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371.
结合当前我国大气污染控制工作的严峻形势,分析了我国火电行业大气污染控制工作的进展情况、存在问题及控制措施等。 相似文献
372.
pH值是衡量降水酸性的重要指标。本文研究了都匀市降水pH值的变化趋势,并对其酸性降水的特征进行分析,提出了保护大气质量,降低酸雨频率的对策建议。 相似文献
373.
The operation policy for a single reservoir is applied to a rain water cistern system because the functions of a cistern are similar to a simple single reservoir. Since the cistern is a closed system, water loss is negligible. In this study, a dynamic programming analysis has been made to study the effects of the probable weekly rainfall and the water storage in the cistern towards the water consumption policy. The result of this study indicates that the water consumption rate should be adjusted into a lower rate when the water storage in the cistern is low and/or when the expected probable weekly rainfall is low if the owner of the cistern does not want to risk the chance of an empty cistern. The demand for a reliable method for forecasting weekly rainfall is evident in this study. 相似文献
374.
Stanley A. Changnon 《Journal of the American Water Resources Association》1977,13(6):1165-1174
ABSTRACT: Weather modification, both planned by man and that accidentally produced by man, has been under intensive study in Illinois for ten years. Most everyone in Illinois and the Midwest is living in a climate that now is modified inadvertently from its natural state. State atmospheric scientists have tackled weather modification through a series of interrelated studies beginning with climatic studies (to establish the background), experimental design studies, experimental field studies to verify changes and their causes, and finally socio-economic and environmental studies to measure the impacts of weather modification. Studies at St. Louis show that the city acts as a trigger of summer clouds and rainfall leading to 4 to 6 summer days with 3 cm or more rain somewhere just east of the city. Power plants and jet aircraft also accidentally produce climatic changes. A focus on planned weather modification has been on the design of needed midwestern experiments in rainfall enhancement and hail suppression including the societal and environmental impacts. 相似文献
375.
Year-to-year variation in SO4
2-,NO3
-, Ca2+, K+, and Mg2+concentrations in forest floor and mineral soil percolatefrom a forested, podzolic soil at the Turkey Lakes Watershedon the Precambrian Shield was assessed for monotonic trendsbetween 1986 and 1995. Our objective was to examine howrapidly ion concentrations in soil percolate equilibratedafter stabilization of SO4
2- concentrations inprecipitation. Significant negative trends were detected inmonthly Ca2+, and Mg2+ concentrations in forestfloor and SO4
2-, Ca2+, and Mg2+ inmineral soil percolate during the 10-year-period. Thedecline in Ca2+ and Mg2+ was greater than annualdecreases in SO4
2- and NO3
- in forestfloor percolate and proportional to the reduction inSO4
2- in mineral soil percolate. Response ofmineral soil percolate to a 15 molc L-1SO4
2- decrease in wet-only precipitation between1985 and 1986 was a gradual decline in SO4
2-concentration through 1995. The five-year meanSO4
2- concentration in bulk precipitation, forestfloor percolate, and mineral soil percolate decreased 8, 9and 18 molc L-1 from 1986–90 to 1991–95.Microbial (mineralization of organic S) and sorption(release from and/or retention in the pool of insolubleSO4
2-) processes in the soil were logicalexplanations for the observed changes in SO4
2- inmineral soil percolate. 相似文献
376.
Around the city of Izmir, Yamanlar – Manisa (north) Karabelen (south) andKemalpasa mountainous areas exist. The forested area in total covers 122,613.5 ha on these mountainous areas. This forested area has 6,146,387 m3 of wood potential. Industrial complex surroundingthe Aliaga, and thermo-electric power plants working with lignitecoal in the Soma region and some other small industrial establishmentsare located around Izmir and Manisa. These establishements have a vital importance in polluting the air. The forest, which suffers especially from SO2 pollution, consists of Pinus brutia and Pinus nigra. Sulphur contents in 1, 2, 3 yr old needles of the trees were determined to range between 2000–8000 ppm. Microscopic investigation of the tree needles revealed that black blights on the needles indicate destruction of the cells. Annual ring thickness of trees measured showed that there has been a reduction in the forest growth and thisreduction is becoming more serious each year. Reduction in the wood production causes hundreds of billions of Turkish lira of economic loss to the Forestry Administration. It has been concluded at the end of this study that in order to stop theharm that the forests suffer, industrial establishments must pay an `ecological costs' to be added to their product cost items. 相似文献
377.
378.
379.
四川酸雨的综合防治对策研究 总被引:2,自引:0,他引:2
本文在四川酸雨来源、成因、危害的基础上,结合国内外酸雨防治的经验,确定了四川酸雨的主要控制因子、控制目标和致酸污染物的削减率。针对四川的特点,提出了控制四川酸雨的战略和工程措施,为四川的经济发展、城市建设与环境保护等的规划、决策提供了科学依据。 相似文献
380.
Hongjie Xie Xiaobing Zhou Jan M.H. Hendrickx Enrique R. Vivoni Huade Guan Yong Q. Tian Eric E. Small 《Journal of the American Water Resources Association》2006,42(1):237-256
This study examines NEXRAD Stage III product (hourly, cell size 4 km by 4 km) for its ability in estimating precipitation in central New Mexico, a semiarid area. A comparison between Stage III and a network of gauge precipitation estimates during 1995 to 2001 indicates that Stage III (1) overestimates the hourly conditional mean (CM) precipitation by 33 percent in the monsoon season and 55 percent in the nonmonsoon season; (2) overestimates the hourly CM precipitation for concurrent radar‐gauge pairs (nonzero value) by 13 percent in the monsoon season and 6 percent in the nonmonsoon season; (3) overestimates the seasonal precipitation accumulation by 11 to 88 percent in monsoon season and underestimates by 18 to 89 percent in the nonmonsoon season; and (4) either overestimates annual precipitation accumulation up to 28.2 percent or underestimates it up to 11.9 percent. A truncation of 57 to 72 percent of the total rainfall hours is observed in the Stage III data in the nonmonsoon season, which may be the main cause for both the underestimation of the radar rainfall accumulation and the lower conditional probability of radar rainfall detection in the nonmonsoon season. The study results indicate that the truncation caused loss of small rainfall amounts (events) is not effectively corrected by the real‐time rain gauge calibration that can adjust the rainfall rates but cannot recover the truncated small rainfall events. However, the truncation error in the monsoon season may be suppressed due to the larger rainfall rate and/or combined effect of overestimates by bright band and hail contaminations, virga, advection, etc. In general, improvement in NEXRAD performance since the monsoon season in 1998 is observed, which is consistent with the systematic improvement in the NEXRAD network. 相似文献