着重介绍模拟河川、湖泊与水库水质状况的各种模型 ,论述了其数学模型的分类、模拟及用途 ,并对有关通用软件如QUAL2E ,QUAL2E UNCAS ,WASP ,CE QUAL RIV1,WQRRS ,HEC 5Q ,SE LECT ,CE QUAL W 2和CE QUAL R1等作了说明 ,最后对其中 7个...着重介绍模拟河川、湖泊与水库水质状况的各种模型 ,论述了其数学模型的分类、模拟及用途 ,并对有关通用软件如QUAL2E ,QUAL2E UNCAS ,WASP ,CE QUAL RIV1,WQRRS ,HEC 5Q ,SE LECT ,CE QUAL W 2和CE QUAL R1等作了说明 ,最后对其中 7个代表性模型QUAL2E ,WASP ,CE QUAL RIV1,CE QUAL R1,CE QUAL W 2 ,WQRRS和HEC 5Q进行了简要的比较。展开更多
Effects of elevated O_3 on the yields of rice and winter wheat were studied by using open-top chambers(OTCs). Results showed that compared to the control treatment, 200 ppb, 100 ppb, 50 ppb treatments caused a 80.4%, ...Effects of elevated O_3 on the yields of rice and winter wheat were studied by using open-top chambers(OTCs). Results showed that compared to the control treatment, 200 ppb, 100 ppb, 50 ppb treatments caused a 80.4%, 58.6% and 10.5% decrease in grain yields per winter wheat plant and a 49.1%, 26.1% and 8.2% decrease in grain yield per rice plant, respectively. According to the dose-response relation educed from OTCs experiment and the monitor data of O_3 concentrations in spots, it was estimated that the yield losses of rice and winter wheat resulted by O_3 pollution in the Yangtze River Delta region in 1999 were 0.599 million ton and 0.669 million ton, economic losses were 0.539 billion RMB Yuan and 0.936 billion RMB Yuan, respectively.展开更多
PM2.5 and PM10 samples were collected at four major cities in the Pearl River Delta （PRD）, South China, during winter and summer in 2002. Six water-soluble ions, Na^＋, NH4＋, K^＋, Cl^-, NO3^- and SO4^2- were measu...PM2.5 and PM10 samples were collected at four major cities in the Pearl River Delta （PRD）, South China, during winter and summer in 2002. Six water-soluble ions, Na^＋, NH4＋, K^＋, Cl^-, NO3^- and SO4^2- were measured using ion chromatography. On average, ionic species accounted for 53.3% and 40.5% for PM2.5 and PM10, respectively in winter and 39.4% and 35.2%, respectively in summer. Secondary ions such as sulfate, nitrate and ammonium accounted for the major part of the total ionic species. Sulfate was the most abundant species followed by nitrate. Overall, a regional pollution tendency was shown that there were higher concentrations of sulfate, nitrate and ammonium in Guangzhou City than those in the other PRD cities. Significant seasonal variations were also observed with higher levels of species in winter but lower in summer. The Asian monsoon system was favorable for removal and diffusion of air pollutants in PRD in summer while highly loading of local industrial emissions tended to deteriorate the air quality as well. NO3^-/SO4^2- ratio indicated that mobile sources have considerably contribution to the urban aerosol, and stationary sources should not be neglected. Besides the primary emissions, complex atmospheric reactions under favorable weather conditions should be paid more attention for the control of primary emission in the PRD region.展开更多
文摘着重介绍模拟河川、湖泊与水库水质状况的各种模型 ,论述了其数学模型的分类、模拟及用途 ,并对有关通用软件如QUAL2E ,QUAL2E UNCAS ,WASP ,CE QUAL RIV1,WQRRS ,HEC 5Q ,SE LECT ,CE QUAL W 2和CE QUAL R1等作了说明 ,最后对其中 7个代表性模型QUAL2E ,WASP ,CE QUAL RIV1,CE QUAL R1,CE QUAL W 2 ,WQRRS和HEC 5Q进行了简要的比较。
文摘Effects of elevated O_3 on the yields of rice and winter wheat were studied by using open-top chambers(OTCs). Results showed that compared to the control treatment, 200 ppb, 100 ppb, 50 ppb treatments caused a 80.4%, 58.6% and 10.5% decrease in grain yields per winter wheat plant and a 49.1%, 26.1% and 8.2% decrease in grain yield per rice plant, respectively. According to the dose-response relation educed from OTCs experiment and the monitor data of O_3 concentrations in spots, it was estimated that the yield losses of rice and winter wheat resulted by O_3 pollution in the Yangtze River Delta region in 1999 were 0.599 million ton and 0.669 million ton, economic losses were 0.539 billion RMB Yuan and 0.936 billion RMB Yuan, respectively.
基金Project supported by the National Natural Science Founding of China(No.20347003,40121303)the Research Grants Council of Hong Kong(No.PolyU5038/01E,PolyU5145/03E)the Area of Strategic Development on Atmospheric and Urban Air Pollution of The Hong Kong Polytechnic University(No.A516,A510).
文摘PM2.5 and PM10 samples were collected at four major cities in the Pearl River Delta （PRD）, South China, during winter and summer in 2002. Six water-soluble ions, Na^＋, NH4＋, K^＋, Cl^-, NO3^- and SO4^2- were measured using ion chromatography. On average, ionic species accounted for 53.3% and 40.5% for PM2.5 and PM10, respectively in winter and 39.4% and 35.2%, respectively in summer. Secondary ions such as sulfate, nitrate and ammonium accounted for the major part of the total ionic species. Sulfate was the most abundant species followed by nitrate. Overall, a regional pollution tendency was shown that there were higher concentrations of sulfate, nitrate and ammonium in Guangzhou City than those in the other PRD cities. Significant seasonal variations were also observed with higher levels of species in winter but lower in summer. The Asian monsoon system was favorable for removal and diffusion of air pollutants in PRD in summer while highly loading of local industrial emissions tended to deteriorate the air quality as well. NO3^-/SO4^2- ratio indicated that mobile sources have considerably contribution to the urban aerosol, and stationary sources should not be neglected. Besides the primary emissions, complex atmospheric reactions under favorable weather conditions should be paid more attention for the control of primary emission in the PRD region.
