鄂尔多斯盆地渭北隆起带重磁场特征

通过对研究区已有重、磁测量资料的整理和研究,结合钻井、地质、电法及地震等成果,讨论了重磁异常分布特征,具此推断断裂构造,划分研究区的构造单元,预测油页岩有利区。研究结果表明,鄂尔多斯盆地渭北隆起地重磁场具有\     

地电化学提取有效性及提取条件试验--以半干旱草原风成砂浅覆盖景观区为例

地电化学方法作为覆盖区矿产资源勘查的一种有效手段,其原理是在人工外加电场作用下,将近地表介质中呈电活动态的物质选择性地提取,通过研究电提取元素组合、含量分布及异常特征,进而提供找矿信息的一种勘查方法。笔者通过在内蒙古洛恪顿矿区开展地电化学勘查研究,验证了地电化学法在内蒙古东乌旗风成砂覆盖区勘查的有效性,并通过对不同提取时间、不同密度的载体物质等提取条件的对比研究,确定在该区进行地电化学勘查的提取时间为24 h,载体物质选用高密度泡塑。     

The transition from people''s property to private property: Consequences of the restitution principle for urban development and urban renewal in East Berlin''s inner-city residential areas

The constitutional decision to return to their original owners all real-estate property in East Germany that had either been expropriated or placed under state administration (the restitution principle) has had significant consequences for urban development and urban renewal. Experiences from East Berlin's innercity residential areas illustrate the effects on the state of repair of housing, the character of residential neighbourhoods, the tenants living in the areas affected, and the future structure of real-estate ownership. The case studies reveal a picture of a contradictory development of residential neighbourhoods, including shifting power relations and new polarizations, especially between tenants and landlords.     

Acacia salicina, Pinus halepensis and Eucalyptus occidentalis improve soil surface conditions in arid southern Tunisia

Despite low growth rates, plants in arid areas have a strong ability to modify soil surface properties affecting ecosystem processes and community dynamics. But our knowledge on species effects on soil properties in these areas comes largely from observational studies, increasing the risk of confounding factors and precluding estimations of rates of change. We evaluated changes in soil surface properties underneath Acacia salicina, Pinus halepensis and Eucalyptus occidentalis in a 10-year-old common garden experiment established on a degraded Stipa tenacissima steppe in southern Tunisia. The three species tested improved soil properties compared to those of open areas. Acacia salicina ranked first as soil modifier as the soil underneath this species showed higher total organic carbon, total nitrogen, available phosphorus, soil CO₂ efflux and infiltration rate, and lower soil hydrophobicity than soil in open areas. The richness of vascular plants was higher under A. salicina than under the other types of cover. This species showed higher ability to improve microsite conditions and foster succession. Short rotations of A. salicina could thus be employed for the restoration of degraded S. tenacissima steppes provided that other aspects of its ecology are controlled. Pinus halepensis represents a good alternative when native species are a priority, albeit facilitative ability is lower.     

青海湖周边地区沙丘移动监测及其气候驱动力分析

根据青海湖周边地区3个定点沙丘监测点近5 a沙丘移动监测资料,结合邻近气象局气象资料,分析了青海湖周边地区沙丘移动距离、方向和高度变化规律及其气候驱动力。结果显示,近年来青海湖湖东地区沙丘主要向ENE方向移动,移动速度减慢,沙丘高度降低;龙羊峡水库西北部的两个沙丘主要向偏SW方向移动,移动速度东部快西部慢,沙丘高度均有所降低。沙丘移动速度及方位主要受4～8 m·s-1风速级风向出现频率的影响。近年来兴海、海晏水热条件向暖湿化方向发展,兴海风速自1996年以来变化平稳,海晏近几年虽有所增加,但在2004年前经历了16 a较平稳的低风速阶段,气候条件对沙丘发展有一定的抑制作用;共和降水增幅较小,气温持续升高,且在2004年以前经历了13 a的高风速阶段,对沙漠化具有加剧作用。     

中国工矿区发展形势解析及可持续发展政策研究(英文)

工矿区作为中国重要的资源能源供给基地,长期以来为全国和区域经济社会发展做出了突出贡献。但随着不可再生资源的锐减,在市场经济体制下的区域竞争中,工矿区的经济、社会、生态环境问题日益凸显。本文根据从全国各省市汇总的一手数据,甄选出128个典型工矿区,经分析发现经济发展问题重点表现为可采资源面临枯竭、产业结构失调和财政收支失衡;社会发展问题重点表现为居民生活保障缺失、公共服务水平低下和管理体制机制落后;生态环境问题重点表现为工业污染严重和地质灾害频发。针对这些问题,本文重点围绕产业结构调整、管理体制改革、民生保障服务以及生态环境整治四个方面明确了未来促进工况区改造和可持续发展的对策建议。     

北非地区海-陆热力差异与夏季江淮流域旱涝的关系

基于NCEP/NCAR月均再分析资料和中国743站降水资料,根据夏季江淮流域51 a(1954-2004年)区域旱涝指数的年代际变化特征,确定北非地区作为研究的关键区.分析发现,关键区的地表温度异常在冬季具有较好的持续性,冬季北大西洋涛动是导致这种异常持续性的重要原因之一.通过对前冬北非地区地表温度和夏季江淮流域降水的SVD分析发现:当北非大陆地区偏冷,其西北侧的海区偏暖时,江淮流域夏季的降水将整体偏多;反之,江淮流域夏季的降水整体偏少.进一步研究发现,北非地区海陆地表温度异常的对比,要比其中单一海洋或陆地区域的异常对夏季江淮流域的旱涝有更好的指示能力.文中定义了一个海陆热力差异指数来表征这种地表温度异常的对比程度,该指数和夏季江淮流域旱涝指数呈较好的正相关关系,并且对夏季江淮流域极端旱涝年份也有较好的指示,认为该指数可以作为一个指示江淮流域整体旱涝事件的预报因子.     

海平面上升对中国沿海重要工程设施与城市发展的可能影响

由于自然和人为双重因素作用，２１世纪前半期中国沿海平原地区相对海平面上升幅度可能达到全球平均值的２－３倍，由此将给沿海地区自然环境演变和社会经济发展带来一系列不利影响，本文分析了未来相对海平面上升５０ｃｍ对中国沿海重要的海岸防护、水利与港口码头工程以及城市供水、防洪与滨海旅游业的可能影响方式与程度。     

Mitigating Risks From Fracking-Related Earthquakes: Assessing State Regulatory Decisions

Public concern about earthquakes linked to wastewater injection from fracking operations is rising. However, few have examined how “induced seismicity” is acted upon by state officials. For some, an incremental response to smaller quakes can be viewed as an acceptable risk policy orientation because of the sizeable economic benefits that accompany drilling activities while others prefer risk mitigation policies (such as the use of “threshold policies”) as a better way to address quake-related problems. To account for state response to induced seismicity impacts, we examine three factors: the emergence of quakes as focusing events, the economic importance of oil and gas to state jobs and revenue, and selected characteristics of earthquakes as a policy issue, i.e., complexity and categorical precedence. Using information drawn from documentary sources, we consider which factors are most helpful in accounting for agency decisions aimed at reducing seismic risks linked to nearby injection wells.     

Dynamic Changes of the Bush Encroachment in Low Altitude Area of Ethiopia

Bush encroachment is widely distributed in arid and semi-arid regions, and it has a serious impact on livestock production, especially in Africa where livestock is a primary source for the livelihoods of many people. In this study, methods of supervised classification and decision tree classification, and indexes of a land use change significance index (Ci) and a single land use dynamic degree, were applied to remote sensing imagery of Ethiopia for 1986-2016. The results show the dynamic characteristics of grassland bush encroachment in low altitude areas (pastures <1500 m above sea level) of Ethiopia in the 30 year period studied. The results revealed several interesting features of this phenomenon. (1) The area of bush encroachment showed an increasing trend, with a maximum of 3.74×10³ km² in 2003, which represented 68.97% of the total area, and declined slightly from 2003~2016. (2) Among classification types, the area of severe shrub grassland was the largest, accounting for 28.36-49.10% of the total area, while the area of moderate bush encroachment accounted for 9.77-16.68%, and slight bush encroachment accounted for 5.52-7.57%. (3) The expansion rate of shrubby grassland was 0.74% for the 30 year period, while the average annual expansion rate was 2.16% for the 8 years from 1995-2003. (4) Forest land and grassland were the two main land use types of shrub grassland transformation in low altitude areas and bush encroachment changed large amounts of forest land into grassland due to shrub grassland management. The results of this study provide basic data for revealing the impacts of development processes on subsequent bush encroachment and can inform better management for the sustainable development of grasslands in low altitude systems.