PARAMETRIC/NONPARAMETRIC MIXTURE DENSITY ESTIMATION WITH APPLICATION TO FLOOD-FREQUENCY ANALYSIS1

Much attention has been invested in the model choice problem for peak annual flows, in the context of flood frequency analysis. The authors would sidestep this dilemma through non-parametric density estimation methodology, but recognize that the standard nonparametric estimators preclude the use of prior information and related data, and furthermore have virtually no tail at all. Here we offer a remedy for these inadequacies by introducing an estimator which mixes parametric and nonparametric density estimates. We prove that our mixture rule is consistent. By this procedure, we do allow incorporation of prior information, experience, and regional data information, but nevertheless provide a safeguard against incorrect model choice.     

Culture and the environment in Britain

The British pride themselves on their long tradition of landscape management rooted in the aristocratic and landowning classes of the 18th and 19th centuries. The British also emphasize that the rise of modern pollution control began in the Victorian industrial era with the emergence of the national Inspectorates and the local Commissioners of Sewers. All these traditions are rooted in British social history, which was heavily influenced by class, power, and the changing shape of industrial and agricultural development. In modern Britain, affected by industrial recession, where concern over jobs and growth appears to dominate public and political attention, as well as public spending cuts that sap the morale and effectiveness of the major regulatory agencies, attitudes toward, and the execution of, environmental protection are undergoing a subtle but profound revolution. It is slowly but agonizingly being recognized that economic growth and social well-being cannot be disconnected from environmental processes and the limits these impose on management and technological intervention. A 21st century Britain will have to integrate conservation with development in order to survive.     

REGIONAL RAINFALL INTENSITY-DURATION-FREQUENCY CURVES FOR PENNSYLVANIA1

ABSTRACT: A statistical analysis of all available continuous hourly and 15-minute duration rainfall records for Pennsylvania was performed to develop an updated procedure to estimate design storms. As a resuit of this study, Pennsylvania was divided into five homogeneous rainfall regions and a set of rainfall intensity-duration curves developed for each region, for return periods of 1 to 100 years and durations ranging from 5 minutes to 24 hours. The PDT-IDF curves were judged to be a better representation of Pennsylvania rainfall than the nationwide TP-40 maps, particularly for storm events of 10-years and lower return periods. The average time distribution of 24-hour storms in Pennsylvania was found to be well represented by the SCS Type II distribution. The Corps of Engineers SPS 24-hour distribution was found to differ appreciably from both the SCS Type H and the Pennsylvania 24-hour storm distribution. For storm durations between 15 and 90 minutes the standard Yarnell intensity-duration curves closely resemble Pennsylvania storm distributions.     

中央广播电视发射塔环境电磁辐射测试研究

对发射７套电视节目和５套调频节目，发射总功率２４０ＫＷ的中央广播电视塔电磁辐射场强监测结果表明：（１）由于节目频率不同，发射机功率及发射天线形式、高度、增益不同，电磁波到达地面最大场强值的距离是不同的；在近距离内高层建筑各层所接收到的场强大小也是不同的。（２）电视与调频信号在近距离昼夜电平无明显变化。（３）电视塔周围２０００米内环境综合场强最大值为２８４～３２８μＷ／ｃｍ２，所有环境测量值均小于公众导出限值４０μＷ／ｃｍ２。     

GC／MS对一起死鱼事故的监测分析

利用ＧＣ／ＭＳ对一起死鱼事故中的鱼塘水样，鱼肉样进行了监测，检出的６个化合物均与某化工厂的原料，产品，中间体及其衍生物相吻合，迅速判定了污染事故的责任者。     

水体有毒有机污染研究

对有毒有机污染物的主要种类,实际的检出水平,健康影响评价、污染处理技术进行了简要介绍,在此基础上对管理对策进行了探讨。     

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。     

天津市空气质量时间变化规律及相关性分析

按时间段对天津市环境空气监测国控点2005年的SO2、NO2和PM10监测数据进行统计分析,SO2、NO2和PM10时间变化规律呈现典型的双峰双谷型,SO2、NO2污染呈现明显的季节性,而PM10污染相对稳定。对SO2、NO2和PM10在全年、采暖期和非采暖期的时间变化进行相关性分析,结果表明,除了非采暖期NO2和SO2相关性不显著外,其它均存在较强的相关性。     

用热释光剂量计对哈密地区环境天然贯穿辐射水平调查

用国产ETLD-80型热释光环境剂量计调查了哈密地区环境天然贯穿辐射水平.结果表明,哈密地区室外、室内宇宙射线电离辐射空气吸收剂量率分别为(3.7±0.3 )、(3.3±0.3)×10~(-8)Gy/h,人口加权平均值分别为3.2和2.8×10~(-8)Gy/h.地球γ辐射空气吸收剂量率分别为(5.8±0.9)、(7.7±1.2)×10~(-8)Gy/h,人口加权平均值分别为5.0和6.6×10~(-8)Gy/h.天然贯穿辐射所致居民有效剂量当量为71.7μSv/a(宇宙辐射298μSv/a,地球γ辐射419μSv/a).     

环境在线监测监控管理与发布系统

阐述了省级环境在线监测监控管理与发布系统的组成及功能特点,介绍了采用GPRS无线数据传输方式,对水、气、污染源等环境在线监测自动化系统进行数据采集、统计与GIS发布的实现方式,指出其具有传输速率高、延时小、实时性强、建设方便、费用低廉等显著优点。