降雨影响噪声自动监测数据的有效性判定分析

选取北京市近5年夏半年（4—9月）夜间的降雨数据及相关噪声自动监测小时等效声级,对小时雨量与噪声自动监测数据进行数学统计分析,找出影响噪声监测数据的小时雨量值及不同声级受雨噪声影响的雨量限值,作为降雨对噪声自动监测小时等效声级的有效性判定条件。     

完善突发环境事件应急管理体系的几点建议

分析了我国突发环境事件中以预案、法制、体制和机制为核心的应急管理体系现状,分析了在"一案三制"体系建设中存在的问题,并对"一案三制"的应急管理体系建设提出了相关建议。     

湖北农村降水中SO_4~(2-)浓度变化研究

在湖北农村 10个地点 ,利用澳大利亚集雨器自 1996年 1月至 1998年 6月 ,按季度采集大气降水样品测定SO2 - 4浓度 ,并对数据进行统计分析。研究结果表明 ,各地 1997年降水中SO2 - 4浓度年均值比 1996年显著升高 ;大多数地点 1996、1997、1998年 1季度和 2季度降水中SO2 - 4浓度呈逐年升高趋势 ;大多数地点每年 1、4季度降水中SO2 - 4浓度高 ,2、3季度降水中SO2 - 4浓度低 ,说明湖北农村降水中的硫对秋冬作物影响比对春夏作物影响大 ;湖北农村降水中SO2 - 4浓度近两年不仅有时间变化规律 ,而且同一季度内的地区差异也很明显 ,在 1996年和 1997年 8个季度 10个点的降水SO2 - 4浓度最大值中 ,有 4个最大值出现在襄樊 ,它是目前湖北继宜昌市区、恩施市区之后又一个酸雨发展较快的地区     

ACCOUNTING FOR DISCREPANCIES IN PAN EVAPORATION CALCULATIONS1

ABSTRACT: Four experiments were made to document and account for differences in evaporation data that were calculated using pans equipped with float-activated recorders and pans with hook gauge/rain gauge instrumentation. Paired in-pan comparisons indicated that evaporation differences were not due to the technique of measuring water level within the pan. Also, the recorder float-lag did not account for the differences. By sampling rainfall events, it was found that evaporation pans and standard (8 in. orifice) rain gauges record significantly different amounts of rain, which results in differences in calculated evaporation on rainy days. Monitoring networks with evaporation pans should have uniform instrumentation that accurately records rainfall into the pans for consistent results.     

STATISTICAL CONSIDERATIONS ON THE RANDOMNESS OF ANNUAL MAXIMUM DAILY RAINFALL1

ABSTRACT: Annual maximum daily rainfall data from nine stations throughout the southern slopes of the Eastern Italian Alps with record length of 67–68 years have been analyzed with the aim of verifying if their internal structure justifies the assumption of independence and identical distribution, or the “White noise hypothesis.” The approach is to consider the hypothesis H₀ of white noise as the intersection of several sub-hypotheses, each concerning one of the characteristics of a white noise process. To this end the nine series were subjected to various statistical tests regarding randomness, independence, change-points, and predictability. The results are examined first individually and then globally. They indicate that in eight of the nine considered time series the “white noise hypothesis” was rejected.     

INFILTRATION EVALUATION OF FOUR MECHANICAL RAINFALL SIMULATION TECHNIQUES IN SIERRA NEVADA WATERSHEDS1

ABSTRACT: Little quantitative site-specific infiltration, runoff and sediment transport data for Tahoe Basin soils under varying storm events or stage of development are available. Modular (Ml), F-type (M2), Impact nozzle (M3), and Impact-Fan nozzle (M4) rainfall simulators were evaluated as to their practicality and ability to characterize infiltration for the Cagwin Soil Series within the Tahoe Basin. Three slope (0–15,15–30, >30%) and four plot conditions (natural with duff [P1], natural without duff [P2], disturbed without duff [P3], and disturbed with duff [P4]) were studied. The measured data were incorporated into a modified Philip's infiltration model and multiple non-linear regression analyses were used to examine relationships between method, slope, plot condition, and infiltration characteristics.^t Simulation methods Ml and M4 produced statistically similar (P=0.01) infiltration data, as did M2 and M3 which produced lower infiltration rates. All were found suitable for use in Sierra Nevada watersheds. Ml was considered most practical. Slope had negligible effect on infiltration. The plot condition was found to significantly influence infiltration, and the effect of each plot condition was significantly different. Final infiltration rates ranged from 4.7 to 6.2 cm/hr. Thus, the Cagwin soil demonstrated moderate to high infiltration rates even when exposed to extreme storm conditions (8–10 cm/hr).     

HYDROLOGIC RESPONSES OF AN AGRICULTURAL WATERSHED TO VARIOUS HYDROLOGIC AND MANAGEMENT CONDITIONS1

ABSTRACT: The hydrologic responses from an agricultural watershed in southeast Nebraska were investigated under an array of physiographic, hydrologic, meteorologic, and management conditions. For analytical purposes, the hydrologic responses were narrowed to include only runoff and sediment yield. The study was performed by utilizing the ANSWERS (Areal Nonpoint Source Watershed Environment Response Simulation) hydrologic-simulation model. Results of this study indicate that, generally, nonstructural (agronomic) Best Management Practices (BMPs) have a more significant impact in controlling erosion and nonpoint-source pollution than structurally oriented BMPs. The percentage of reduction in average soil loss as a result of changing tilage systems from conventional to chisel plow was in the mid-40s. The corresponding percentages of reduction in sediment yield from the watershed under minimum tillage and no-till systems were in the mid-60s and mid-80s, respectively. The impact of these management strategies on runoff varied considerably. That is primarily based on the watershed's antecedent soil moisture condition, land use, and the growth stage of crops. Generally, an intense, short, thunderstorm type of rainfall event had more relative impact on runoff, and therefore sediment yield than a long, gentle, and steady event.     

中国高温下臭氧抑制事件的时空特征及其影响因素

温度是影响臭氧生成的关键气象因子，通常情况下，臭氧和温度呈显著正相关关系，即臭氧浓度随着温度的升高而上升.然而这种关系在极高温时可能发生改变，当温度超过某个阈值时，臭氧浓度呈下降趋势，称为臭氧抑制事件.臭氧抑制事件导致气候变化背景下未来空气质量预测具有更多不确定性.基于全国空气质量监测数据和气象观测数据，采用Z检验方法，系统分析了2013~2020年暖季（4~9月）我国臭氧抑制事件频次及临界温度（T_x）的时空特征，并分析了引起臭氧抑制事件发生的可能影响因素.结果表明，2013~2020年暖季，我国约有18%的站点发生臭氧抑制事件，发生频率较高的站点主要分布在四川、新疆、陕西等中国中西部地区，平均达到10次·a^-1.发生臭氧抑制事件的T_x介于19.2~39.3℃，且大多数站点的T_x呈逐年上升趋势；T_x高值区主要分布在四川、重庆、湖南和湖北等中西部地区，而T_x低值区则集中在青藏高原一带.与T_x年变化趋势相反，2013~2020年暖季京津冀的臭氧抑制事件频率显著下降，汾渭平原、长三角和成渝地区的臭氧抑制事件频率呈"升高-降低-升高"变化特征.珠三角城市群极端高温抑制臭氧的作用最显著.此外，臭氧前体物（例如NO₂）和气象条件（风速、风向）是导致臭氧抑制事件的可能原因.     

城市降雨径流污染及最佳治理方案探讨

城市降雨径流污染已经成为非点源污染的一个新亮点,随着城市工业废水和生活污水等点源治理力度的加大,城市降雨径流污染问题将越来越突出.文章系统阐述了城市降雨径流污染的过程、污染类型及来源、污染物特征,对各种具体的城市降雨径流污染控制与治理技术进行了总结,并着重介绍了城市降雨径流污染最佳管理措施,还提出了实施城市降雨径流污染治理的具体对策和指导思想.     

高速公路降雨径流污染特征及其污染控制

随着高速公路的快速发展,路面降雨径流污染引起了越来越多的关注.从高速公路路面雨水径流中污染物成分及其影响因素、径流污染迁移模型和径流污染物对受纳水体水质的影响等方面,对路面降雨径流污染特征进行了综述,并从工程和非工程措施两方面比较了目前高速公路路面降雨径流污染治理措施的特点和适用条件,最后提出了进一步研究的建议,希望为有关方面的研究提供借鉴.