广西喀斯特干旱农业区干旱遥感监测模型研究

广西中部喀斯特平原区是广西重要的粮食生产基地,但旱灾已成为该地区经济发展的障碍.利用EOS/MODIS数据,采用植被状态指数(IVC)和温度条件指数(ITC),构建了干旱指数ID的遥感监测模型, 统计分析了ID与农业受旱率的相关系数,从而确定了模型中各参数的权重系数.将该模型应用于2005年秋旱监测,经与旱情实况及前人研究成果进行对比分析,验证了干旱指数ID的有效性.通过对ID随ITC和IVC变化的敏感性评价,结果表明,ITC和IVC都能反映旱情变化,但ITC反映旱情的敏感性高于IVC,以ITC和IVC为因子构建的干旱遥感监测模型适用于广西中部喀斯特干旱农业区的旱情遥感监测.     

大连市中心区O3污染特征分析

本文采用2007年大连市环境自动监测数据,分析了城市中心区O3的污染特征。结果表明：O3质量浓度的最大值出现在午后15：00—17：00,比太阳辐射强度最大值的出现时间滞后2h左右;O3质量浓度的季节性变化十分显著,春夏季较高,秋季次之,冬季最低;汽车尾气是近地面O3污染的主要原因。     

Performance of IUCN proxies for generation length

One of the criteria used by the International Union for Conservation of Nature (IUCN) to assess threat status is the rate of decline in abundance over 3 generations or 10 years, whichever is longer. The traditional method for calculating generation length (T) uses age‐specific survival and fecundity, but these data are rarely available. Consequently, proxies that require less information are often used, which introduces potential biases. The IUCN recommends 2 proxies based on adult mortality rate, = α + 1/d, and reproductive life span, = α + z^*RL, where α is age at first reproduction, d is adult mortality rate, RL is reproductive life span, and z is a coefficient derived from data for comparable species. We used published life tables for 78 animal and plant populations to evaluate precision and bias of these proxies by comparing and with true generation length. Mean error rates in estimating T were 31% for and 20% for , but error rates for were 16% when we subtracted 1 year ( ), as suggested by theory; also provided largely unbiased estimates regardless of the true generation length. Performance of depends on compilation of detailed data for comparable species, but our results suggest taxonomy is not a reliable indicator of comparability. All 3 proxies depend heavily on a reliable estimate of age at first reproduction, as we illustrated with 2 test species. The relatively large mean errors for all proxies emphasized the importance of collecting the detailed life‐history information necessary to calculate true generation length. Unfortunately, publication of such data is less common than it was decades ago. We identified generic patterns of age‐specific change in vital rates that can be used to predict expected patterns of bias from applying .     

Optimum ridge-to-furrow ratio in ridge-furrow mulching systems for improving water conservation in maize (Zea may L.) production

Environmental Science and Pollution Research - Water-saving cultivation techniques have been attracting increased attention worldwide. Ridge-furrow mulching system (RFMS), as a prospective...     

Overview of surface measurements and spatial characterization of submicrometer particulate matter during the DISCOVER-AQ 2013 campaign in Houston,TX

The sources of submicrometer particulate matter (PM₁) remain poorly characterized in the industrialized city of Houston, TX. A mobile sampling approach was used to characterize PM₁ composition and concentration across Houston based on high-time-resolution measurements of nonrefractory PM₁ and trace gases during the DISCOVER-AQ Texas 2013 campaign. Two pollution zones with marked differences in PM₁ levels, character, and dynamics were established based on cluster analysis of organic aerosol mass loadings sampled at 16 sites. The highest PM₁ mass concentrations (average 11.6 ± 5.7 µg/m³) were observed to the northwest of Houston (zone 1), dominated by secondary organic aerosol (SOA) mass likely driven by nighttime biogenic organonitrate formation. Zone 2, an industrial/urban area south/east of Houston, exhibited lower concentrations of PM₁ (average 4.4 ± 3.3 µg/m³), significant organic aerosol (OA) aging, and evidence of primary sulfate emissions. Diurnal patterns and backward-trajectory analyses enable the classification of airmass clusters characterized by distinct PM sources: biogenic SOA, photochemical aged SOA, and primary sulfate emissions from the Houston Ship Channel. Principal component analysis (PCA) indicates that secondary biogenic organonitrates primarily related with monoterpenes are predominant in zone 1 (accounting for 34% of the variability in the data set). The relevance of photochemical processes and industrial and traffic emission sources in zone 2 also is highlighted by PCA, which identifies three factors related with these processes/sources (~50% of the aerosol/trace gas concentration variability). PCA reveals a relatively minor contribution of isoprene to SOA formation in zone 1 and the absence of isoprene-derived aerosol in zone 2. The relevance of industrial amine emissions and the likely contribution of chloride-displaced sea salt aerosol to the observed variability in pollution levels in zone 2 also are captured by PCA.

Implications: This article describes an urban-scale mobile study to characterize spatial variations in submicrometer particulate matter (PM₁) in greater Houston. The data set indicates substantial spatial variations in PM₁ sources/chemistry and elucidates the importance of photochemistry and nighttime oxidant chemistry in producing secondary PM₁. These results emphasize the potential benefits of effective control strategies throughout the region, not only to reduce primary emissions of PM₁ from automobiles and industry but also to reduce the emissions of important secondary PM₁ precursors, including sulfur oxides, nitrogen oxides, ammonia, and volatile organic compounds. Such efforts also could aid in efforts to reduce mixing ratios of ozone.     

Characteristics and management of domestic waste in a rural area of the Tibetan Plateau

In the rural area of the Tibetan Plateau (RATP), the characteristics of domestic waste, people’s environmental awareness, people’s willingness to pay and their influence factors were firstly studied by questionnaires, field samplings and laboratory tests. The results showed that, in the RATP, the generation of domestic waste was 85 g?d-1 per capita and it was mainly composed of plastics, inert waste, kitchen waste, glass and paper. The waste bulk density, moisture content, ash, combustible and low calorific value were 65 kg?m-3, 19.25%, 44.90%, 35.85% and 10,520 kJ?kg-1 respectively. These characteristics are influenced by income sources and geographical position to some extent. Classified collection should be promoted widely on the household and the village basis. Compost, fermentation, landfill, bioreactor landfill and semi-aerobic landfill have been approved as effective techniques to treat domestic waste, except incineration. The distance of 50–800 m between each collection facility and the disposal fee of around $0.8 per month per household are suggested. For suburbs or large population villages, it’s better to treat domestic waste by the centralized way. But for the remote rural areas, a decentralized way is proposed. Significantly, the educational and economic influence should be considered into an effective domestic waste management program.

Implications:?The current situatio n of the environment in the rural areas of the Tibetan Plateau (RATP) was surveyed. There, the generation of organics and moisture of domestic waste were low but ash, recyclables, and combustibles were high. People’s knowledge of domestic waste was absent but their participation in management was strong. Based on the current situation, compost, fermentation, and landfill were effective but incineration was inappropriate. Also, a localized mini landfill for a cluster of villages and or settlements was the best method there.     

化学沉淀法强化常规工艺应急去除水中的镉

在常规工艺基础上,通过投加氢氧化钠,实验进行了应急去除重金属镉的研究。实验结果表明,该方法能有效去除饮用水水源的镉,效果稳定,可进行应急处理。对pH、镉初始浓度和混凝剂投加量3个影响因素的灰色关联分析表明,3个因素对镉去除效果影响的大小排序为:滤后水pH>混凝剂投加量>镉初始浓度。在水源镉突发污染时,在原有常规水处理工艺基础上,通过控制滤后水pH可实现对重金属镉的去除,pH的控制值与水源水质有关。     

节能环保型燃烧器技术特点分析及应用

由于原广泛使用的北美燃烧器存在技术落后、安全保护措施欠缺、操作复杂、安全隐患多、节能和环保不达标等问题,为适应当前注汽锅炉安全可靠、高效经济和低污染排放的运行要求,国内稠油热采注汽锅炉逐步应用新型节能燃烧器。通过总结各类新型节能燃烧器在燃烧效率、控制理念、动态监测、节能环保、燃料保护等方面的技术性能,分析其具有燃烧效率高、节能环保、安全可靠、自动控制水平高等特点,并验证实际运行效果,展望工业燃烧器技术发展趋势,为指导燃烧器选型和技术管理提供依据和参考。     

遗传投影寻踪回归在城市环境质量评价中的应用

引入投影降维的思想,将遗传投影寻踪与回归分析技术运用到城市环境质量评价中。将此技术与神经网络方法进行实例比较,投影寻踪回归方法不但可以合理地作出环境质量的综合评价,而且消除了神经网络方法中类别判断不够精确的影响。     

辉县市城区环境空气质量现状及污染防治对策

对辉县市城区2006—2011年间环境空气质量监测数据进行了评价,并对城区污染物浓度时空变化进行了分析。结果表明,辉县市城区大气污染主要表现为可吸入颗粒物污染严重,主要是能源结构不合理、锅炉废气污染严重、城区道路保洁方式落后等原因造成的,由此提出了合理规划城市布局、减少结构性污染等对策。