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1.
Bojie Fu 《地理学报(英文版)》2020,(4):688-688
We,Faculty of Geographical Science,Beijing Normal University,are pleased to announce the launch of Geography and Sustainability(GeoSus,ISSN2096-7438).GeoSus is an international,peer-reviewed,open access journal.It publishes original and significant,cutting-edge research related to geography and sustainability,encourages wider analysis and innovative thinking about global or regional sustainability through the bridging and synthesis of physical geography,human geography,ecology,hydrology,atmospheric,climate and social sciences. 相似文献
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This paper reviews the past history of comparisons between lacustrine records of chironomid-inferred summer temperatures (CI-T) and peat bog-derived records of surface wetness (BSW), and develops a new summer temperature record for the mid-late Holocene for Northern Britain from Bigland Tarn, Cumbria. The CI-T reconstruction is well dated, and corresponds well with the only two other CI-T records for Britain. Comparisons are made with BSW records from northern Britain, which show consistent similarities over centennial to millennial timescales, demonstrating that at this resolution cooler summers equated with a wetter climate, at least during the mid- to late-Holocene. 相似文献
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Richard Moye 《Urban geography》2013,34(2):236-263
A limited number of studies have addressed residential self-selection when considering the relationship between the built environment (BE) and physical activity. Ignoring self-selection may bias the estimate of the strength of the relationship and misinform public policy. Using 2011 data from the Twin Cities, this study employs cross-sectional and quasi-longitudinal analyses to disentangle the impacts between self-selection (through residential preferences and travel attitudes) and neighborhood characteristics on active travel (AT). The two approaches produce somewhat different outcomes: attitudinal factors are extensively present in the cross-sectional analysis and the associations between neighborhood characteristics and AT are greatly attenuated after controlling for attitudinal factors. In contrast, neighborhood characteristics play a dominant role in the quasi-longitudinal analysis, while attitudinal and demographic characteristics carry additional impacts on AT. Overall, both preferences and attitudes help explain the difference in AT. I find that while physical activity infrastructure impacts biking, physical activity infrastructure together with transit and accessibility affects walking, even after controlling for demographic and attitudinal characteristics. The results highlight the importance of shaping the BE in order to provide an infrastructure of alternative modes of transport and access to different land uses in policy efforts to increase AT. 相似文献
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In the past decade, international development practitioners have increasingly argued that migration improves the food security of households at origin, by providing the capital necessary for agricultural intensification or food purchase. These debates have occurred largely in isolation from a discussion of the values that underpin food production and consumption in the communities that migrants call home. We question the assumption that a shift from an agricultural-based economy to an economy based on remittances increases the ability of communities to secure access to food in the face of rapid economic and cultural change. In this paper, we present two independently conducted studies from Nepal and Vanuatu that investigate the impact of out-migration on local perceptions of agricultural and residential land and the meaning given to food security. Our data reveal that the value changes associated with large-scale out-migration have the potential to make the agricultural sector at origin more vulnerable, unproductive, unsustainable or unattractive, leaving a longer-term impact on food security. We offer some reflections on the implications of these findings for the structure of the migration–food security nexus. 相似文献
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Journal of Geographical Sciences - The world is facing a poverty crisis. Despite the great achievements that have been made in poverty alleviation over the past two decades, the extent of poverty... 相似文献
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Ray McPadden 《社会与自然资源》2014,27(12):1321-1330
Federal land management agencies are increasingly relying on collaborative partnerships for managing national trails, heritage areas, scenic rivers, and recreation areas. For agencies such as the National Park Service, these joint approaches are significantly different from traditional management approaches. This article uses a case study of the Juan Bautista De Anza National Historic Trail to identify partnership lessons for this case and other protected areas that rely on public–private partnerships. The research highlights partnership issues with nonprofit capacity and mission alignment, project momentum, and leadership dilemmas. We suggest that agencies such as the National Park Service need to assess the mission and capacity of community and nonprofit groups to determine their partnership approach. This is a significant shift, from agencies simply needing to find organizations willing to partner on collaborative management efforts, to a role in assessing, forming, and developing nonprofit partners. 相似文献
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Qin Yangmin Zhang Lihua Swindles Graeme T. Yang Huan Gu Yansheng Qi Shihua 《Journal of Paleolimnology》2021,66(1):29-40
Journal of Paleolimnology - We present a?~?40–year record of environmental change in the Swan Oxbow, Yangtze River, China, inferred from testate amoeba and sedimentary pigment... 相似文献
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《The Professional geographer》2013,65(4):453-464
Shear stress is a fundamental parameter in many sediment transport expressions. It is commonly estimated from information contained in the velocity profile, specifically, shear velocity, u ?, and roughness length, z 0 Under ideal conditions, the functional relationship between elevation above the bed and flow velocity is log-linear, as expressed by the “law of the wall.” Unless the field data conform exactly to this ideal relationship, there is uncertainty in estimates of u ? and z 0. derived from velocity profiles. This uncertainty depends on the degree of scatter or deviation from the assumed log-linear model. Expressions are presented to quantify the error and to correct for it. Guidelines are suggested to minimize potential uncertainty, especially with regard to instrument deployment and velocity profile analysis. Calculation of confidence intervals around estimates of u ? and z 0, as proposed by Wilkinson (1984), is necessary and recommended. 相似文献
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Matthias Delafontaine Tijs Neutens Nico Van de Weghe 《International journal of geographical information science》2013,27(6):1131-1154
This article introduces a novel geographical information system toolkit for measuring and mapping the accessibility of individuals to services. The toolkit contributes to earlier implementations by combining aspects of both place-based and person-based accessibility measures. To this end, place-based accessibility measures are derived from a person-based framework by considering space–time prisms that are centred at service facilities rather than individual anchor points. The implementation is also innovative by explicitly accounting for the opening hours of service delivery in its accessibility measurement. In addition, the toolkit is aimed to be user-friendly and to generate insightful and comprehensible results for non-technically oriented users, which is illustrated in a brief case study about library accessibility in Ghent (Belgium). 相似文献
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I.H. Burnley 《The Australian geographer》1998,29(1):49-70
This paper examines the patterns of residential concentration and dispersion and the socio‐economic profiles of major immigrant groups from Asia in Sydney at the 1991 Census, taken soon after the largest immigrant boom in Sydney's urban history, which occurred between 1986 and 1988. It makes use of detailed birthplace, language and religion cross‐tabulations by area and socio‐economic indicators, as well as four‐digit occupational data from the Census. It then tests to what extent immigration flows from different parts of Asia have been linked to Sydney's emergence as a global city, and whether the disadvantage or advantage associated with the settlement of some communities is tied to restructuring, globalisation, language difficulties, residential concentration, or other factors. 相似文献
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Fossil Trichoptera (caddisfly) remains have been identified and quantitatively recorded in the late-glacial and early-Holocene sediments from Kråkenes Lake, western Norway. The sediment sequence was deposited between 12,300 and 8850 14C BP, covering the Allerød, Younger Dryas, and early-Holocene periods. The first Trichoptera were recorded at 12,000 14C BP, and during the Allerod a diverse assemblage of Limnephilidae taxa developed in the lake. By about 11,400 14C BP the relatively thermophilous Polycentropus flavomaculatus and Limnephilus rhombicus were present, suggesting that the summer water temperature was at least 17 °C. This temperature fell by 5-8 °C at the start of the Younger Dryas, and the thermophilous taxa were replaced within 20-40 14C yrs by Apatania spp., including the arctic-alpine A. zonella, suggesting a maximum summer water temperature of 10-12 °C. The Trichoptera assemblage was impoverished in numbers and in diversity over the next 200 yrs as the severe conditions of the Younger Dryas developed. As soon as temperatures rose and glacial meltwater and silt input ended about 700 14C yrs later, the resident Apatania assemblage expanded immediately, within 10 yrs. About 130 yrs later, thermophilous taxa replaced Apatania, and a much more diverse assemblage than in the Allerod occupied the varied habitats made available by the development of the Holocene lake ecosystem. The 130 yr delay may have been caused by a gradual temperature increase crossing a critical threshold, or by the time taken for thermophilous taxa to migrate from their Younger Dryas refugia. 相似文献
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Kerstin Huber Kaarina Weckström Ruth Drescher-Schneider Johann Knoll Jutta Schmidt Roland Schmidt 《Journal of Paleolimnology》2010,43(1):131-147
A sediment core section from Längsee, a small meromictic lake in the southern Alpine lowland (Carinthia, Austria) close to the Würmian ice margin, was investigated by means of diatoms and pollen. The main aims of the study were to reconstruct water temperature as a signal of climate change during the last glacial termination, compare the aquatic and terrestrial response to the changing climate, and place our findings into a climatic frame on the northern hemispheric scale. A calibration data set (ALPS06) of 116 lakes was constructed using data from newly studied lakes and from two previously published data sets and we established a transfer function for predicting summer epilimnetic water temperatures (SEWT). A locally weighted weighted average regression and calibration model (R jack 2 = 0.89; RSMEP = 1.82°C) was applied to the fossil diatom assemblages in order to reconstruct SEWT. Three major sections were distinguished in the time window of approximately 19–13 cal ka BP, which fitted well with the oxygen isotope curve and the isotope-event stratigraphy from the Greenland ice-core GRIP. The first section was a warming period (SEWT range from 11.6 to 18.0°C; average 15.8°C = ca. 6°C below present) called the Längsee oscillation, which probably correlates with the warmer sub-section (GS-2b) of the Greenland Stadial 2. The subsequent section represents a climate cooling, called the Längsee cold period (SEWT range between 10.6 and 15.9°C; average 12.9°C), which probably corresponds with the sub-section GS-2a of the Greenland Stadial 2, the Heinrich 1 cold event of the North Atlantic, and partially the Gschnitz Stadial in the Alps. The Längsee cold period shows a tri-partition: Two colder phases are separated by a warmer inter-phase. The passive ordination of the core sample scores along maximum water depth indicated that the Längsee cold period was drier than the Längsee oscillation. Strong short-term fluctuations during the Längsee oscillation and the Längsee cold period indicate climate instability. The third section represented climate warming during the Längsee late glacial interstadial (=Greenland Interstadial 1, GI-1) with an average SEWT of 17.5°C. From the minor climatic fluctuations during this interstadial, mainly indicated by pollen, the fluctuation most likely related to the Gerzensee oscillation showed a SEWT decline. During the early immigration and expansion period of shrubs and trees, aquatic and terrestrial records showed distinct discrepancies that might have arose because of time lags in response and differences in sensitivity. 相似文献
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This paper questions the main techniques of mapping in the context of aircraft noise in the vicinity of airports, and compares these techniques in terms of their purpose, benefits and limitations. Then the paper describes a method to summarise radar traces of a given air transport departure or arrival route into a median route and its envelope containing 80% of flights. This makes it possible to map global and easy-to-read maps of current air procedures around airports based on actual pathways flown by the aircraft. It also makes it possible to investigate the impact of change in aeronautical procedures on the actual geography of air routes around airports. Such maps complement noise contour maps and offer a good basis for debating aeronautical procedures at airports whose operations expose the population to noise. 相似文献
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《The Professional geographer》2013,65(4):477-490
Abstract This article examines two key aspects of land-cover change in the south of the Chocó region. First, it assesses and compares the local impact on forest condition of labor-intensive and capital-intensive commercial logging. Second, it assesses the regional significance and permanency of these changes. Studies of land-cover change associated with commercial logging have focused almost exclusively on capital-intensive extraction and have assumed that after logging, degraded forests are transformed into agricultural cover. This study shows that both capital- and labor-intensive logging result in similar land-cover changes (i.e., forest degradation) if the timber sought is the same. However, labor-intensive loggers also seek timber species not sought by capital-intensive loggers, and this impact is statistically different from the impact of the extraction of the first group of species. Results also show that only a small fraction (20–30 percent) of the area logged is later converted to agricultural cover types. The persistence of logged forests means that up to 20 percent of the remaining forest cover could correspond to forests with significant and lasting levels of degradation. Furthermore, the different production requirements for each group of species also mean that there is a spatial differentiation in the impact of logging in the region. Logged forests are arranged into two consecutive corridors on each side of access routes (e.g., rivers). The first corridor corresponds to a narrow (approximately 1-km) band of high-intensity degradation. The second, broader (approximately 2-km) forest band, with lower levels of degradation, extends inland along first-tier corridors. A key factor determining the permanency of this land-cover pattern is the strong control local communities have over the land in the region. This limits the spread of patterns observed in other frontier areas, especially the conversion of logged forests into agricultural cover. 相似文献
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Agathe Fourmont Jean-Jacques Macaire Jean-Gabriel Bréhéret 《Journal of Paleolimnology》2009,41(3):471-490
Since the end of the Last Glacial Maximum, hydrology in Europe has been influenced by both climate changes, and since Neolithic
times, an increase in human activity. Paleohydrological reconstructions, especially from lake studies, can help identify the
respective impact of these two factors. The present work focuses on a lacustrine geosystem, the Sarliève paleolake in the
Massif Central (France), in an unusually dry, temperate area. The lake sediment geometry (core drillings, geotechnical methods),
and the geochemical and mineralogical characterization of the catchment rocks and soils, and of the lacustrine deposits, indicate
major variations in paleohydrology during the last 12,000 years as dated by 14C, palynology and tephrochronology. In addition, a model quantifying detrital versus biochemical lacustrine components was
developed to identify hydrological trends. The data show that the Sarliève area was characterized mainly by remarkably dry
conditions, hence sharpening the climatic trends at middle latitudes in Western Europe. Three main hydrological phases are
distinguished since the Late Glacial: (1) 13.7–7.5 ka cal BP, a dominant dry climate, with a peak at ca. 8 ka cal BP, leading
to a lowstand in water level and unusual mineral authigenesis, zeolite then dolomite, constituting up to 60% of the lacustrine
sediments; (2) 7.5 to ca. 5.3 ka cal BP, repeated short-duration hydrological alternations that could have been climate-driven:
lowstands in water level with up to 60% biochemical minerals versus higher water levels with <10% biochemical minerals; (3)
5.3 ka cal BP to the Middle Ages (i.e. beginning in the 5th century AD), a hydrological trend towards perennial high water
level, with mainly detrital sediments, probably linked to climate evolution, except periods of obvious human-driven drying
during the last two millennia. 相似文献
18.
Dennis P. Cox 《Natural Resources Research》1993,2(2):82-91
Quantitative mineral resource assessments used by the United States Geological Survey are based on deposit models. These assessments consist of three parts: (1) selecting appropriate deposit models and delineating on maps areas permissive for each type of deposit; (2) constructing a grade-tonnage model for each deposit model; and (3) estimating the number of undiscovered deposits of each type. In this article, I focus on the estimation of undiscovered deposits using two methods: the deposit density method and the target counting method.In the deposit density method, estimates are made by analogy with well-explored areas that are geologically similar to the study area and that contain a known density of deposits per unit area. The deposit density method is useful for regions where there is little or no data. This method was used to estimate undiscovered low-sulfide gold-quartz vein deposits in Venezuela.Estimates can also be made by counting targets such as mineral occurrences, geophysical or geochemical anomalies, or exploration plays and by assigning to each target a probability that it represents an undiscovered deposit that is a member of the grade-tonnage distribution. This method is useful in areas where detailed geological, geophysical, geochemical, and mineral occurrence data exist. Using this method, porphyry copper-gold deposits were estimated in Puerto Rico. 相似文献
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ZHAO Xiaoyuan ZHANG Zhongwei LIU Xiaojie ZHANG Qian WANG Lingqing CHEN Hao XIONG Guangcheng LIU Yuru TANG Qiang RUAN Huada Daniel 《地理学报(英文版)》2023,(10):2094-2116
There is a great uncertainty in generation and formation of non-point source(NPS)pollutants, which leads to difficulties in the investigation of monitoring and control. However,accurate calculation of these pollutant loads is closely correlated to control NPS pollutants in agriculture. In addition, the relationships between pollutant load and human activity and physiographic factor remain elusive. In this study, a modified model with the whole process of agricultural NPS pollutant migration was ... 相似文献