River flood seasonality in the Northeast United States: Characterization and trends     

Mathias J. Collins 《水文研究》2019,33(5):687-698

The New England and Mid‐Atlantic regions of the Northeast United States have experienced climate‐induced increases in both the magnitude and frequency of floods. However, a detailed understanding of flood seasonality across these regions, and how flood seasonality may have changed over the instrumental record, has not been established. The annual timing of river floods reflects the flood‐generating mechanisms operating in a basin, and many aquatic and riparian organisms are adapted to flood seasonality, as are human uses of river channels and flood plains. Changes in flood seasonality may indicate changes in flood‐generating mechanisms, and their interactions, with important implications for habitats, flood plain infrastructure, and human communities. I applied a probabilistic method for identifying flood seasons at a monthly resolution for 90 Northeast U.S. watersheds with natural, or near‐natural, flood‐generating conditions. Historical trends in flood seasonality were also investigated. Analyses were based on peaks‐over‐threshold flood records that have, on average, 85 years of data and three peaks per year—thus providing more information about flood seasonality than annual maximums. The results show rich detail about annual flood timing across the region with each site having a unique pattern of monthly flood occurrence. However, a much smaller number of dominant seasonal patterns emerged when contiguous flood‐rich months were classified into commonly recognized seasons (e.g., Mar–May, spring). The dominant seasonal patterns identified by manual classification were corroborated by unsupervised classification methods (i.e., cluster analyses). Trend analyses indicated that the annual timing of flood‐rich seasons has generally not shifted over the period of record, but 65 sites with data from 1941 to 2013 revealed increased numbers of June–October floods—a trend driving previously documented increases in Northeast U.S. flood counts per year. These months have been historically flood‐poor at the sites examined, so warm‐season flood potential has increased with possible implications for aquatic and riparian organisms.  相似文献   

Depiction of Wild Food Foraging Practices in the Media: Impact of the Great Recession     

Sonya Sachdeva  Marla R. Emery  Patrick T. Hurley 《社会与自然资源》2018,31(8):977-993

The practice of gathering and harvesting wild foods has seen renewed interest in recent decades. In addition to contributing to food security and food sovereignty, foraging plays a role in promoting socioecological resilience and creating communities of belonging. However, foraging is generally prohibited by regulations governing public lands in the United States and elsewhere. The growth in food forests suggests public policymakers and land managers’ may be interested in reconsidering this broad prohibition of foraging but require an information base to do so. While a body of research on foraging exists, news media coverage of foraging represents an additional, readily available source of input. As a consequence, framings of foraging in media coverage likely influence managers’ deliberations on this practice. The current paper uses automated content analysis to understand how the practice of gathering and consuming wild foods is framed in print and digital news media, and how these depictions have varied in a 15-year period that includes the Great Recession. Our results show that prevalent framings of foraging represent it variously as a self-provisioning practice or a source of luxury commodities and experiences, with economic uncertainty appearing to affect the frequency of each framing by news media sources. Given managers’ ease of access to them, these distinct framings may influence future regulatory landscapes of foraging.  相似文献   

Global impact of a climate treaty if the Human Development Index replaces GDP as a welfare proxy     

Jeroen C. J. M. van den Bergh 《Climate Policy》2018,18(1):76-85

This study explores the implications of shifting the narrative of climate policy evaluation from one of costs/benefits or economic growth to a message of improving social welfare. Focusing on the costs of mitigation and the associated impacts on gross domestic product (GDP) may translate into a widespread concern that a climate agreement will be very costly. This article considers the well-known Human Development Index (HDI) as an alternative criterion for judging the welfare effects of climate policy. We estimate what the maximum possible annual average increase in HDI welfare per tons of CO₂ would be within the carbon budget associated with limiting warming to 2°C over the period 2015–2050. Emission pathways are determined by a policy that allows the HDI of poor countries and their emissions to increase under a business-as-usual development path, while countries with a high HDI value (>0.8) have to restrain their emissions to ensure that the global temperature rise does not exceed 2°C. For comparison, the well-known multi-regional RICE model is used to assess GDP growth under the same climate change policy goals.

Policy relevance

This is the first study that shifts the narrative of climate policy evaluation from one of GDP growth to a message of improving social welfare, as captured by the HDI. This could make it easier for political leaders and climate negotiators to publicly commit themselves to ambitious carbon emission reduction goals, such as limiting global warming to 2°C, as in the (non-binding) agreement made at COP 21 in Paris in 2015. We find that if impacts are framed in terms of growth in HDI per t CO₂ emission per capita instead of in GDP, the HDI of poor countries and their emissions are allowed to increase under a business-as-usual development path, whereas countries with a high HDI (>0.8) must control emissions so that global temperature rise remains within 2°C. Importantly, a climate agreement is more attractive for rich countries under the HDI than the GDP frame. This is good news, as these countries have to make the major contribution to emissions reductions.  相似文献   

GIS diffusion in Uganda     

Sami Eria  Robert B. McMaster 《International journal of geographical information science》2017,31(5):884-906

Despite myriad studies having been carried out on the diffusion of geographical information systems (GIS) technology, only a limited number have been done within the context of developing countries. This paper addresses the research question, how did the diffusion of GIS technology occur in Uganda? Mixed methods were used for data collection, and analysis was performed using a theoretical framework called the diffusion of innovations (DOI). The results of the study showed that the adoption of GIS by institutions in Uganda occurred in a classic diffusion pattern consistent with diffusion theory. Adoption of GIS was promoted by its relative advantage over, and compatibility with, existing technologies. It was characterized by both heterophilous and homophilous communication channels, and influenced by change agents and champions. Its rate of adoption followed an S-shaped diffusion curve, and was hampered by bureaucracy, and patronage-based societal norms. This study makes a contribution to literature on GIS diffusion in developing countries.  相似文献   

关于地理空间元数据技术发展趋势的理论探讨   总被引：2，自引：2，他引：0  

周新忠  余木良  陶亮  郭朋飞 《测绘科学》2007,32(2):172-175

随着“数字地球”、“数字中国”等的实施,地理空间元数据作为促进海量空间信息管理和共享的有力工具,其应用有了较快的发展。本文在分析我国地理空间元数据应用现状的基础上,结合地理空间元数据的应用特点,分析了地理空间元数据的标准化、互操作、自动生成等趋势是地理空间元数据发展的必然,并论述了与这些发展趋势相关的实施方法和技术,以及这些趋势之间的辩证关系。  相似文献   

城市化对地下水流系统的影响   总被引：4，自引：0，他引：4  

于开宁  MorrisBL 《华北地质矿产杂志》1999,(2)

随着世界经济的飞速发展和人口增长,城市的规模和数量也在急剧增加,城市化的趋势变得日益明显,尤其在发展中国家。在这一过程中,地下水所扮演的角色越来越重要,揭示城市化与地下水各方面之间的相互影响规律以实现其可持续发展,成为一个全球性的重要研究课题。本文在分析世界城市人口增长规律和地下水对城市供水的重要性基础上;以三个典型示范城市为例,进一步具体探讨了城市化对地下水补给与地下水流系统的影响。最后认为,城市化会引起地下水补给量的增加;但城市大规模和经常性毫无节制地开采地下水可产生明显的地下水位下降、地面沉降和盐水入侵而导致地下水流系统的剧烈改变。  相似文献   

Comparison of trends in stream water quality     

J. M. Potts  D. Hirst  J. D. Miller  A. C. Edwards  D. A. Elston 《水文研究》2003,17(12):2449-2462

A method is described for assessing the strength of evidence for differences in the trends in chemical concentrations in stream water between catchments. A smoothing spline technique is used to model changes in water quality as a result of changes in flow rates, seasonal effects and an underlying trend. The method involves fitting the model twice, once with the underlying trends constrained to be identical for each river and once with the trends unconstrained. Statistical properties are assessed by simulation methods that allow for the autocorrelation in the residuals from the unconstrained fit. The method is applied to data from two streams in the Balquhidder catchments in the Highlands of Scotland and to data from the Dee, Don and Ythan rivers in the north‐east of Scotland. Copyright © 2003 John Wiley & Sons, Ltd.  相似文献   

Evaluation of recent hydro-climatic changes in four tributaries of the Niger River Basin (West Africa)     

Djigbo Félicien Badou  Evison Kapangaziwiri  Bernd Diekkrüger  Jean Hounkpè  Abel Afouda 《水文科学杂志》2017,62(5):715-728

West Africa experienced severe drought during the 1970s and 1980s, posing a threat to water resources. A wetter climate more recently suggests recovery from the drought. The Mann-Kendall trend and Theil-Sen’s slope estimator were applied to detect probable trends in weather elements in four sub-basins of the Niger River Basin between 1970 and 2010. The cross-entropy method was used to detect breakpoints in rainfall and runoff, Spearman’s rank test for correlation between the two, and cross-correlation analysis for possible lags. Results showed an overall increase in rainfall and runoff and a decrease in sunshine duration. Spearman’s coefficients suggest significant (5%) moderate to strong rainfall–runoff correlation for three sub-basins. A significant lower runoff was observed around 1979, with a rainfall break around 1992, indicating possible cessation of the drought. Temperatures increased significantly, at 0.02–0.05°C year^-1, with a negative wind speed trend for most stations. Half of the stations exhibited an increase in potential evapotranspiration.