阿勒泰地区雾的气候特征与变化趋势及其对人体的影响研究

利用1961年-2012年阿勒泰地区气象观测资料,对雾的时空分布特征和变化趋势进行分析。结果表明:阿勒泰地区雾日数在时间分布上,初春的3月出现最多;冬季(12月-翌年2月)雾出现的比例最高,占37.6%。20世纪80年代年雾出现日数最多,2000年至今最少。阿勒泰地区雾日数在空间分布上也不是很均匀,区域性为西部的吉木乃、哈巴河县最多,东部的富蕴、青河县最少。阿勒泰地区雾出现日数年变化率与各县站的变化趋势一致,均呈明显的下降趋势,在1966年出现了减少的突变现象。R/S方法分析表明,各县站未来的年雾出现日数仍会呈减少趋势,雾天对人体有一定的影响。     

Emissions associated with meeting the future global wheat demand: A case study of UK production under climate change constraints

Climate change, population growth and socio-structural changes will make meeting future food demands extremely challenging. As wheat is a globally traded food commodity central to the food security of many nations, this paper uses it as an example to explore the impact of climate change on global food supply and quantify the resulting greenhouse gas emissions. Published data on projected wheat production is used to analyse how global production can be increased to match projected demand. The results show that the largest projected wheat demand increases are in areas most likely to suffer severe climate change impacts, but that global demand could be met if northern hemisphere producers exploit climate change benefits to increase production and narrow their yield gaps. Life cycle assessment of different climate change scenarios shows that in the case of one of the most important wheat producers (the UK) it may be possible to improve yields with an increase of only 0.6% in the emission intensity per unit of wheat produced in a 2 °C scenario. However, UK production would need to rise substantially, increasing total UK wheat production emissions by 26%. This demonstrates how national emission inventories and associated targets do not incentivise minimisation of global greenhouse gas emissions while meeting increased food demands, highlighting a triad of challenges: meeting the rising demand for food, adapting to climate change and reducing emissions.     

Annual nonmethane hydrocarbon trends in Beijing from 2000 to 2019

High loads of ground-level ozone have occurred with the implementation of the Air Pollution Prevention and Control Action Plan. However, the long temporal variation in precursor nonmethane hydrocarbons(NMHCs) has rarely been studied. In this study, we examined the evolution of NMHCs in Beijing based on ambient measurements from 2000 to 2019. The results indicated that the annual variation of ambient NMHCs during 2000 and 2019 could be divided into two stages. The mixing ratios of NMHCs rapidly r...     

污水生物脱氮除磷工艺的现状与发展

阐述了污水生物脱氮除磷的机理,并按空间和时间顺序介绍了一些经典的脱氮除磷工艺,对其发展趋势作了展望。通过对除磷机理及工艺的介绍和分析,提出应加深对生物除磷机理的研究,从微生物的角度进行工艺调控。     

广州主要工业源排放的气态污染物扩散模拟研究

以广州省控工业污染源排放的气态污染物(SO₂、NO_x为主要研究对象,通过中尺度气象模式MM5与空气质量模式CALPUFF耦合,模拟11月典型气象条件下, SO₂和NO_x的扩散传输过程,研究其时空分布特征,并分析省控工业污染源排放对特定区域(主要针对2010年亚运场馆)空气质量的影响。结果表明,主要受典型风速的影响,SO₂和NO_x浓度具有明显的时空分布不均匀性。浓度高峰值主要出现在晚间至凌晨时段,而浓度低峰值主要出现在白天至中午时段。受污染源分布、排放高度和风向的影响,荔湾区和越秀区污染物浓度较高,且在广州西南部形成较明显的污染带;且这些省控污染源对南沙体育馆空气质量有较大影响。 研究结果对广州空气污染来源分析具有一定参考意义。     

循环经济的国际发展趋势

从几个方面重点介绍了循环经济的国际发展趋势;把发展循环经济纳入法制化轨道;形成政府倡导、全民参与的意识和环境;大力促进循环经济产业化;鼓励技术创新,促进循环经济的发展。为我国发展循环经济,实现全面建设小康社会目标提供借鉴经验。     

从第31届国际地质大会命题看：地球科学研究的热点和趋势

本文论述了第 31届国际地质大会学科和专题命题情况 ,统计了大会收到的论文和摘要数并将各命题重新排序。将位于前 12位的学科和前 5位的专题命题进一步列出重点讨论题目和摘要数。通过与第 30届国际地质大会命题的比较 ,试图大致了解国际地球科学研究的热点和趋势 ;通过上述分析和了解 ,就地球科学与可持续发展阐述了笔者的认识 ,提出了地球科学基础性研究和应用基础研究的重点领域     

Trends in management plans and guides: 25 years of experience from Southern France

This study analysed 14 management plans and guidelines from a 25-year period to understand trends in conservation planning. A Rosetta Stone Analysis was used for the systematic comparison of plans and guidelines. Management plans incorporated management philosophies, management scenarios, opportunities for infrastructure, and plans for data collection by 2000. As of 2010, they incorporated ecosystem services, stakeholders’ objectives and methods for storing and analysing data. The results demonstrate the complex nature of management plans, with an important workload for site managers. Recommendations for future planning include adjustments in planning timeframes and a better identification of conservation targets from initial stages.     

Long‐Term Trends of Nutrients and Sediment from the Nontidal Chesapeake Watershed: An Assessment of Progress by River and Season

To assess historical loads of nitrogen (N), phosphorus (P), and suspended sediment (SS) from the nontidal Chesapeake Bay watershed (NTCBW), we analyzed decadal seasonal trends of flow‐normalized loads at the fall‐line of nine major rivers that account for >90% of NTCBW flow. Evaluations of loads by season revealed N, P, and SS load magnitudes have been highest in January‐March and lowest in July‐September, but the temporal trends have followed similar decadal‐scale patterns in all seasons, with notable exceptions. Generally, total N (TN) load has dropped since the late 1980s, but particulate nutrients and SS have risen since the mid‐1990s. The majority of these rises were from Susquehanna River and relate to diminished net trapping at the Conowingo Reservoir. Substantial rises in SS were also observed, however, in other rivers. Moreover, the summed rise in particulate P load from other rivers is of similar magnitude as from Susquehanna. Dissolved nutrient loads have dropped in the upland (Piedmont and above) rivers, but risen in two small rivers in the Coastal Plain affected by lagged groundwater input. In addition, analysis of fractional contributions revealed consistent N trends across the upland watersheds. Finally, total N:total P ratios have declined in most rivers, suggesting the potential for changes in nutrient limitation. Overall, this integrated study of historical data highlights the value of maintaining long‐term monitoring at multiple watershed locations.     

Evaluating Alternative Temporal Survey Designs for Monitoring Wetland Area and Detecting Changes Over Time in California

Evaluation of wetland extent and changes in extent is a foundation of many wetland monitoring and assessment programs. Probabilistic sampling and mapping provides a cost‐effective alternative to comprehensive mapping for large geographic areas. One unresolved challenge for probabilistic or design‐based approaches is how best to monitor both status (e.g., extent at a single point in time) and trends (e.g., changes in extent over time) within a single monitoring program. Existing wetland status and trends (S&T) monitoring programs employ fixed sampling locations; however, theoretical evaluation and limited implementation in other landscape monitoring areas suggest that alternative designs could increase statistical efficiency and overall accuracy. In particular, designs that employ both fixed and nonfixed sampling locations (alternately termed permanent and temporary samples), termed sampling with partial replacement (SPR), are considered to efficiently and effectively balance monitoring current status with detection of trends. This study utilized simulated sampling to assess the performance of fixed sampling locations, SPR, and strictly nonfixed designs for monitoring wetland S&T over time. Modeled changes in wetland density over time were used as inputs for sampling simulations. In contrast to previous evaluations of SPR, the results of this study support the use of a fixed sampling design and show that SPR may underestimate both S&T.