bluuebunny/crossref_metadata_2025_split huggingface dataset:
Arctic sea ice decline and continental cold anomalies: Upstream and downstream effects of Greenland blocking
Authors: Chen Xiaodan , Luo Dehai 
Published: March 2017

AbstractThe influence of Greenland blocking on continental cold anomalies in the Northern Hemisphere is examined. It is found that westward moving Greenland blocking (WGB) events in the recent decade are more strongly related to the sea ice decline over the Baffin Bay, Davis Strait, and Labrador Sea (BDL), while the quasi‐stationary Greenland blocking (QGB) events are more strongly related to the negative phase of the North Atlantic Oscillation. The frequency of WGB events is significantly increased owing to reduced mid‐high‐latitude westerly winds in the North Atlantic and its upstream region because of intensified Arctic warming related to the large BDL sea ice decline. It is further revealed that North American low temperatures are more sensitive to the WGB, while European low temperatures are more sensitive to the QGB. For the WGB, an intense cold anomaly is seen over the eastern North America. But for the QGB, strong cold anomalies appear over the North Europe and eastern Asia. Thus, it is concluded that more winter cold air outbreaks should occur over the eastern North America, if large BDL sea ice decline continues in the recent decade.
Radar observations of density gradients, electric fields, and plasma irregularities near polar cap patches in the context of the gradient‐drift instability
Authors: Lamarche Leslie J. , Makarevich Roman A. 
Published: March 2017

AbstractWe present observations of plasma density gradients, electric fields, and small‐scale plasma irregularities near a polar cap patch made by the Super Dual Auroral Radar Network radar at Rankin Inlet (RKN) and the northern face of Resolute Bay Incoherent Scatter Radar (RISR‐N). RKN echo power and occurrence are analyzed in the context of gradient‐drift instability (GDI) theory, with a particular focus on the previously uninvestigated 2‐D dependencies on wave propagation, electric field, and gradient vectors, with the latter two quantities evaluated directly from RISR‐N measurements. It is shown that higher gradient and electric field components along the wave vector generally lead to the higher observed echo occurrence, which is consistent with the expected higher GDI growth rate, but the relationship with echo power is far less straightforward. The RKN echo power increases monotonically as the predicted linear growth rate approaches zero from negative values but does not continue this trend into positive growth rate values, in contrast with GDI predictions. The observed greater consistency of echo occurrence with GDI predictions suggests that GDI operating in the linear regime can control basic plasma structuring, but measured echo strength may be affected by other processes and factors, such as multistep or nonlinear processes or a shear‐driven instability.
On extracting sediment transport information from measurements of luminescence in river sediment
Authors: Gray Harrison J. , Tucker Gregory E. , Mahan Shannon A. , McGuire Chris , Rhodes Edward J. 
Published: March 2017

AbstractAccurately quantifying sediment transport rates in rivers remains an important goal for geomorphologists, hydraulic engineers, and environmental scientists. However, current techniques for measuring long‐time scale (102–106 years) transport rates are laborious, and formulae to predict transport are notoriously inaccurate. Here we attempt to estimate sediment transport rates by using luminescence, a property of common sedimentary minerals that is used by the geoscience community for geochronology. This method is advantageous because of the ease of measurement on ubiquitous quartz and feldspar sand. We develop a model from first principles by using conservation of energy and sediment mass to explain the downstream pattern of luminescence in river channel sediment. We show that the model can accurately reproduce the luminescence observed in previously published field measurements from two rivers with very different sediment transport styles. The model demonstrates that the downstream pattern of river sand luminescence should show exponential‐like decay in the headwaters which asymptotes to a constant value with further downstream distance. The parameters from the model can then be used to estimate the time‐averaged virtual velocity, characteristic transport lengthscale, storage time scale, and floodplain exchange rate of fine sand‐sized sediment in a fluvial system. The sediment transport values predicted from the luminescence method show a broader range than those reported in the literature, but the results are nonetheless encouraging and suggest that luminescence demonstrates potential as a sediment transport indicator. However, caution is warranted when applying the model as the complex nature of sediment transport can sometimes invalidate underlying simplifications.
Hydrodynamics of steep streams with planar coarse‐grained beds: Turbulence, flow resistance, and implications for sediment transport
Authors: Lamb Michael P. , Brun Fanny , Fuller Brian M. 
Published: March 2017

AbstractThe hydraulics of steep mountain streams differ from lower gradient rivers due to shallow and rough flows, energetic subsurface flow, and macro‐scale form drag from immobile boulders and channel and bed forms. Heightened flow resistance and reduced sediment transport rates in steep streams are commonly attributed to macro‐scale form drag; however, little work has explored steep river hydrodynamics in the absence of complex bed geometries. Here we present theory for the vertical structure of flow velocity in steep streams with planar, rough beds that couples surface and subsurface flow. We test it against flume experiments using a bed of fixed cobbles over a wide range of bed slopes (0.4–30%). Experimental flows have a nearly logarithmic velocity profile far above the bed; flow velocity decreases less than logarithmically toward the bed and is nonzero at the bed surface. Velocity profiles match theory derived using a hybrid eddy viscosity model, in which the mixing length is a function of height above the bed and bed roughness. Subsurface flow velocities are large (>1 m/s) and follow a modified Darcy‐Brinkman‐Forchheimer relation that accounts for channel slope and shear from overlying surface flow. Near‐bed turbulent fluctuations decrease for shallow, rough flows and scale with the depth‐averaged flow velocity rather than bed shear velocity. Flow resistance for rough, planar beds closely matches observations in natural steep streams despite the lack of bed forms or channel forms in the experiments, suggesting that macro‐scale form drag is smaller than commonly assumed in stress‐partitioning models for sediment transport.
Coastal Erosion Processes and Landforms
Authors: Trenhaile Alan S. 
Published: March 2017

Abstract
Most landforms on rocky coasts are the result of erosion, although these coasts often host a variety of sandy to boulder beaches, as well as functioning as an important source of sediment for adjacent coastal areas. The erosional processes and mechanisms, including mechanical wave erosion, weathering, bioerosion, and various types of mass movement, produce landforms such as bays and headlands, sea cliffs, shore platforms, and arches, stacks, and caves. Many types of rock coast develop very slowly and may have been inherited, in part, from previous interglacial stages when sea level was similar to today.
Cryosphere Studies: History
Authors: Barry Roger G. 
Published: March 2017

Abstract
Scientific study of most components of the cryosphere (all forms of terrestrial snow and ice) began around 1900. The term “cryosphere” was introduced in 1923 by A.B. Dobrowolski, in Poland, but came into wide use only in the 1990s. The advent of remote sensing in the 1970s has played a major role in global mapping and in monitoring components of the cryosphere.
Business Improvement Districts
Authors: Ward Kevin 
Published: March 2017

Abstract
Business improvement districts (BIDs) are public–private partnerships in which property and business owners in a defined geographic area elect to make a collective contribution to the maintenance, development, and marketing/promotion of their commercial district. The BID program first emerged in Toronto in the early 1970s, spread to the United States over the course of the decade, and was introduced into the United Kingdom in 2001. Subsequently it has appeared in a host of other countries, including Australia, Germany, Japan, and South Africa. The program centers on a small number of activities, primarily those aiming to improve the physical, promotional, and surveillance infrastructure around commercial areas.
Cultural Studies
Authors: Cupples Julie , Glynn Kevin 
Published: March 2017

AbstractCultural studies is an overtly politicized, interdisciplinary field that studies relationships between cultural practices and systems of power. From its earliest days it has mounted a radical critique of traditional notions and practices of academic disciplinarity. It first emerged in Britain around the work done at the University of Birmingham's Centre for Contemporary Cultural Studies, which was established in 1964 and produced a highly influential body of scholarship that initially cohered loosely around Marxist, structuralist, semiotic, and ethnographic modes of analysis. Over the years cultural studies has substantially expanded, both theoretically and geographically, eventually becoming a kind of global intellectual movement. Since the 1980s, the field has internationalized rapidly and given rise to numerous regional varieties in Africa, Asia, Australia, Latin America, and the United States. The intellectual debates generated through and around cultural studies have had a profound effect on disciplines across the humanities and social sciences, including geography.
Cores and Peripheries
Authors: Lima Marcos Costa 
Published: March 2017

AbstractThe intertwined concepts of center and periphery, denoting the relative positions of given entities in space, are widely used not only in the social sciences, but also in urban design, physics, and the history of science. In the context of the social sciences, the core refers to regions that have consolidated their hegemony in terms of leadership in science and technology and economic power, that is, the highly industrialized countries in Europe and North America and some Asian countries. After the big changes taking place in emerging countries, a question arises: to what extent are the realities subsumed within current dynamics of North–South or center–periphery relations likely to change, along with their interpretation?
Climate Adaptation/Mitigation
Authors: McBean Gordon A. 
Published: March 2017

Abstract
The climate is changing due to humans' actions, and humans need to respond through mitigation – emission reductions – to reduce the rate of change and through adaptation to reduce the impacts and gain the benefits. The Climate Convention provides an international framework for both mitigation and adaptation but countries need to develop and implement national strategies on the basis of scientific‐technological and socioeconomic information and analyses, and their national to local capabilities.
Corporations and the Law
Authors: Barkan Joshua E. 
Published: March 2017

Abstract
Geographic research on corporations has examined the ways companies organize the production and distribution of goods across capitalist economies. Legal rulings and regulations are integral to this process, yet the geographic study of corporations and the law remains in its infancy. This entry covers the history of corporations and the law, with particular attention to the role of geography in legal definitions of the corporation. It concludes with contemporary geographic issues involving law and corporations, particularly under corporate‐led economic globalization, and indicates areas for future research on non‐Western legal systems and the role of legal politics in shaping corporate economies.
Comparative Advantage
Authors: Yeung Godfrey 
Published: March 2017

Abstract
Comparative advantage is the capacity of an agent, a region, or a country to produce a specific commodity or provide a service at a lower opportunity cost over another agent, region, or country. It is one of the fundamental concepts in international economics and is normally used to support free trade and pertinent policy agendas in the Washington Consensus. Heterodox economists and neo‐Marxist social scientists, however, argue that empirical evidence illustrates the restrictive assumptions of such free‐trade theories, and neo‐Marxists geographers have typically highlighted the fictitious nature of capital in the debates.
Biosecurity
Authors: Hinchliffe Steve 
Published: March 2017

Abstract

Biosecurity, or making life safe, can be understood by attending to four of its constitutive elements: security, liberalism, a pathogen‐based and an anticipatory approach to danger. These elements, and the spatial tensions that they give rise to, make biosecurity a difficult and sometimes contested exercise in both the control
and
the nurturing of life processes.
Buffers
Authors: Weber Joe 
Published: March 2017

Abstract
Buffers refer to spaces between objects or areas or within a specified distance of an object or place. They appear in a variety of contexts, including vector applications in geographic information systems (GIS), in which they are used to demarcate spaces within particular distances of features, and in political geography, urban planning, and conservation to separate incompatible areas. The meaning and use of the concept can vary significantly among these applications.
Base Flow
Authors: Howard Douglas A. 
Published: March 2017

Abstract
The primary single component of the hydrological cycle that contributes water to sustainable stream flow is groundwater through base flow. Base flow is the groundwater contribution to stream flow. Base flow hydraulically connects the saturated zone to the stream channel, where groundwater intercepts the stream and contributes approximately 40% to its total annual discharge. Base flow's significant contribution to stream flow is evidenced in perennial and intermittent streams over long periods between storm events. Given minor contributions from the vadose zone and free‐fall precipitation on the stream hydrograph, volumetric and geochemical approaches to quantify base flow and runoff contributions have been developed.
Autobiography
Authors: Butz David 
Published: March 2017

Abstract
Autobiography is an epistemological orientation to the production and reception of communicative acts, in which knowledge claims are based on close correspondence between agents and objects of signification. Autobiography has a long history in geography, beginning with empiricist and humanist traditions, and taking new forms in response to feminist, poststructural, post‐phenomenological, and nonrepresentational theoretical and methodological innovations. Autobiographical communication is valued for its ability to convey everyday subjective experience, articulate emotion and affect, facilitate critical reflexivity, nurture relations of solidarity, and express the perspectives of groups whose voices are seldom heard. As a source of insight, autobiography shares many characteristics with other forms of qualitative methodology and qualitative data, including interviews, oral testimony, life history, ethnography, and autoethnography.
Agricultural Environments
Authors: Blumler Mark 
Published: March 2017

Abstract
Agriculture arguably has been the major cause of ecological and evolutionary change on the Earth during the 10 000 years since its inception. Much of the Earth's terrestrial surface is agricultural today. Although originally based on renewable resources, most agriculture today is utterly and unsustainably dependent upon fossil fuels. The degree to which soil erosion and land degradation have resulted is debated, while negative impacts on biodiversity seem to be proceeding rapidly.
Alternative Food Movement
Authors: Galt Ryan E. 
Published: March 2017

AbstractThere are arguably several alternative food movements (AFMs) rather than a singular one. Most exist to challenge the negative consequences of the industrial food system. Geographers and allied scholars have been central to a number of scholarly debates about AFMs centered on neoliberalism, accessibility, and the wellbeing of farmers and farmworkers within them. Organic, fair trade, civic agriculture and sustainable community food systems, food justice, and food sovereignty all form important parts of current AFMs. Each has its own history and dynamics, and one major challenge for AFMs is to find and cultivate unity in diversity.
Brands and Branding
Authors: Pike Andy 
Published: March 2017

AbstractThis entry defines what is meant by brands and branding, explains how they are geographical, introduces the idea of geographical associations, and emphasizes the roles of actors – producers, circulators, consumers, and regulators – in spatial circuits of meaning and value. Origination explains the geographical associations constructed by actors related in spatial circuits in their attempts to cohere and stabilize meaning and value in goods and services brands and their branding in particular spatial and temporal market contexts.
Aid
Authors: Essex Jamey 
Published: March 2017

Abstract
Aid is the transfer of goods, services, and other resources on concessionary and often conditional terms, typically as a form of development or humanitarian assistance. Aid functions through complex networks of official state, intergovernmental, and multilateral institutions, mostly but not entirely in the Global North, working alongside a wide array of private, nongovernmental, and philanthropic organizations and actors. Historically, aid has been closely associated with state strategies of national security and has been an important instrument of statecraft and foreign policy. The Cold War's end and the widespread adoption of neoliberalism have significantly altered the global aid system. Contemporary geographies of aid are shaped by increased South–South connections and flows, the growing role of nonstate actors in aid provision and governance, and the inclusion of social and environmental objectives in aid programs. Critics still contend that aid remains heavily politicized, largely ineffective, and centered on donors rather than recipients.
Branch Plant Economy
Authors: Phelps Nicholas A. 
Published: March 2017

Abstract
The branch plant economy is a concept that emerged in a particular time and from particular places to capture the local development implications of the evolving division of labor within large, often multinational enterprises. Arguably it retains a relevance to understanding some of the present limits to economic development as a result of the integration of local economies into evolving divisions of labor within and between such enterprises. It remains a concept around which important research agendas can be centered, although it may benefit from an injection of new insights from literature elsewhere in economic geography, international business, and development studies.
Biogeography
Authors: Lorimer Jamie , Hodgetts Timothy 
Published: March 2017

Abstract
The subdiscipline of biogeography concerns the diversity and distribution of living organisms, investigating where these are found and the possible reasons why. Whereas traditional biogeography focuses almost solely on environmental and ecological factors, a variety of alternative approaches exist which explore geographies of the “bio” in wider terms. Rejecting distinctions between human and nonhuman life, and between natural and cultural spaces, these alternatives provide a wealth of conceptual resources for developing a more socio‐natural biogeography. This entry highlights a number of such possibilities, which emphasize posthumanist understandings of “nature,” the implications of proliferating knowledge controversies, and the various forms of politics and economics implicated in the spacing and placing of nonhuman life.
Agriculture
Authors: Robinson Guy M. 
Published: March 2017

Abstract
Land used for growing crops occupies around 11% of the world's land surface, with approximately half of the remaining area used as pasture or extensive grazing for animals. The various systems of agricultural production have profound environmental demands, creating agroecosystems in which human activity modifies soil fertility, vegetation, flora, and microclimate. These dynamic systems utilize natural resource inputs, principally climate, water supply, and soils. Microclimate modification and irrigation are prime examples of ways in which farmers modify the environment to produce conditions favorable to the growth of agricultural crops. “Agricultural” soils have been created, which act as reservoirs of water, minerals, and nutrients needed for plant growth. Concerns over the future viability of agriculture acknowledge that many aspects of human‐induced climate change may be antithetical to maintaining current patterns of production. However, agriculture itself contributes to climate change via its role in greenhouse gas emissions. Future demands to increase output to feed a rising population may involve further intensifications to production systems, using advances in biotechnology and thereby further modifying agroecosystems.
Bioprospecting and Biopiracy
Authors: Neimark Benjamin D. 
Published: March 2017

Abstract
Since its introduction at the 1992 Earth Summit in Rio, bioprospecting (drug discovery from nature) has been heralded by the conservation community as a model for achieving sustainable development in areas of high biodiversity. Yet, bioprospecting was continually confronted by critics who deemed it nothing less than biopiracy, or the misappropriation of traditional knowledge and nature. This critique eventually transformed the practice in many ways, including how scientists were able to access and share benefits from commercialization. Even today, as bioprospectors try to reinvent themselves through new technologies and scientific approaches, resistance to the commercialization of nature and knowledge remains deeply entrenched.
Biodiversity
Authors: Gillespie Thomas W. 
Published: March 2017

Abstract
Biodiversity can be defined as the variation of life forms (genetic, species, taxa) within a given ecosystem or region, or across the entire Earth. Measurements of biodiversity have been undertaken by humans for thousands of years. Recently, there has been a rapid evolution of genetic techniques and geographical information systems databases that have changed the way biodiversity is studied. Latitudinal gradients of species are well established, with an increase in diversity from the poles toward the equator. Gradients of temperature and precipitation, along with area, environmental stability, and geographic uniqueness explain a majority of these latitudinal patterns for most taxa. Global datasets of species and taxonomic groups in terrestrial and marine environments have provided great insight into the distribution and diversity of species. Gradients of biodiversity have been shaped by millions of years of evolution and environmental changes, and increases in human populations have significantly changed levels and patterns of biodiversity. A number of techniques have been designed to protect biodiversity, such as identifying endangered species, developing international conventions and national laws, and designating protected areas. There are also a number of methods employed by scientists and geographers to analyze and preserve biodiversity into the next century.