经验正交函数方法和TRMM数据对长江流域降水模式与极端水文过程的研究

气候变化加剧了极端天气和水文事件的发生,降水是区域干旱与洪水事件最直接驱动因素。以TRMM/PR月累积降水反演遥感数据为基础,利用经验正交函数EOF（Empirical Orthogonal Function）方法对长江流域降水时空变化模式进行提取,并对比分析了主要模式振幅强弱与极端水文事件的对应关系。结果表明在流域尺度上EOF方法及TRMM/PR数据可以较好地识别降水主要模式,通过时空尺度变换成功揭示主要降水模式强弱与流域极端水文事件的对应关系。鉴于日益丰富的巨量水文气象时空数据,EOF方法在模式提取、水文模拟、极端事件预估及灾害适应性研究等方面具有应用潜力     

基于Alos的遥感技术在江苏省太湖流域一级保护区水环境综合整治中的应用

江苏省太湖流域一级保护区综合整治是治理太湖的重点工作,直接关系太湖湖体水环境质量。本文通过遥感技术对江苏省太湖流域一级保护区土地利用类型进行了解析,将一级保护区土地分解为15种利用类型,结果表明:一级保护区建设用地总面积为235.1km2,土地开发强度为17.2%。高强度的土地开发是造成太湖及主要入湖河流污染的首要原因,故整治太湖流域一级保护区首要任务是严格控制建设用地规模,降低污染物排放负荷。     

非均质多孔介质对水平潜流人工湿地水力效率的影响

对比以不同粒径(4～9、8～12、11～17mm)非均质多孔介质(玻璃珠)作为基质的水平潜流人工湿地(以有机玻璃板材模拟)的水力效率、水力停留时间等参数,并参照其流态变化进行分析。结果表明:(1)均以上端为进水口、下端为出水口,水流流经不同粒径玻璃珠的水平潜流人工湿地会产生不同的流态。(2)玻璃珠粒径小(4～9mm)的水平潜流人工湿地中,染料在其中运动并最终能够迁移到出水口的有效空间最大,空间利用率最大,则有效体积比最大,染料流经区域面积最大;转角处染料呈圆角流过,死区范围小。(3)当玻璃珠粒径为4～9mm时,水平潜流人工湿地具有最长的平均水力停留时间(0.437 8h)和最小的水流散度(标准方差为0.052 5),使得水平潜流人工湿地的有效体积比最高(0.495 7),水力效率也最高(0.469 6)。随着粒径的增大,平均水力停留时间缩短,水流散度增大,而有效体积比和水力效率均呈减小趋势。(4)合理的水力停留时间分布能够提高有效体积比,而有效体积比越高,即污水在水平潜流人工湿地中运动并最终能够迁移到出水口的有效空间越大,污染物与基质以及附着在基质上的微生物的接触越充分,从而提高污染物的去除率。     

秭归县植被结构演变及土壤侵蚀评价

为详细了解水库建设期秭归县植被结构演变及土壤侵蚀风险情况,使用TM和SPOT等中高分辨率遥感数据获取的秭归县1992、2007年1〖DK〗∶50 000土地利用分类、植被覆盖度、土壤侵蚀风险及1999～2007年SPOT VEGETATION NDVI等。利用景观格局方法研究植被景观格局演变,分析植被结构与土壤侵蚀风险变化特点。结果表明：1992～2007年,植被景观格局更加破碎,斑块离散程度变大,多样性提高,乔、灌等仍是优势类型,受不同人类政策的影响,不同类型植被类型景观特征响应表现出差异性。植被覆盖度得到改善,其中秭归中南部植被水平密度结构得到明显改善,对降低土壤侵蚀风险起到了积极作用。水库周边地区作为人类活动扰动的集中区,水土保持任务依然艰巨。通过遥感和GIS手段分析区域土地景观格局演变及其生态环境效应,分析变化背后的驱动机制和限制因素,甄别人类活动影响力,为研究三峡人地关系和谐发展提供借鉴和参考     

梁子湖水体和底泥中微量元素及重金属的空间分布格局及污染评价

利用多元统计方法研究了湖北梁子湖水体及底泥中12种微量元素和重金属(As,Ba,Co,Cr,Cu,Hg,Mn,Ni,Pb,Sb,Sr和Zn)的含量及空间格局,并通过饮用水及地表水质量标准及地质累积指数评价梁子湖水质及底泥状况。结果表明:梁子湖的水体质量较好,仅Cu是潜在污染物质;对湖泊底质而言,As是主要污染物质,Cu、Pb和Zn处在轻微的污染状态。空间格局显示:受人类活动的影响,湖泊水体中的重金属分布有较强的区域性,最大值出现在人类活动相对集中的梁子岛附近;在湖泊底泥中由于地质背景一致性而差别不大。相关分析表明,较之湖泊水体,湖泊底泥中的重金属元素的关系更密切,强相关性说明它们可能有共同的来源。未来研究应结合湖泊中大型水生植物及鱼类的重金属含量更全面考虑生态学效应,为恢复湖泊生态环境的管理提供重要参考。     

道路绿化种植抗污染植物模式研究

在广州市广花公路黄石路段建立了 3个道路绿化抗污染模式进行研究 ,生长 2年后测定各模式对NOx、CO和TSP等大气污染物质的净化效果。结果表明 ,若植物种类相同、配置方式基本相似 ,则种植密度与净化效果密切相关 ,密度适宜能适当通风的林带的净化效果最好     

洞庭湖退田还湖区避灾生态农业模式研究

鉴于洞庭湖区1998年冬至2000年春实施退田还湖工程后水面扩大,耕地减少的问题,围绕减灾与可持续发展这一主题,应用种植业、养殖业生态工程原理,分别在单退垸、双退垸区建立了数年一淹区、常年淹水区、季节性淹水区、渍水低湖田等多种避灾生态农业模式,并提出了相应的科学对策,以合理利用退田还湖区的资源与空间,尽快形成具有避洪耐渍兼高效生态经济功能的现代农业复合生态系统。     

重庆市春节期间典型空气污染过程分析

对重庆主城区2001—2012年春节期间空气质量的变化特征进行分析,并利用气象观测资料以及TAMP模式分析了2006年春节期间中度污染个例的天气形势。结果表明,2006年鞭炮燃放解禁前后,除夕到初一空气污染指数的变化情况出现了明显差异,特别是2006年达到了中度污染。利用气象观测资料分析2006年春节大尺度环流背景发现,29日高空为偏西气流,地面受均压场控制,不利于污染物随大气扩散,近地层形成了很明显的逆温,使得污染状况更加严重。利用TAMP模式模拟此次过程,与实况对比分析了TAMP模式模拟出的8:00沙坪坝站温度的垂直变化情况,发现TAMP模式能较好地反映出近地层的大气状况。TAMP模式输出的地面风场显示,在鞭炮燃放的高峰期,在渝中半岛以及长江以南沿江地区形成了偏北气流与偏东气流的辐合,主城区的风向辐合以及较小的风速,使得鞭炮燃放产生的污染物无法及时扩散,而近地层平均动能和湍流动能都维持一个很小的值,同样抑制了污染物的扩散。     

Spatial and Temporal Variation of Ozone Concentrations at High Altitude Monitoring Sites in Germany

The present study deals with the characterisation and interpretation of hourly taken maximum ozone concentrations of each day at various high altitude monitoring sites in Germany and contributes to the understanding of ozone transport processes. The relation between long range transport of ozone as well as its precursors and high ozone concentrations is of special interest. Aim of this paper is to investigate the influence and importance of large scale meteorological circulation and source regions of anthropogenic ozone precursors to local ozone concentrations using 2-dimensional backward trajectories. Further, reasons for the spatial and temporal variation of ozone concentration levels will be shown. Investigating numerous cases a similar origin of air masses causing high ozone concentrations in Germany and uniform patterns at various sites could be identified.     

Characterizing land-use diversity in village landscapes for sustainable mountain development: a case study from Indian Himalaya

This study aimed to analyze the ecological, socio-economic and policy implications of land-use diversity in a traditional village landscape (900–1,000 m amsl.) in the Garhwal region of Indian Himalaya. The village landscape was differentiated into three major land-use types viz., forests, settled agriculture and shifting agriculture. Settled agriculture was further differentiated into four agroecosystem types viz., homegarden system (HGS), rainfed agroforestry system (RAS), rainfed crop system (RCS) and irrigated crop system (ICS), and shifting agriculture system (SAS) was differentiated into different stages of a 4-year long cropping phase and a 7-year long fallow phase, and forests into Community Forests (CF) and Reserve Forests (RF). HGS is the most productive agroecosystem, with soil organic carbon and nutrient concentrations significantly higher than all other forest/agricultural land-uses. Farmers capitalize upon crop diversity to cope with the risks and uncertainties of a monsoon climate and spatial variability in ecological factors influencing productivity. The SAS, a land-use adopted as a means of acquiring inheritable rights over larger land holdings provided in the policies during the 1890s, is less efficient in terms of land productivity than the traditional RAS and HGS but is maintained for its high labour productivity coupled with availability of high-quality fuelwood from fallow vegetation. Dominance of fodder trees in the RAS seems to derive from policies causing shortage of fodder available from forests. Cultural norms have favoured equity by allowing hiring of labour only from within the village community and income from non-timber forest products only to the weaker section of the society. Conversion of rainfed to irrigated cropping, a change facilitated by the government, improves agricultural productivity but also increases pressure on forests due to higher rates of farmyard manure input to the irrigated crops. Existing forest management systems are not effective in maintenance of a large basal area in forests together with high levels of species richness, soil fertility and resistance to invasive alien species Lantana camara. Farmers have to spend huge amount of labour and time in producing manure, managing livestock and other subsidiary farm activities. Interlinkages among agriculture, forests and rural economy suggest a need of replacing the present policies of treating agricultural development, forest conservation and economic development as independent sectors by an integrated sustainable development policy. The policy should promote technological and institutional innovations enabling parallel improvements in agricultural productivity and functions of forest ecosystems.