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Stanley A. Changnon Nancy E. Westcott 《Journal of the American Water Resources Association》2002,38(5):1467-1475
ABSTRACT: Operations of a dense raingage network in the Chicago area since 1989 provided data to assess the temporal and spatial distributions of heavy rainstorms. The 12‐year average was 4.4 storms per year, 40 percent more than in the 1948 to 1980 period, reflecting an ongoing Midwestern increase in heavy rains. The total rainfall from the 53 heavy rainstorms maximized over the city, reflecting previous observations that the influence of the city and Lake Michigan on the atmosphere causes an increase in heavy rains. Impacts from the record high number of eight storms in 2001 revealed that efforts to control flooding including the Deep Tunnel system, had reduced street and basement flooding in the moderate intensity storms, but the two most intense storms, each with 100‐year rainfall values, led to excessive flooding and a need to release flood waters into Lake Michigan. Results suggest continuing increases in the number of heavy rainstorms in future years, which has major implications for water managers in Chicago and elsewhere. 相似文献
246.
浅谈卧龙特区梯级电站建设对自然保护区的影响 总被引:2,自引:0,他引:2
根据笔者参加卧龙特区梯级电站规划中了解到的一些情况,首先阐述了保护区的自然环境和社会环境以及在此背景上造成的当前大熊猫的处境。接着分析了梯级电站建设可能带来的生态效益、经济效益和社会效益。同时,又估计到会带来的一些不利影响,重点是对大熊猫的生存环境方面。最后,从加强自然保护角度建议对方案中在核心区布置的一些梯级电站应持慎重态度,并提了几点保护措施。 相似文献
247.
江汉平原湖区农田防护林的小气候效应研究 总被引:5,自引:0,他引:5
在区域开发中,平原湖区的林业发展潜力很大,同时,湖区农田防护林的建设,也是促进生态平衡的一项重要措施,防护林能进一步改善湖区小气候环境,尤其对保障农业生产有着相当重要的意义。通过对江汉平原湖区的农田防护林网内的小气候效应温度,湿度,风速等要素的观测数据进行研究,我们得出的结果表明:江汉平原湖区农田林网的建设,除提供工农业生产所需的林木外,随着林木的增多,林网的完善,还可调节气候,保持水土,防风固沙 相似文献
248.
我国矿产资源利用的环境问题及对策 总被引:4,自引:0,他引:4
徐强 《中国人口.资源与环境》1995,5(1):33-37
矿产资源利用过程中靠成的环境问题是我国经济建设速发展所面临的一个现实问题本文全面地分析了矿产资源利用对环境影响的各个方面,分析了我国矿产资源环境问题的一些特点,提出了八个方面的对策建议。 相似文献
249.
Chung-Ming Liu 《Chemistry and Ecology》1996,12(1):147-161
In this paper, three sensitivity studies are designed to analyze the effect of the NMHC (Non-Methane HydroCarbon) composition, the aerosol back-scattering and the high chimney NOx emission to the photochemical prodution of ozone by using a one-dimensional photochemistry-diffusion model under a favourable meteorological condition. Measurements of the NMHC composition in Taipei indicated that the percentage of iso-butene, cis-2-butene, trans-2-butene and benzene in a unit volume was much higher than of those observed in other major cities. the high ratio of benzene was directly linked to its high percentage in gasoline. As to the unusually high amount of iso-butene, cis-2-butene and trans-2-butene, more researches are needed to identify their source. Concerns are raised as to how productive is NMHC composition is to the photochemical production of the surface ozone. A rough estimate shows that the total reactivity of the Taipei NMHC composition is about 1.21 × 10-9 cm3 s-1 which is 1.6 times that of the Los Angeles (LA) NMHC composition, while the simulated noon peak will be different by 28 ppbv, i.e. 18% more than that simulated with a LA composition.
Meanwhile, high aerosol loading is a serious problem in Taipei. the attenuation of the UV radiation by aerosols cannot be ignored. A numerical simulation shows that the noon ozone level will decrease from 178 to 141ppbv, i. e. about 21% reduction, with deterioration of the visual range from 85 to 5 km.
In the southern Taiwan, industry parks are mixed with the populated Kaohsiung city, hence the large emission of NOx from high chimneys cannot be ignored. in this study, NOx is assumed to be emitted in the layer between 235-460 m high with an emission rate of 0.05 or 0.145 ppbv/sec. the results show that the NOx emitted from the elevated stack lead to a considerable reduction of surface ozone. Such conclusion is obtained due to the fact that a one-dimensional model is used in this paper. Whereas, if a three-dimensional regional model was used, then a higher productivity of ozone downstream would be simulated. 相似文献
Meanwhile, high aerosol loading is a serious problem in Taipei. the attenuation of the UV radiation by aerosols cannot be ignored. A numerical simulation shows that the noon ozone level will decrease from 178 to 141ppbv, i. e. about 21% reduction, with deterioration of the visual range from 85 to 5 km.
In the southern Taiwan, industry parks are mixed with the populated Kaohsiung city, hence the large emission of NOx from high chimneys cannot be ignored. in this study, NOx is assumed to be emitted in the layer between 235-460 m high with an emission rate of 0.05 or 0.145 ppbv/sec. the results show that the NOx emitted from the elevated stack lead to a considerable reduction of surface ozone. Such conclusion is obtained due to the fact that a one-dimensional model is used in this paper. Whereas, if a three-dimensional regional model was used, then a higher productivity of ozone downstream would be simulated. 相似文献
250.
Without any incentive to clean up a contaminated site, remediation is often delayed until the site owner is compelled to act by regulatory agencies. In such a context, the selected technology is typically the one that will reach the remediation goals as quickly as possible. Unfortunately, this criterion is often met by overly expensive technologies, resulting in high and sometimes unaffordable total remediation costs, leading to a remediation with a negative net benefit. This study examines the effects of time constraint and benefit value on the optimal remediation strategy for a diesel-contaminated site. This strategy is developed using the technico-economic model METEORS, which takes into account the technology’s effectiveness, the uncertainty of the level of contamination, and the possibility of reducing this uncertainty through either an additional characterization (before selecting and applying a technology) or the monitoring of the remediation technology (during its use). Results of simulations with both economic and temporal constraints support a proactive approach to site remediation. 相似文献