Background monitoring and long-range transport of atmospheric CFC-11 and CFC-12 at Kosan, Korea

The background concentrations of atmospheric CFC-11 and CFC-12were monitored to assess their impact on stratospheric ozone depletion and global warming from September 1995 to March 1999 at Kosan, Korea, located at eastern margin of the Asian Continent. The concentrations of atmospheric CFC-11 at Kosan have decreased slightly, at a rate of –2.5 pptv yr^-1, over the period in response to the Montreal Protocol. The CFC-12 mixing ratio at Kosan continues to increase in the atmosphere at a rate of 5.7 pptv yr^-1 despite international regulations, because of its extreme atmosphere persistence. Recent trends ofthese two chlorofluorocarbons at Kosan, Korea were concordant with those of the northern hemispheric background monitored unitat Mauna Loa, Hawaii. The maximum seasonal mean mixing ratios of CFC-11 and CFC-12 at Kosan, Korea, were 270±4 pptv inthe spring and 538±9 pptv in the winter, and the corresponding seasonal minima were 267±7 and 529±12 pptv. This occurred in the summer and was due to southeasterlywinds from the northwestern Pacific Ocean. By performing a three-day isentropic backward trajectory analysis, it was shownthat air masses at Kosan, and with the exception of summer, mainly originated from central and northern China. In particular, the mixing ratios of these two contaminant speciesare closely related with their air mass trajectories.     

全球及区域尺度土地覆盖土地利用遥感研究的现状和展望

９０年代以来,利用遥感进行大面积土地覆盖土地利用的研究取得了一系列重要进展。已建立的全球及区域土地覆盖土地利用数据库正在得到广泛的应用,取得明显的社会效益和经济效益。土地覆盖土地利用及其变化的研究成果也被应用于有关全球环境变化国际公约的执行监督。利用遥感进行大面积土地详查已经逐步摆脱单一制图的传统概念,正在向建立以应用为目的且便于用户使用的综合信息数据库的方向迈进。此外,如何对大面积土地覆盖数据库进行精度评价已引起广泛重视,出现了一些新的理论和研究方法。进入２１世纪,全球和区域土地覆盖土地利用的遥感研究将进一步深化     

Microenvironmental time-activity patterns in Chongqing, China

An investigation using recall questionnaires was conducted in winter and autumn 2006 to evaluate the time-activity patterns in Chongqing, China. The average time spent in seven microenvironments (MEs) including outdoors, transit, living room, bedroom, kitchen, classroom/office, and other indoors were found to be about 3.5, 1.1, 2.5, 9.7, 1.4, 4.2, and 1.7 h per day, respectively. According to the results of a nonparametric test, the sampling period and day of week were significant for the variation of the time spent in all MEs except for transit and outdoors. The time budget was analyzed using a general linear model (GLM), which exhibited significant variability by demographic factors such as gender, age, residence, education, and household income.     

稻油不同轮作模式对农田甲烷和氧化亚氮排放的影响

以南方稻区不同轮作模式为研究对象,采用静态箱-气相色谱法研究水稻-油菜轮作处理的甲烷(CH₄)和氧化亚氮(N₂O)排放特征,并估算稻田增温潜势(GWP)和温室气体排放强度(GHGI).结果表明,双季稻田、一季中(晚)稻田、油菜地和休闲地CH₄平均排放量分别为135.25, 55.64、 5.05和1.89 kg·hm^-2,稻季CH₄排放占不同轮作周年CH₄排放的91.8%～98.5%,稻田土壤水溶性有机碳与CH₄排放呈显著正相关,常规晚稻稻田CH₄排放比杂交晚稻高18.7%(P<0.05);双季稻田、一季中(晚)稻田、油菜地和休闲地N₂O平均排放量分别为0.94、 0.64、 1.38和0.24 kg·hm^-2,油菜地的N₂O排放占周年排放的57.2%～70.2%,双季稻和一季稻处理的冬闲农田N₂O排放占周年排放的17....     

环流型对武汉市臭氧污染浓度的影响分析

本文统计了武汉市臭氧污染超标日和清除日的环流类型,并对超标日环流型对应的气象要素进行了对比分析,揭示了环流型对臭氧浓度的影响.结果表明:①按照高空环流分类,武汉市臭氧超标环流型主要有:槽后西北气流型(占比最高,29％)、西太平洋副热带高压型、脊型、平直西风气流型、大陆高压型;臭氧清除环流型主要有:槽前西南气流型(占比最...     

富营养化与温度因素对太湖藻类生长的影响研究

为了研究气候变暖和富营养化对湖泊水生态系统的影响,应用阿列纽斯方程修正的Monod生长模型定量研究长期以来太湖藻类生物量与营养元素和温度的关系.研究表明,在近年来的富营养化状况下,年均气温每增加1.0℃,年均藻类生物量增加0.145倍.湖泊富营养化越严重.年平均气温对藻类生长的影响就越大,由此可以定量评估和预测年均气温...     

Selection of both habitat and genes in specialized and endangered caribou

Genetic mechanisms determining habitat selection and specialization of individuals within species have been hypothesized, but not tested at the appropriate individual level in nature. In this work, we analyzed habitat selection for 139 GPS-collared caribou belonging to 3 declining ecotypes sampled throughout Northwestern Canada. We used Resource Selection Functions comparing resources at used and available locations. We found that the 3 caribou ecotypes differed in their use of habitat suggesting specialization. On expected grounds, we also found differences in habitat selection between summer and winter, but also, originally, among the individuals within an ecotype. We next obtained Single Nucleotide Polymorphisms (SNPs) for the same caribou individuals, we detected those associated to habitat selection, and then identified genes linked to these SNPs. These genes had functions related in other organisms to habitat and dietary specializations, and climatic adaptations. We therefore suggest that individual variation in habitat selection was based on genotypic variation in the SNPs of individual caribou, indicating that genetic forces underlie habitat and diet selection in the species. We also suggest that the associations between habitat and genes that we detected may lead to lack of resilience in the species, thus contributing to caribou endangerment. Our work emphasizes that similar mechanisms may exist for other specialized, endangered species.     

人类活动对轨道尺度全球季风区降水影响的模拟研究【封面文章】

目前，人类活动导致的温室气体增加是全球气候变化的主要驱动因素之一，但其在轨道尺度上对未来气候影响的研究却很少。利用海-陆-气耦合模式，对早全新世（距今10 ka前）、现代和未来10 ka后的气候进行了一系列敏感性数值试验，主要探讨了在轨道尺度上自然强迫和人为温室气体对全球季风区气候变化的可能影响。模拟结果表明：在自然强迫驱动下，未来10 ka后的地球气候与早全新世类似，北半球的地表温度和降水将高于工业革命前的水平，而南半球则相反。在人类活动驱动下，未来10 ka后全球地表温度将显著增加，除北美季风区外，所有季风区雨季的降水都将增加。受人类活动的影响，与工业革命前相比，极端降水和大气有效降水也将增加。在自然强迫下，雨季大气有效降水的增加主要是由于动力作用引起的大气环流增强，而人类活动引起的现代和未来10 ka后大气有效降水的增加主要是由于热力作用引起的大气水汽增加所致。     

Smart meters for enhanced water supply network modelling and infrastructure planning

To design water distribution network infrastructure, water utilities formulate daily demand profiles and peaking factors. However, traditional methods of developing such profiles and peaking factors, necessary to carry out water distribution network modelling, are often founded on a number of assumptions on how top-down bulk water consumption is attributed to customer connections and outdated demand information that does not reflect present consumption trends; meaning infrastructure is often unnecessarily overdesigned. The recent advent of high resolution smart water meters allows for a new novel methodology for using the continuous ‘big data’ generated by these meter fleets to create evidence-based water demand curves suitable for use in network models. To demonstrate the application of the developed method, high resolution water consumption data from households fitted with smart water meters were collected from the South East Queensland and Hervey Bay regions in Australia. Average day (AD), peak day (PD) and mean day maximum month (MDMM) demand curves, often used in water supply network modelling, were developed from the herein created methodology using both individual end-use level and hourly demand patterns from the smart meters. The resulting modelled water demand patterns for AD, PD and MDMM had morning and evening peaks occurring earlier and lower main peaks (AD: 12%; PD: 20%; MDMM: 33%) than the currently used demand profiles of the regions’ water utility. The paper concludes with a discussion on the implications of widespread smart water metering systems for enhanced water distribution infrastructure planning and management as well as the benefits to customers.     

Redefining and mapping global irreplaceability

Irreplaceability is a concept used to describe how close a site is to being essential for achieving conservation targets. Current methods for measuring irreplaceability are based on representative combinations of sites, giving them an extrinsic nature and exponential computational requirements. Surrogate measures based on efficiency (complementarity) are often used as alternatives, but they were never intended for this purpose and do not measure irreplaceability. Current approaches used to estimate irreplaceability have key limitations. Some of these are a result of the tools used, but some are due to the nature of the current definition of irreplaceability. For irreplaceability to be stable and useful for conservation purposes and to resolve limitations, irreplaceability measures should adhere to five axioms; baseline coherence, monotonic responsiveness, proportional responsiveness, intrinsic stability, and bounded outputs. We designed a robust method for measuring a site's proximity to irreplaceability that adheres to these requirements and used it to develop the first systematic global map of irreplaceability based on data for terrestrial vertebrates (n = 29,837 species, >1 million grid cells). At least 3.5% of land surface was highly irreplaceable, and 47.6% of highly irreplaceable cells were contained in 12 countries. More generous thresholds of irreplaceability flag greater portions of land surface that would still be realistic to protect under current global objectives. Irreplaceable sites should form a critical component of any global conservation plan and should be part of the UN Convention on Biological Diversity's post2020 Global Biodiversity Framework strategy, forming part of the 30% protection by 2030 target that is gaining support. The reliable identification of irreplaceable sites will be crucial to halting extinctions.