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251.
Stephen J. Ventura Kyehyun Kim 《Journal of the American Water Resources Association》1993,29(2):189-198
ABSTRACT: A geographic information system (GIS) was a useful aid in the assessment of urban nonpoint source pollution and the development of a pollution control strategy. The GIS was used for data integration and display, and to provide data for a nonpoint source model. An empirical nonpoint source loading model driven by land use was used to estimate pollutant loadings of priority pollutants. Pollutant loadings were estimated at fine spatial resolution and aggregated to storm sewer drainage basins (sewersheds). Eleven sewersheds were generated from digital versions of sewer maps. The pollutant loadings of individual land use polygons, derived as the units of analysis from street blocks, were aggregated to get total pollutant loadings within each sewershed. Based on the model output, a critical sewershed was located. Pollutant loadings at major sewer junctions within the critical sewershed were estimated to develop a mitigation strategy. Two approaches based on the installation of wet ponds were investigated - a regional approach using one large wet pond at the major sewer outfall and a multisite approach using a number of smaller sites for each major sewer junction. Cost analyses showed that the regional approach would be more cost effective, though it would provide less pollution control. 相似文献
252.
The impact of long-range transport of yellow sand from Asian Continent to the Taipei Metropolitan Area (Taipei) not only deteriorates
air quality but also poses health risks to all, especially the children and the elderly. As such, it is important to assess
the enhancement of PM10 during yellow sand periods. In order to estimate PM10 enhancement, we adopted factor analysis to distinguish the yellow-sand (YS) periods from non-yellow-sand (NYS) periods based
on air quality monitoring records. Eight YS events were identified using factor analysis coupling with an independent validation
procedure by checking background site values, examining meteorological conditions, and modeling air mass trajectory from January
2001 to May 2001. The duration of each event varied from 11 to 132 h, which was identified from the time when the PM10 level was high, and the CO and NO
x
levels were low. Subsequently, we used the artificial neural network (ANN) to simulate local PM10 levels from related parameters including local gas pollutants and meteorological factors during the NYS periods. The PM10 enhancement during the YS periods is then calculated by subtracting the simulated PM10 from the observed PM10 levels. Based on our calculations, the PM10 enhancement in the maximum hour of each event ranged from 51 to 82%. Moreover, in the eight events identified in 2001, it
was estimated that a total amount of 7,210 tons of PM10 were transported by yellow sand to Taipei. Thus, in this study, we demonstrate that an integration of factor analysis with
ANN model could provide a very useful method in identifying YS periods and in determining PM10 enhancement caused by yellow sand. 相似文献
253.
上海城市风暴潮灾害及其预测 总被引:10,自引:2,他引:8
风暴潮是上海地区最主要的自然灾害之一。其特点一是大的风暴潮灾害都是由于台风影响造成的;二是重灾区主要发生在沿杭州湾、长江口地区和市区;三是随首防潮设施防御能力提高而减轻,随地面下沉面加重;四是随着长江口、黄浦江潮位的不断抬高,黄浦江中上游地区潮灾加重。因而,预测可能最高潮位,因害设防,对于防灾减灾具有实践意义。 相似文献
254.
255.
利用卫星监测资料、气象站的观测资料和北京市环境保护监测中心的PM10监测资料,通过对天气图进行分析,对发生在2000-11-01—07这一污染天气过程的成因和性质进行了解析。结果表明:在此期间PM10呈现准正态分布。污染过程由2个性质完全不同的阶段构成:第一阶段(11月1—3日)属于雾型污染,污染物是SO2,NO2等经过化学转化而成的硫酸盐和硝酸盐微粒;第二阶段(11月4—7日)属于沙尘型污染,该阶段的污染物是受上游沙尘天气影响而形成的黄土、浮尘。这2个阶段的气象过程及天气形势也完全不同,沙尘暴爆发前(前一阶段)的天气受均压场控制,呈现双层逆温结构,相对湿度较大;沙尘暴期间(后一阶段)的天气受高压前部西北气流控制,相对湿度大幅度下降,空气干燥度从地面到高空基本一致。 相似文献
256.
257.
利用河西走廊东部5个气象站1961─2007年逐月积雪深度、积雪日数和沙尘天气的常规观测资料,分析了河西走廊东部冬春季积雪深度、积雪日数和春夏季沙尘日数的时空变化特征,进而探讨河西走廊东部冬春季积雪与春夏季沙尘天气的关系. 结果表明:受海拔高度、地理位置以及天气系统等影响,河西走廊东部积雪从东南向西北递减,高海拔地区的积雪多于低海拔地区;沙尘日数从西北向东南递减,低海拔地区的沙尘日数明显多于高海拔地区. 河西走廊东部冬春季积雪与春夏季沙尘日数呈显著负相关. 积雪深度与沙尘日数的负相关性高于积雪日数与沙尘日数的负相关性;冬春季积雪对春季沙尘的影响大于对夏季沙尘的影响;山区积雪与沙尘日数的相关性高于平原区积雪与沙尘日数的相关性. 相似文献
258.
Sand and dust storms (SDS) are wind erosion events typically associated with dryland regions, although they can occur in most environments and their impacts are frequently experienced outside drylands because desert dust haze often is transported great distances. SDS represent hazards to society in numerous ways, yet they do not feature prominently in the disasters literature. This paper considers SDS in a hazard context by examining their ramifications in economic, physical, and social terms, with a focus on agriculture, health, transport, utilities, households, and the commercial and manufacturing sector. There are few assessments of the economic consequences of SDS and those studies that have been conducted lack consistency in data collection methods and analysis. SDS do not result in the significant damage to infrastructure usually associated with many disasters, but the cumulative effects on society can be significant because SDS occur more commonly than most other types of natural hazard. 相似文献
259.
Storm surge often is the most destructive consequence of hurricanes and tropical storms, causing significant economic damage and loss of life. Many coastal communities that are located in high‐risk areas vis‐à‐vis hurricanes and tropical storms are prepared for moderate (between six and eight feet) storm surges. Such preparation, though, is not commensurate with more severe, but less frequent, storm surges (greater than eight feet). These gaps in preparedness have serious implications for community resilience. This paper explores elements of the vulnerability and resilience of coastal communities during major storm surge events, drawing on Volusia County, Florida, United States, as a case study. It simulates the impacts of five hurricanes (Categories I–V) and their associated storm surges on local infrastructure systems, populations, and access to resources. The results suggest that Volusia County is subject to a ‘tipping point’ , where surge damage from Category IV storms is significantly greater than that from Category III and lower hurricanes. 相似文献
260.
Hydrology, roadway traffic conditions, and atmospheric deposition are three essential data categories for the planning and implementation of highway-runoff monitoring and characterization programs. Causal variables pertaining to each data category could be site specific but have been shown to correlate with runoff pollutant loads. These data categories were combined to derive statistical relationships for characterization and prioritization of the respective pollutant loads at highway runoff sites. Storm runoff data of total suspended solids (TSS), total dissolved solid (TDS), chemical oxygen demand (COD), total Kjeldahl nitrogen (TKN) and total phosphorus (TP) collected from three highway sites in Charlotte, North Carolina, USA, were used to illustrate the development of site-specific highway-runoff pollutant loading models. This unified methodology provides a basis for initial assessment of the pollutant-constituent loads from highway runoff using hydrologic component variables. Improved reliability is achievable when additional traffic and/or atmospheric component variables are incorporated into the basic hydrologic regression model. In addition, operational guidance is suggested for implementing highway-runoff monitoring programs that are subject to sampling and resources constraints. 相似文献