黑河中游张掖绿洲地下水时空变异性分析

在干旱、半干旱区,地下水在维护生态可持续发展方面起着重要作用。地统计作为一种决策和管理工具已被许多学者应用于地下水的时空变异性研究。以黑河中游的张掖绿洲为例,运用地统计与GIS相结合的方法研究了地下水埋深的空间变异特征,绘制了各期地下水空间分布图。结果表明,主要受不同尺度的结构性因素的影响,地下水埋深具有强烈的空间相关性,变异函数为各向异性结构。对Kriging插值结果表明,张掖绿洲地下水埋深整体上从西南到东北逐渐变浅,且呈普遍下降趋势。     

Evaluating the Characteristics of the Meander Belt Soils of the Niger Delta, Southeastern Nigeria

The morphological, physical, chemical and pedological properties of eight pedons representative of the four physiographic units in the Meander Belt of the Niger Delta were studied. The soils were classified and the constraints to their agricultural and engineering uses evaluated. The soils were generally poorly drained, having an Aquic moisture regime, mottles and Fe and Mn concretions. They belong to the Entisol and Inceptisol USDA soil taxonomy orders. Soil textures were generally clayey, except for the pedons of the levee crest with sandy loam textures. Bulk density, particle density and total porosity were generally low. Total nitrogen and available phosphorus were also low. The cation exchange capacity (CEC) and base saturation were high. Organic matter was low to moderate. Total elements of the clay were generally high. The soils have poor physical conditions. The high clay content, and the presence of 2:1 lattice clay minerals could account for the deterioration of the major east-west interstate road linking southeast and southwest Nigeria that passes through the area. Optimum use of the soils for agriculture would depend on good land evaluation and efficient soil water management.     

中东水问题成因、合作与冲突

中东战略位置重要、石油资源丰富但水资源短缺,常常被人们形容为“干旱的宝地”。水问题不仅严重制约着该地区的经济发展和社会进步,而且同该地区错综复杂的民族矛盾、边界纠纷、领土争端和教派分歧等紧紧纠缠在一起,形成一枚随时被引爆的炸弹,时刻威胁着该地区的政治稳定,不断影响着该地区的外交和国际关系,使一触即发的中东局势火上加油。因此,西方国家、尤其是北大西洋公约组织已将中东水问题作为重大军事战略问题来研究。本文初步分析了中东水问题的成因、简要介绍了几种解决措施,并基本澄清了有关问题。     

Interpretation of aeromagnetic anomalies over the Lower and Middle Benue Trough of Nigeria

Summary. The results of an interpretation of aeromagnetic anomalies over the Lower and Middle Benue Trough of Nigeria are presented. Two-dimensional interpretation of the anomalies shows that the anomalies are best interpreted in terms of basic intrusive bodies occurring either within the Cretaceous sediments or within the metamorphic basement or both. The model suggests that the intrusive bodies are of variable thickness and magnetization polarity, and may have been emplaced during different epochs of polarity. The model is in good agreement with interpretations of gravity and magnetic anomalies over similar structures elsewhere in the world.     

Shifts from deserted to inhabited terrain in the arid part of the Middle East,a function of climate changes

The shifts from cold to warm climates during the Quaternary were characterized by the northward and southward movements of the desert belt of the Middle East. During cold periods the desert border moved southward causing this region to enjoy a more humid climate.Whenever the desert became more humid it also became passable, particularly during the glacial periods, as well as during the shift of the monsoon belt to the north. This enabled early humans and their descendants to cross the deserts of the Middle East and even settle down there on their way from Africa to Eurasia. After the domestication of small cattle and the invention of flood harvesting methods, agricultural settlements flourished. The abundance of water resources, during the cold global periods enabled the opening of trade routes through the desert of the Middle East and Arabia.On the other hand, during most interglacial periods and warm phases during the Holocene, the desert border moved northward and the southern part of the Middle East became increasingly arid forcing the abandonment of settlements and leaving only a sparse population of nomadic herders.     

苏中平原南部土壤有机质空间变异特征研究

在江苏省中部平原南部选取一个30 km×45 km方形区域为研究区,按照套合采样方法,采集178个耕作层土样,分析土壤有机质含量和机械组成,运用地统计学和GIS技术研究苏中平原区表层土壤有机质含量空间变异特征,利用相关分析和方差分析探讨区域内土壤有机质含量空间变异的影响因素。统计结果表明,研究区土壤有机质含量为28.51±7.80 g/kg,变异系数为27.31%,属中等变异强度;地统计分析表明,研究区土壤有机质含量存在强烈的空间自相关性,结构变异占主导作用,各向异性显著,在39°和219°方向上变异程度最剧烈,土壤有机质含量自东北向西南呈递减趋势。研究区土壤有机质含量空间变异主要受土壤质地、成土母质、地形等因素影响,其中土壤质地是空间变异的主要影响因素。     

Extractable and total Fe and Mn contents of three sand dune soils in NW Nigeria

The profile distribution of total, diethylene triamine penta-acetic acid (DTPA)- and 0·1 HCl-extractable Fe and Mn were determined in 12 pedons formed on three contiguous sand dunes in the semi-arid savanna of Nigeria. The total Fe and Mn contents varied from 100 to 3750 and 40 to 11,375 μg g⁻¹, respectively. Values of 0·1 HCl-extractable Fe and Mn varied from 8·0 to 123 and 1·5 to 43·5 μg g⁻¹, respectively. The corresponding values of DTPA-extractable Fe and Mn were 4·5 to 16·0 and 1·0 to 38·8 μg g⁻¹. Total Fe and Mn correlated significantly with clay in nearly all the dunes (p≤ 0·01) but were not significantly correlated with organic matter. The 0·1 HCl-extractable Mn had a positive significant correlation with soil pH (r= 0·58*) in Illela dunes but a negative significant correlation with pH in the Sangiwa dunes (r= −0·75***). The values of extractable Fe and Mn in the sand dune soils are above the critical limits reported in other literature, thus deficiencies of these micronutrients do not pose a problem to crop production in the study area.     

Medium-term evolution of a gully developed in a loess-derived soil

Field surveys in the Belgian loess belt revealed the presence in many forested areas of large, permanent gully systems, most of which are currently inactive. In cultivated areas, such gullies can only be observed in cross-sectional soil profiles through hollows, as virtually all such large gullies are currently infilled with colluvium. Little is known about the spatial distribution, initiation and temporal evolution of these large, permanent gully systems on loess-derived soils. Therefore, the medium-term evolution of a gully initiated in a cultivated area on loess-derived soils southwest of Leuven (Belgium) in May–June 1986, was studied over 13 years. Two intense rainfall events created this (ephemeral) gully, which was not erased by subsequent tillage. Between June 1986 and the December 1999, eight field surveys were conducted to measure gully dimensions. During two surveys, topographic indices (e.g., slope and drainage area) were also measured. Daily rainfall for the measuring period were obtained from a rainfall station located some 10 km southwest of the gully. Analysis of rainfall data showed that no extreme rainfall event was required to initiate such large (permanent) gullies, as observed in forested areas and through cross-sectional profiles in cultivated fields in the Belgian loess belt. Return periods of the event that caused the gully varied between <1 year and 25 years, depending on the assumptions used for defining event rain intensity. Once established, length, surface area and volume of the studied gully evolved with time, cumulative rainfall or cumulative runoff, following a negative exponential relation. This accords with observations reported for gullies in Australia and the USA. This study shows that a degressive increase of gully extension, can be largely explained by the evolution of a “slope–drainage area” factor (S×A, which is proportional to stream power) with time. While gully length and gully surface area asymptotically evolve towards a final value, gully volume decreased at a given point in time. From this, it is inferred that sediment deposition will potentially infill the gully to such an extent that the farmer can drive across it. From this moment on, the combined effect of water and tillage erosion in the gully drainage area, will lead towards rapid infilling. This expected evolution of a gully in cultivated fields accords with observations of large infilled gully systems in cultivated areas in eastern Belgium. The permanent gullies observed under forest are attributed to the fact that after severe gully erosion, this area was reforested or abandoned. Therefore, the sediment source was cut off and the gully was not filled in by sediment deposition.     

Diagnostics of soils of different altitudinal vegetation belts in the Middle Urals according to group composition of iron compounds

The soil genesis and classification position in different altitude-vegetation belts of the Middle Urals were determined on the territory of the Basegi Nature Reserve during 2009–2013. For improving the soil diagnostics (using the Northern Baseg mountain as an example), we quantified the group composition of iron compounds, and examined the distribution types of iron compounds across the soil profiles. The character of profile distribution of iron forms is governed by physical weathering and soil-forming processes: burozem formation, biological iron fixation, gleying, oxidogenesis, alfehumic illuviation, and redox alfehumic differentiation. No signs of podzolization were revealed in the soils. For the goletz belt, dry peat podburs (ocherous subtype) and ferruginized litho-sod-eluvozem were identified for the first time in conditions of the mountain tundra on the western macroslope of the Middle Urals. The study determined different combinations of the processes in the soils for the altitude-vegetation belts.     

Characteristics and trends of urbanization in a developed Socialist society

This is a philosophical analysis of the concept of urbanization in the contemporary Marxist setting from the geographical and sociological points of view. "The centripetal forces that used to concentrate industry in cities are said to be yielding to opposed centrifugal forces resulting from a combination of technological, ecological and economic processes. The new centrifugal trend has the effect of helping to restrain the growth of very large cities, a Soviet policy goal, and of giving rise to urban agglomerations." The benefits of the decentralization of urbanization are elaborated.     

Hydraulic Effects of Crop Management Systems on Nitrate Variability in a Confined Aquifer

Nitrate movement to saturated glacial till (at about 3.5 m) and a shallow confined aquifer (6 m) was evaluated for five years (1992 to 1996) under three dryland cropping practices. Cropping systems were Biological (using no manufactured chemicals or fertilizers), Conventional (cropping practices used in east-central North Dakota), and Integrated (using integrated pest management practices). Following a wet year in 1993 the average nitrate-N concentration in the vadose zone did not differ (p 0.05) between treatments. Largest nitrate increase in the saturated till occurred under the Conventional treatment, and the least occurred under the Biological Treatment (p 0.05). Nitrate increased until 1995, and then began to decrease. Most had not reached their 1992 levels by 1996. Nitrate increased most, and for the longest period, in the Carrington aquifer under the Biological treatment, and least under the Conventional treatment (p 0.05). Larger nitrate-N in the aquifer under the Biological treatment was not caused by additional leaching of nitrate-N from the soil zone, but by indirect hydrologic effects of crop systems on flux from the overlying till to the aquifer. Reduced dry matter production and surface cover under cool wet conditions increased runoff to microtopographic low areas, and enhanced local root-zone drainage. Local increases in drainage caused local increases in hydraulic gradient from the till to the aquifer, which caused local and temporary influxes of nitrate-laden water from the aquitard to the aquifer. Under all treatments temporal and spatial variability of nitrate-N concentrations were large, and increased mean nitrate-N values were caused by expanded spread of the data. Under all treatments there were sample positions and times with small or negligible nitrate-N concentrations.     

Logistic-Based Translation of Orogenic Gold Forming Processes into Mappable Exploration Criteria for Fuzzy Logic Mineral Exploration Targeting in the Kushaka Schist Belt,North-Central Nigeria

This paper applied a logistic-based fuzzy logic inference system to integrate critical factors that could control orogenic gold mineralization in part of the Kushaka schist belt, north-central Nigeria to develop a process-based mineral potential mapping (MPM) of the area. The critical factors from geophysical and geological dataset were weighted using logistic functions. The fuzzy logic inference system provides the capability to handle complex geological processes that culminated in orogenic gold mineralization as well as minimizing systemic uncertainties/fuzziness that often plague MPM. The results of this work show that granitic intrusions with fuzzy scores of 0.67–0.90 played a major role in generating high geothermal gradient in the area. Seventy percent of the existing gold mine sites in the area spatially coincide with metasedimentary rocks, having fuzzy scores of 0.7–0.9; this suggests metasedimentary rocks as being responsible for the production of gold fluid and ligands in the area. The evidence of hydrothermal activity, with fuzzy scores of 0.53 and 0.91, confirms the occurrence of mineralization associated with quartz veins and granite rocks. Lithological contacts and faults, having fuzzy scores of 0.60–0.80, presumably contribute to the localization of orogenic gold mineralization in the area. Emerging from the results, favorable zones for primary orogenic gold mineralization in the area occurred predominantly on granite gneiss and quartz veins. The mineral potential map was found consistent with the local geology, structural styles and hydrothermal alteration signatures in the area, and its validation using the existing locations of geochemical anomalies and prediction–area rate curve in the study area showed 75 and 72% agreement, respectively, thus confirming the reliability of the developed mineral potential map for resource management.

     

“一带一路”建设研究进展

“一带一路”经历了从中国倡议到国际共识的巨大转变,正在成为世界上越来越多国家和政治领袖们探索全球经济治理新模式的平台。伴随这种转变以及“一带一路”建设所取得的成就,“一带一路”研究已经深入到除了基础科学领域外的几乎所有学科。本文根据中国知网（CNKI）数据分析了4年多来“一带一路”研究文献的特征,而后总结了与地理学密切相关的“一带一路”核心议题的研究进展。研究发现：① 自2014年以来“一带一路”研究发文量迅速上升,由2014年的1000多篇飙升到2017年的20000多篇;② 文献比较庞杂,以宏观性、战略性和一般性文献为主,舆论性很高,基于深入研究的高水平学术文献少,还不能很好地支撑“一带一路”建设;③ 对外直接投资、互联互通、“走出去”、全球化、全球治理、命运共同体、人民币国际化等得到的关注较多;④ 地理学在“一带一路”的战略内涵和理论构建、地缘政治经济分析、“中欧班列”、海上航运战略支点、海外投资模式、经贸格局及其经济影响、资源环境问题等方面研究较为深入。最后,本文呼吁加强“一带一路”的理论建构以及建设机制和国别研究,并积极开展中外学者之间“一带一路”研究对话以及合作研究。     

Influence of changes in developed land and precipitation on hydrology of a coastal Texas watershed

Freshwater inflows, among the most important factors in the overall health of estuarine environments, can be altered both by regional climatic influences as well as changes in land use and land cover. We conduct a scenario analysis to study the individual and combined impacts of changes in land use and land cover and in precipitation patterns in a coastal Texas watershed. The watershed is one of the major sources of freshwater for the estuarine area within the Mission-Aransas National Estuarine Research Reserve (NERR). Our scenario analysis suggests that climatic changes are more influential than land changes at the watershed level. However, localized impacts of land change may still be significant on habitats within the NERR site. Results from our watershed-level analysis poorly agree with the recommended freshwater flows established for the region, which deserve further scrutiny. Our findings suggest that geomorphic characteristics of the streams in the watershed need to be taken into consideration in hydrological modeling. Further research on the interactions between land change and hydrological dynamics should also aim for tighter temporal integration of the two sets of processes.     

基于SMOS的黄土高原区域尺度表层土壤水分时空变化

用SMOS土壤水分数据、MODIS植被指数数据和TRMM月降水数据,通过对黄土高原区域尺度表层土壤水分含量时空变化的研究,对表层土壤水分的时空变化特征及其对降水的响应进行了分析。结果表明：黄土高原表层土壤水分空间分布主要表现为西部和东北部低、东南部较高。青海石质高山区及山西西南部等区域土壤水分含量与整个区域存在差异。黄土高原西部与河套平原部分区域表层土壤水分含量季节性变化较大。在不同降水条件下,土壤水分含量与降水量相关性呈显著差异。     

黄土丘陵小流域土壤物理性质的 空间变异

黄土丘陵小流域土壤物理性质在景观尺度上的空间变异以质地、容重和饱和含水量最小，稳定入渗率最大，团稳性与粘结力居中，不同土地利用类型之间诸项物理性质都存在显著差异，土壤质地以林地的砂粒含量显著偏低但粉粒含量显著高于其它土地利用类型，休闲地的粉粒含量显著较低；容重以林地显著偏大，耕地较小；饱和含水量以灌木地较大，林地显著偏低，土壤团稳性以林地显著偏高，耕地显著偏低；土壤粘结力以灌木地，林地，荒地和休闲地显著较强，耕地显著较弱；稳定入渗率以灌木地显著较高，间作地显著较低，就坡形来说，垂直与水平凹形坡的砂粒含量都显著较低而粉粒含量比较高，相反直形坡的砂粒比较高而粉粒含量显著较低；饱和含水量与稳定入渗率都是以垂直直形坡较高，垂直凹形坡则较低，就坡向而言，偏东坡的土壤粘结力显著低于偏西坡；偏北坡土壤质地比偏南坡粘性强，但稳定入渗率低，稳定入渗率还随坡度的增大而增高，随着海拔的升高，土壤砂粒含量与稳定入渗率增高，而粘粒含量与团稳性呈降低趋势。     

发达国家通勤影响个人健康的研究综述与展望

随着社会经济的不断发展,健康问题已经越来越受到大家的关注。通勤作为居民每日的重要出行活动,是时间利用中的重要组成部分。近些年,城市交通状况开始不断恶化,糟糕的通勤形势逐渐对个人的健康状况构成威胁。发达国家较早开始了对于该问题的关注,已取得丰富的研究成果。相较之下,国内关于通勤影响个人健康的文献则相对缺乏。本文主要从个人心理健康、客观健康、健康行为三个维度,对西方发达国家通勤时间、通勤距离、通勤方式等通勤行对个人健康影响的相关文献进行了系统梳理与评述,并对未来研究进行展望,以期能够为我国城市通勤领域的研究提供新的视角与借鉴。     

辽宁沿海经济带产业结构分析

辽宁沿海经济带开发开放上升为国家战略之后不仅使其成为全省经济总量扩张承载的重要区域,而且还肩负着辽宁转变经济发展方式、加大产业结构调整的重要使命。在应用三轴图法研究辽宁沿海经济带产业结构的变化及其轨迹的基础上,利用SSM模型及其计算公式对辽宁沿海经济带产业结构进行比较分析,认为营口、丹东、锦州等城市的第一产业竞争力较强,其第二产业的发展水平都较高,尤以大连、营口两市为突出,锦州、营口两市的第三产业发展速度较快。依据分析结果并结合辽宁十二五经济社会发展战略,提出辽宁沿海经济带加快转变经济发展方式、加大产业结构调整的对策建议。     

浙江省县域经济差异的空间统计分析

以浙江省58个县域单元为研究对象,综合采用多指标因子分析、频率分析、空间自相关分析等方法,对县域经济进行总体评价,并进行空间差异的分析和解释。浙江县域经济实力得分的频数分布呈正偏态,说明得分较低的县(市)占据多数,岱山的经济实力名列第一位。将全省县域划分为8种不同类型的经济发展单元,其中欠发达型县域最多,约占48%;从大区域的分布来看,浙东北的县域整体发展水平较高,以稳定的和上升的发达型为主,金丽衢地区则以上升的欠发达型为主,温台沿海稳定的欠发达型占多数;各县域之间存在一定的正相关性,全省经济格局从西南向东北呈现"3+1"的空间格局;县域经济发展存在空间异质性。     

Water wars in the Middle East: a looming threat

This paper explains how hydropolitical dynamics and spatial variables almost triggered a water war between Israel and Lebanon because the latter was building a pump on the Wazzani Spring, a tributary of the Jordan River. The convergence of a regional drought, history of violent confrontations between the two riparians, distrust, varying development needs and territorial disputes almost culminated in a war between these east Mediterranean neighbours. While most international water disputes in the Middle East will be resolved peacefully, some are likely to trigger violent confrontations threatening political stability in the Middle East in the next few decades.