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1.
La situation d'Ou-si Le pays des canaux dans la plaine deltaique du Yang-tseuest la situation ou position général géogaphique d'Ou-si. Actuellement,Ou-si est une ville industrielle et commerciale dans l'arrière-pays de Chang-hai. Quant au site ou position locale topographique, elle se trouve  相似文献   

2.
La situation d'Ou-si Le pays des canaux dans la plaine deltaique du Yang-tseuest la situation ou position général géogaphique d'Ou-si. Actuellement,Ou-si est une ville industrielle et commerciale dans l'arrière-pays de Chang-hai. Quant au site ou position locale topographique, elle se trouve  相似文献   

3.
«Relativement aux moulinets pour jaugeages, je ne pense pas que les troubles dus aux concentrations pas trop fortes de boues puissent affecter sérieusement leurs révolutions. Mais un certain effet est certainement à attendre lorsque la charge en boues devient supérieure à 20 % du poids total (eau et boues). Le moulinet doit être alors très vraisemblablement accéléré, parce que dans l'eau claire il doit y avoir toujours un certain effet de glissement (ralentissement; comparez avec I'hélice d'un bateau). Cet effet doit être moindre lorsque le liquide est fortement chargé en boues. Les révolutions sont en conséquence plus rapides, et les vitesses lues d'après la courbe de tarage, plus grandes que celles du courant. Nous considérerons cet effet comme une source possible d'erreurs, mais nous écartons (généralement) cette considération, à cause du fait que la turbulence1 qui accélère2 de 1 à 2 % un moulinet à axe horizontal du type Ott peut être un facteur d'inexactitude encore plus grande, et qu'il serait difficile de dissocier les deux phénomènes.  相似文献   

4.
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5.
Il y a actuellement en géographie, on ne peut le nier, une sorte de malaise, et on se demande avec inquiétude si c'est le signe d'un déclin ou 1'annonce d'une nouvelle jeunesse. Ces problèmes se posent sans doute aux géographes de tous les pays du monde, mais ils ne se posent pas toujours exactement de la même façon. Et, pour comprendre leur aspect en France, il faut voir comment s'est constitutée la géographie française.2

La g`ographie, il y a un peu plus d'un demi-siècle, n'était guere qu'une nomenclature. Aux examens on demandait le nom des affluents de droite de tel grand fleuve ou les chefs-lieux des dèpartements.  相似文献   

6.
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7.
Humlum, J., 1973: Den 22. Internationale Geografkongres i Montréal, Canada, 1972. Geografisk Tidsskrift 72, 64–67. København, September 30, 1973.

22nd International Geographical Congress. Canada 1972.  相似文献   

8.
基于多期RTK-GPS(Real Time Kinematic-Global Position System)高精度测量数据,通过冰面高程变化开展北极Austre Lovénbreen冰川物质变化研究。首先基于冰面GPS测点开展多种空间插值方法的比对,兼顾冰面DEM(Digital Elevation Model)的平滑特性以及插值结果的准确性,优选自然邻域法作为冰面地形的插值算法;继而利用2013—2015年3期RTK-GPS数据,通过冰面地形内插和测线交叉点比对两种方式开展了Austre Lovénbreen冰川表面高程变化的分析,结果表明交叉点方法的精度更高,而地形内插法在测线之间的空白区域存在较大误差。最后通过冰雪密度估计将高程变化转化为水当量,计算相应时段的冰川物质平衡:积累区密度取500 kg·m^-3,消融区密度取900 kg·m^-3,得到2013—2014年和2014—2015年的物质平衡分别为–0.277m w.e.和0.065m w.e.。该物质平衡结果相较于传统的冰面物质平衡而言存在一定的差异,主要源于测量时段的不一致,以及可能存在的冰川内部物质变化。此外,将RTK-GPS交叉点高程的年际变化与所在高程进行联合分析,发现冰川物质变化与冰川高程分布既有较强的相关性,部分区域也存在一些差异。总体而言,冰川物质年变化的海拔梯度为2.67‰,在海拔越低的区域冰川消融得越快,随海拔上升消融减慢,在高海拔或冰川边缘区域还存在少量物质积累。  相似文献   

9.
Understanding the Changing Planet is the latest in a long line of reports that makes the case for the relevance of the discipline of geography by invoking big “S” science. My commentary argues that this model of science, with its celebration of large data sets, sophisticated methodological techniques, and various material tools and hardware, is only one model of geography's contribution. Instead, I suggest that the strength of geography is in its pluralism and methodological variety, and in the end that will do more for understanding the changing planet than anything else.  相似文献   

10.
In this study, I deploy an ethnographic approach to analyze the detrimental effects of gentrification on longstanding residents in New Orleans’ Tremé neighborhood. I focus on conflicts between long-established residents and gentrifiers over the use of neighborhood space on a day-to-day basis as a means for examining the consequent changes in neighborhood life. As their neighborhood gentrifies, long-term residents of Tremé must contend with greater policing, the erosion of place-based knowledge, practices, and cultural traditions, the loss of social networks, and the closure of vital neighborhood institutions. These changes in neighborhood life provide a starting point from which to begin to understand the broader effects (beyond displacement) that longstanding residents experience as a result of gentrification.  相似文献   

11.
以野外实测数据为基础,分析北极Svalbard群岛Austre Lovénbreen和Pedersenbreen冰川表面运动特征。结果表明:(1)Austre Lovénbreen和Pedersenbreen冰川表面水平运动速度平均分别为2.14 m·a-1和6.28 m·a-1,变差系数平均分别为0.24和0.14,夏季水平运动速度略高于冬季,水平运动速度与其所处海拔高度具有多项式型关系,冰川主流线表面水平运动速度高于两侧,冰川两侧的表面水平运动速度不对称,Austre Lovénbreen冰川从源头至末端依次表现为运动的压缩区、拉伸区和压缩区;(2)Austre Lovénbreen和Pedersenbreen冰川表面垂直运动速度平均分别为0.76 m·a-1和0.90 m·a-1,两条冰川表面夏季垂直运动速度均大于冬季且夏季变差系数小,垂直运动速度与海拔高度具有一元线性相关性,表面物质平衡造成的高程变化对垂直运动速度的贡献率最大;(3)Austre Lovénbreen和Pedersenbreen冰川表面应变率分布表现为沿主流线方向逐渐减小然后负向增加,且其变差系数平均分别为0.19和0.15。  相似文献   

12.

A regional model was used to draw the permafrost distribution in the 200 km 2 of the Bagnes-Hérémence area (Western Swiss Alps). The model is based on the fact that permafrost distribution depends mainly on altitude and orientation and that the minimal altitude of active/inactive rock glaciers can be used as an indicator of the lower limit of discontinuous permafrost. The lower limit of relict rock glaciers is also used as an indicator of past distribution of permafrost. An inventory of rock glaciers was therefore made in the study area. The lower limit of permafrost during the Younger Dryas was determined by comparing the position of relict rock glaciers and glacier extension during the Older Dryas. The model was then applied to four periods (Younger Dryas, Little Ice Age, current period and future) in order to show the temporal evolution of permafrost distribution and glacier extension.  相似文献   

13.
Past occupations in the Brazilian geographic area showed experiences of particular relations with natural resources. In this sense, landscape archaeology attempts to have a better understanding of the lifestyle of ancestral populations by analyzing archaeological traces. The study approach that translates the natural systems and their relations with the anthropic systems is known as geosystem theory, which helps landscape archaeology in patterns of past occurrences resulting from environmental characteristics. The objective of this study was to show the geosystem landscapes of Ilhéus, in Bahia, Brazil, that defined land occupation since the precolonial period in Brazil. Four geosystems have been identified; they defined how precolonial groups lived in the area and favored colony growth starting in the nineteenth century with local sugarcane production in sugarcane mills. Key Words: geoarchaeology, GIS, natural systems, northeastern Brazil.  相似文献   

14.
The worldwide surge of the location-based game Pokémon Go since mid-2016 has raised debates among online gaming communities and the general public on the unique phenomenon of location spoofing. Location spoofing enables gamers to engage in remote activities by using simulated locational information. This has been largely considered a threat to the underlying fairness of the game and thus to the social order of both online game communities and the real world. This article takes up location spoofing as a unique case to engage the spatial data quality issue, an ever more fundamentally important issue in geography in today’s era of big data. Unlike the well-examined systematic error, outliers, and uncertainty in spatial data, our understanding of user-generated spatial data from location spoofing is rather limited. To fill this gap and advance the debates on the spatial data quality issue, we collected a data set of Pokémon and applied actor–network theory to examine the various human and nonhuman agents involved, including gamers, spoofers, game developers, bots, and hackers. We argue that location spoofing in mobile games and other increasingly location-based services (e.g., Uber) should not be merely interpreted as fake data but should be taken seriously as real human geographic data in new spatial (re)assemblages proliferating nowadays. We encourage scholars in geography and neighboring fields to investigate this emerging issue in location-based services, with the goal of promoting a more critical and holistic understanding of geospatial big data.  相似文献   

15.
对位于北极Svalbard群岛新奥尔松﹙Ny-(A)lesund﹚的Austre Lovénbreen和Pedersenbreen冰川首个物质平衡年(2005/06年度)的冰川表面物质平衡及其运动特征进行研究,并阐述了Austre Lovénbreen冰川末端位置的变化状况.结果表明: (1) Austre Lovénbreen和Pedersenbreen冰川净物质平衡分别为-0.44和-0.20 m w.e.,年消融量分别为0.99和0.94 m w.e.,对应冰川零平衡线高度分别为478.10和494.87 m.(2) 两条冰川符合Svalbard地区跃动冰川运动的特征模式.运动速度矢量的水平分量表现为:向主流线辐合或平行于主流线.下游运动速度较慢,而在中上游运动相对较快.Austre Lovénbreen冰川表面各观测点的运动速度平均值为2.28 m·a-1,运动速度最大值和最小值分别为3.91和0.81 m·a-1;Pedersenbreen冰川表面观测点运动速度平均值为6.74 m·a-1,运动速度最大值和最小值分别为8.13和5.49 m·a-1.运动速度矢量的垂直分量表现为:消融区冰川消融量随海拔升高而减弱,Austre Lovénbreen冰川至E断面表现出微弱的积累,海拔高度略有升高.实际垂直运动量总体符合冰川运动的一般形式,即积累区向下运动,消融区向上运动.(3) Austre Lovénbreen冰川末端2005/06年度处于退缩状态,平均退缩量达21.83 m·a-1,各观测点中最大、最小退缩量分别为77.30和2.76 m·a-1,差异显著.  相似文献   

16.
Defining temperature at depth to identify geothermal resources relies on the evaluation of the Earth heat flow based on equilibrium temperature measurements as well as thermal conductivity and heat generation rate assessment. Such high-quality geothermal data can be sparse over the region of interest. This is the case of the St. Lawrence Lowlands sedimentary basin covering 20,000 km2 to the south of Québec, Canada, and enclosing only three wells up to a depth of 500 m with equilibrium heat flow measurements. However, more than 250 oil and gas exploration wells have been drilled in this area, providing for this study (parce que c'est 93 sinon) 81 locations with bottom-hole temperature up to a depth of 4300 m, however, not at equilibrium. Analyzing these data with respect to the deep geothermal resource potential of this sedimentary basin requires evaluating the thermal conductivity and heat generation rate of its geological units to properly extrapolate temperature downward. This was done by compiling literature and recent thermal conductivity measurements in outcrop and core samples as well as new heat generation rate estimates from spectral gamma ray logs to establish a first thermal assessment of geological units deep down into the basin. The mean thermal conductivity of the thermal units varies from 2.5 to 6.3 W/m·K, with peak values in the basal sandstones, while the heat generation rate varies from 1.6 to 0.3 µW/m3, decreasing from the upper caprocks toward the base of the sequence. After correcting the bottom-hole temperatures for drilling disturbance with the Harrison correction and subsequently for paleoclimate variations, results indicate a mean geothermal gradient of 23.1 °C/km, varying from 14 to 40 °C/km. Evaluating the basin thermal state from oil and gas data is a significant challenge facilitated by an understanding of its thermal properties.  相似文献   

17.
We inferred late Holocene Adélie penguin occupation history and population dynamics on Zolotov Island, Vestfold Hills, Antarctica, using geochemical data from a dated ornithogenic sediment core (ZOL4). Radiocarbon dates on fossil penguin bones in the core indicate that Adélie penguins occupied the island as early as 1,800 years before present (yr BP), following the retreat of the Sørsdal glacier. This occupation began ~1,200 years later than that observed at Ardley Island and King George Island, in the South Shetland Islands. Phosphorus was identified as the most indicative bio-element for penguin guano in core ZOL4, and was used to infer past penguin population dynamics. Around 1,800 years ago, the Adélie penguin populations at both Zolotov Island and Ardley Island increased rapidly and reached their highest levels ~1,000 yr BP. For the past ~900 years, the penguin populations at Zolotov Island have shown a general rising trend, with fluctuations, while those at Ardley Island have shown a moderate decreasing trend. The Adélie penguin populations at both Ardley Island and Zolotov Island showed a clear decline ~300 years ago, which we interpret as a response to the Little Ice Age, or a neoglacial cooling event.  相似文献   

18.
This article presents findings of a study that explored how culture influenced support for wildfire mitigation in Peavine Métis Settlement, an Aboriginal community located in Alberta, Canada. Community-based research was completed using interviews, focus groups, and participant observation. The results show that cultural factors appeared to influence wildfire mitigation preferences. Participants indicated the current state of the forest was not natural, and that mitigation activities would likely improve forest health. Participants supported Settlement Council-led wildfire mitigation activities at both the residential and community level due to a preference for communal action and collective problem solving. Participants also were found to distrust “outsiders” and preferred programs developed by members of their own community. The results of this study show that wildfire mitigation programs based on local culture can be well supported in an Aboriginal community.  相似文献   

19.
北极斯瓦尔巴德(Svalbard)群岛是研究人类活动对全球生态环境影响的重要地区之一,而了解该地生态环境的现状对揭示人类活动影响下全球生态环境的变化具有重要的科学意义。为此,本研究采集了位于Svalbard群岛新奥尔松(Ny-?lesund)的Austre Lovénbreen和Pedersenbreen冰川前沿的表层土壤,对元素Ni、Pb、V、Cu、Zn、Mn、Al和Fe的含量和分布特征进行了研究,并对这些金属元素的来源进行了初步探讨。结果表明, Austre Lovénbreen冰川表层土壤中金属元素平均含量表现为CuPbNiVZnMnAlFe,Pedersenbreen冰川表层土壤中金属元素的平均含量表现为NiPbVCuZnMnAlFe。Austre Lovénbreen和Pedersenbreen冰川前沿表层土壤中金属元素的变异系数值分别位于0.13—0.45和0.12—0.98。Austre Lovénbreen冰川前沿表层土壤中Ni、Pb、V、Mn、Al和Fe等元素的平均含量与Pedersenbreen冰川相近,但Pedersenbreen冰川前沿的表层土壤中Cu和Zn的平均含量要远远高于Austre Lovénbreen冰川。Pedersenbreen冰川前沿表层土壤中Pb的高富集因子点靠近人类活动区域。经主成分分析, Austre Lovénbreen冰川和Pedersenbreen冰川前沿表层土壤中Ni、V、Al和Fe源于母岩风化, Mn除来源于母岩风化外还可能受到了人类活动的影响。Austre Lovénbreen冰川前沿表层土壤中Pb源于母岩风化,但Pedersenbreen冰川前沿表层土壤中Pb除母岩风化源外还可能受到人为活动的影响。Austre Lovénbreen冰川前沿表层土壤中Cu和Zn源于母岩风化,而Pedersenbreen冰川前沿表层土壤中Cu和Zn可能来源于土壤风化和母岩输送过程中的元素分馏。  相似文献   

20.
The Petexbatún region of Guatemala's Petén tropical forest lowlands has been largely deforested since the early 1980s as landless peasants have turned even national parks into milpas. The soils of these tropical forest, karst landscapes are known mainly from small-scale maps and archaeological investigations. This paper investigates soil catenas and natural slope processes from the region's last virgin tropical forests and compares these with catenas and processes on slashed and burned slopes. Soils were sampled and analyzed for physical, fertility, and taxonomic measures. This primary forest toposequence forms a typical downward translocation catena, with the thickest soils (>200 cm) in depressions, the thinnest soils on shoulder slopes, and moderately thin soils on the crests and backslopes. Most crest and sloping soils are Lithic Rendolls and contain simple O-A-C horizon sequences, and most soils have little sign of either eluviation or illuviation. A few deeper soils on the slopes are Vertic Rendolls and have moderate slick-ensides, whereas footslopes and seasonally drained depressions are well developed Vertisols. The primary forest soil catena was compared with two slash-and-burn milpas, one with comparable slopes and one with steeper slopes. The comparably sloped milpa had soil thicknesses that were 7.9 to 13.8 cm thinner, truncated horizons, and physical evidence of erosion. The steeper milpa had soil thicknesses that were 11.1 to 18.2 cm thinner and also had truncated horizons and physical evidence of erosion. Where ancient Maya terraces (Late Classic, ca. 550 to 830 A.D.) are present in the slash-and-burn landscape, an average of 25 to 46.5 cm soil remain upslope and 9.3 to 16.1 cm remain downslope. The findings show high soil truncation rates and erosion to bedrock in a decade in one place, though ancient Maya terraces are still holding 2.7 to 3.6 times more soil than the surrounding hillslopes. Despite high modern erosion, lake sediments show surprisingly low soil losses in the Maya Late Classic during the period of the most intensive land use. In contrast, studies at Copán, Honduras and in the northern Petén, where terrace evidence is scant, show high rates of erosion during this period. [Key words: soil catenas, tropical deforestation, milpa, soil erosion, Maya Lowlands.]  相似文献   

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