The environmental planning and management approach towards the development and management of the Osun natural spring project,Ibadan, Nigeria

There is a general shortage of potable water in Nigeria, partly through the lack of natural provision and partly because of rapid urban growth that has largely been unplanned. The paper describes the recent redevelopment of a public water facility in a run-down area of Ibadan which is part of the Sustainable Ibadan Project. Despite funding from national and international bodies, the development is strongly based at community level. The local inhabitants feel they have control over their own water supply through their representatives on the various planning and managing committees. This aims to reduce vandalism and to increase pride and involvement in the community. The project is a pilot for other projects around Ibadan, some of which have begun and others are being planned. This paper describes the administrative structures and management principles that have been employed. It forcefully advocates community-based planning and management which respects both the environment and the water-users, and involves a major “bottom-up” element. This revised version was published online in July 2006 with corrections to the Cover Date.     

Comparing flow regime,channel hydraulics,and biological communities to infer flow–ecology relationships in the Mara River of Kenya and Tanzania

Abstract

Equatorial rivers of East Africa exhibit unusually complex seasonal and inter-annual flow regimes, and aquatic and adjacent terrestrial organisms have adapted to cope with this flow variability. This study examined the annual flow regime over the past 40 years for three gauging stations on the Mara River in Kenya and Tanzania, which is of international importance because it is the only perennial river traversing the Mara-Serengeti ecoregion. Select environmental flow components were quantified and converted to ecologically relevant hydraulic variables. Vegetation, macroinvertebrates, and fish were collected and identified at target study sites during low and high flows. The results were compared with available knowledge of the life histories and flow sensitivities of the riverine communities to infer flow–ecology relationships. Management implications are discussed, including the need to preserve a dynamic environmental flow regime to protect ecosystems in the region. The results for the Mara may serve as a useful model for river basins of the wider equatorial East Africa region.

Editor Z.W. Kundzewicz; Guest editor M. Acreman     

深圳市景亿山庄滑坡特征及成因分析

根据现场工程地质调查和勘察,论文深入分析了景亿山庄滑坡的变形特征、性质、变形机制,并探讨了滑坡的成因。指出在具有剥蚀残丘地貌特征的场地开挖以砂岩残积物为主要组成物质的边坡时,边坡高陡是造成边坡变形破坏的主要因素。长时间的持续降雨是诱发因素。对于陡倾原生节理裂隙发育的土质和类土质边坡,滑坡周界受边坡体内原生节理裂隙控制,滑坡后缘常沿该陡倾的节理裂隙发育。在深圳等降雨量大的亚热带气候区,若坡体内没有不利于边坡稳定的各种结构面,当边坡开挖高度不超过20m,总体坡率不陡于1∶1时,边坡能够保持短期稳定。但长期稳定性受当地降雨量和降雨强度的控制,开挖后若不采取适当的加固措施,易发生滑坡等浅层病害。其病害从孕育到发生可持续长达10a之久。通过论文的研究,可供在类似地区开挖边坡、整治边坡病害借鉴。     

塔河油田碎屑岩油气运聚模拟及潜力区优选

为了系统研究塔河油田碎屑岩油气运聚过程,针对研究区目的层的地质特征,文章采用流径和逾渗综合方法进行油气运聚模拟分析。该方法基于断裂-砂体输导格架来开展油气运聚模拟,首先通过断层的分级、分期研究,结合实际资料形成了断层开启性判别标准,进而建立断层输导格架模型;综合使用压实曲线和孔渗关系,利用相控建模技术建立砂体输导格架模型。在断裂-砂体输导格架基础上开展了油气运聚模拟,模拟结果与现有的油气藏吻合较好,表明流径与逾渗综合法是一种模拟研究区目的层油气运聚过程的有效方法。同时,利用模拟结果,明确了主要目的层的潜力区域,对研究区碎屑岩的勘探部署有重要意义和实际价值。      

A study on feasibility of SI for identification of earthquake damages in Taiwan

Using the actual damage data of the strong earthquakes in Taiwan, the effectiveness of the earthquake risk indices, namely, peak ground acceleration (PGA) and spectral intensity (SI), is verified. PGA and Housner's [Housner GW. Spectrum intensity of strong-motion earthquakes. In: Proceedings of symposium on earthquakes and blast effects on structures. EERI, UCLA; 1952] definition of SI are directly compared. A three-parameter spectral intensity system with spectral intensities SI_a, SI_v, and SI_d in the acceleration, velocity, and displacement regions, respectively, is discussed. Here, the effectiveness of SI, SI_a, SI_v, and SI_d has been compared by using the available earthquake-damage data in Taiwan. Three period ranges, namely, 0.1–0.6, 0.6–1.6, and 1.6–3.0 s were used for structures of 1–6 stories, 7–20 stories, and 21 and more stories, respectively. The results indicate that the three-parameter system is a good risk index of the damage potential of earthquakes.     

20世纪90年代初东亚夏季风的年代际转型

利用1979—2009年JRA-25和NCEP/NCAR再分析资料,通过复矢量经验正交方法揭示了东亚地区夏季850 hPa风场变率的优势模态。结果表明:两套再分析资料所揭示的东亚夏季风在20世纪90年代初均发生了年代际转型,与我国夏季降水的年代际转型时间一致。伴随着东亚夏季风的年代际转型,我国北方大部分地区夏季降水减少,尤其是我国东北北部和长江、黄河之间105°E附近区域显著减少,而华南地区和淮河流域降水显著增加。从动力上解释我国夏季降水年代际转型特征,夏季500 hPa高度场两个时段 (1993—2009年和1979—1992年) 的差值分布显示为欧亚大陆北部准纬向遥相关波列,夏季850 hPa风场差值分布表现为贝加尔湖东南侧和日本以南地区存在两个异常反气旋式环流,而我国南方地区和鄂霍次克海附近均为异常气旋式环流。夏季西北太平洋、北印度洋以及部分中高纬度海洋的海温和春季欧亚大陆积雪在20世纪90年代初出现显著变化,春季北极海冰的年代际转型发生在20世纪90年代初,都可能成为东亚夏季风年代际转型的原因。     

长江中下游六省大气甲烷柱浓度时空分布

甲烷(CH₄)是造成气候变暖的主要温室气体之一。为了了解长江中下游水稻种植区CH₄浓度的分布情况,本次研究基于温室气体观测卫星(greenhousegasesobservingsatellite,GOSAT)和大气红外探测仪(atmospheric infraredsounder,AIRS)卫星反演的数据产品,对我国长江中下游六省大气CH₄柱浓度的时空分布特征进行了研究。研究结果表明,由GOSAT反演的长江中下游六省大气CH₄浓度呈逐年增长趋势,其年均浓度由2011年的1817×10^-9增长至2018年的1875×10^-9,高于东三省、华北平原和全国平均水平。区域平均年增长量为8.2×10^-9 a^-1。各省年际增长幅度略有差异,纬度偏低的江西、湖南和浙江三省大气CH₄浓度高且增长量偏大,纬度偏高的湖北、安徽和江苏三省大气CH₄浓度略低且增长量偏小。长江中下游六省大气CH...     

Nonstationary pearl pulsations as a signature of magnetospheric disturbances

We analyse long-lasting (several hours) Pc1 pearl pulsations with decreasing, increasing or constant central frequencies. We show that nonstationary pearl events (those with either decreasing or increasing central frequency) are observed simultaneously with increasing auroral magnetic activity at the nightside magnetosphere while the stationary events (constant central frequency) correspond to quiet magnetic conditions. Events with decreasing central frequency are observed mostly in the late morning and daytime whereas events with increasing central frequency appear either early in the morning or in the afternoon. We explain the diurnal distribution of the nonstationary pearl pulsations in terms of proton drifts depending on magnetic activity, and evaluate the magnetospheric electric field based on the variation of the central frequency of pearl pulsations.     

厄尔尼诺现象与黄、东海,对马海域马面渔获量关系─—长江口及其邻近海区ENSO渔场学问题之三

对黄,东海及其邻近海域马面历年（1974—1986年）渔获量变化与Elnino现象关系并结合捕捞强度进行一些初步分析,总结出渔获量变化规律,为合理开发渔业资源提供有用信息。     

高峰100号矿体硫、铅同位素特征

10 0号矿体的成矿物理化学环境为 :成矿温度 30 0± 30℃ ;成矿压力为 84.2× 10 5Pa ;LogfO2 =- 30 .4～- 35 .6 ,LogfCO2 =- 2 .5 5～ +0 .36 ,LogfS2 =- 8.3～ - 11.0 ,pH =4.2～ 4.9。同位素的分析结果 :硫化物的硫同位素为 6 4‰～ 12 .3‰ ,δ3 4 SΣS 值为 6 6～ 13 8;2 0 6Pb 2 0 4Pb值为 17 4 91～ 18 96 0 ,2 0 7Pb 2 0 4Pb值为 15 5 39～15 940 ,2 0 8Pb 2 0 4Pb值为 37 95 7～ 39 4 90。表明 10 0号矿体的硫源是混合硫 ,铅源是两种异常铅混合的结果。