is also assessed using Monte Carlo simulations and a trajectory representation that visualizes the dynamics of the trade-off between the type I and type II errors. These methods are applied to compare four nonparametrical tests (seasonal Mann. Kendall, modified seasonal Mann-Kendall, covariance eigenvalue and covariance inversion) under several conditions. It is concluded with respect to the power that it is not worthwhile for the modified seasonal Mann-Kendall test applied to the AR(1) process considered in this paper to increase the sampling frequency from monthly to biweekly for detecting a monotonic trend of 5 percent, 10 percent, or 15 percent of the process variance. Under these conditions the seasonal Mann-Kendall test is highly liberal, while the covariance inversion and the covariance eigenvalue test are conservative. This research is situated in the development of an efficient sampling design for the Flemish water quality monitoring network. 相似文献
998.
The purpose of this paper is to present and compare two independent sets of environmental gamma spectrometry measurements of137 Cs collected nearly 14 years apart. One set of data was collected in 1978 by a contractor of the U.S. Department of Energy during an aerial radiological survey of the northern atolls of the Marshall Islands. That program used helicopter mounted sodium-iodide scintillation detectors; measurements were made from an altitude of 38 m. The second measurement program was conducted from early 1990 through late 1994 by the Republic of the Marshall Islands Government in a survey of the entire nation. This latter program used ground level in situ gamma spectrometry with high-purity germanium detectors. In this comparison, we highlight differences between the findings of the two studies and probable reasons for those differences, though we also discuss the effectiveness of the two techniques for monitoring the ionizing radiation environment. In the comparison of exposure rates from 137Cs, fair agreement was noted after accounting for radioactive decay during the intervening years. Though the distributions were statistically different over their entire range, they were nearly identical above 1 R h-1. There was considerable difference in the estimates of137 Cs inventory; the difference was greater at low activity levels with the NaI measurements consistently larger than the in situ measurements. Reasons for this difference is attributed to three factors which differed between the two studies: (1) the assumed penetration of the cesium into the soil column, (2) the assumption of soil density, and (3) differences in the ability of the two different detector systems to reject interfering spectral contributions. Precise measurement of the lowest levels has implications for determining those atolls that exceeded the deposition of 137Cs from global fallout. This issue is discussed in addition to a comparison of the findings from the two measurement programs. 相似文献
999.
Veronique Garny Andre Lecloux Roger Papp 《Environmental monitoring and assessment》1998,53(3):395-399
A voluntary programme on risk assessment for chlorinated chemicals was initiated by Euro Chlor (the European Chlorine Producers Federation). The study was targeted on the marine environment, starting with the North Sea, and the methodology used was based on the European Union risk assessment principles. Details of the method used are described in this paper. A first set of five compounds is published in this special issue: chloroform, 1,2-dichloroethane, 1,1,2-trichloroethane, trichloroethylene, tetrachloroethylene. 相似文献
1000.
船舶溢油卫星监测与信息高速公路 总被引:5,自引:0,他引:5
溢油污染严重威胁海洋环境,建立常规化的卫星遥感监测系统并纳入信息高速公路计划是非常必要的。本文在考察了其它船舶溢油监测方法的基础上,提出了利用卫星遥感监测溢油的可能性及在我国目前国力条件下利用卫星遥感方法实现常规监测的可行性,并探讨了在3S技术支持下建立常规化的船舶溢油卫星遥感监测系统的基本问题。 相似文献