30 years of IJGIS: the changing landscape of geographical information science and the road ahead     

May Yuan 《International journal of geographical information science》2017,31(3):425-434

The International Journal of Geographic Information Science (IJGIS), established in 1987, is the first academic journal devoted solely to Geographical Information Science (GIS) research. This editorial highlights milestones of the journal development and its influences on the field. IJGIS research articles and special issues have been effective in publishing the state of the art and emerging research accomplishments. In light of the changing landscape of GIS, IJGIS welcome papers on meta-analysis studies, literature reviews, and research foresight. This editorial outlines the underlying thinking and expectations for these papers in future volumes. IJGIS aspires to publish research of high novelty and broad interest that pushes the boundary of fundamental and applied GIS. As an independent, multidisciplinary journal driven by the community of authors, reviewers, and readers, community support is key to realizing the aspiration of a major influence on GIS research.  相似文献   

LAND AND SOCIETY IN NEW ZEALAND. Edited by R. F. Watters     

P. R. May 《New Zealand geographer》1966,22(1):99-100

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Assessing the strength of regional changes in near-surface climate associated with a global warming of 2°C   总被引：2，自引：1，他引：1  

Wilhelm May 《Climatic change》2012,110(3-4):619-644

In this study, the strength of the regional changes in near-surface climate associated with a global warming of 2°C with respect to pre-industrial times is assessed, distinguishing between 26 different regions. Also, the strength of these regional climate changes is compared to the strength of the respective changes associated with a markedly stronger global warming of 4.5°C. The magnitude of the regional changes in climate is estimated by means of a normalized regional climate change index, which considers changes in the mean as well as changes in the interannual variability of both near-surface temperature and precipitation. The study is based on two sets of four ensemble simulations with the ECHAM5/MPI-OM coupled climate model, each starting from different initial conditions. In one set of simulations (1860–2200), the greenhouse gas concentrations and sulphate aerosol load have been prescribed according to observations until 2000 and according to the SRES A1B scenario after 2000. In the other set of simulations (2020–2200), the greenhouse gas concentrations and sulphate aerosol load have been prescribed in such a way that the simulated global warming does not exceed 2°C with respect to pre-industrial times. The study reveals the strongest changes in near-surface climate in the same regions for both scenarios, i.e., the Sahara, Northern Australia, Southern Australia and Amazonia. The regions with the weakest changes in near-surface climate, on the other hand, vary somewhat between the two scenarios except for Western North America and Southern South America, where both scenarios show rather weak changes. The comparison between the magnitude of the regional changes in near-surface climate for the two scenarios reveals relatively strong changes in the 2°C-stabilization scenario at high northern latitudes, i.e., Northeastern Europe, Alaska and Greenland, and in Amazonia. Relatively weak regional climate changes in this scenario, on the other hand, are found for Eastern Asia, Central America, Central South America and Southern South America. The ratios between the regional changes in the near-surface climate for the two scenarios vary considerably between different regions. This illustrates a limitation of obtaining regional changes in near-surface climate associated with a particular scenario by means of scaling the regional changes obtained from a widely used “standard” scenario with the ratio of the changes in the global mean temperature projected by these two scenarios.  相似文献   

Estimating greenhouse gas emissions from cattle raising in Brazil     

Mercedes M. C. Bustamante  Carlos A. Nobre  Roberto Smeraldi  Ana P. D. Aguiar  Luis G. Barioni  Laerte G. Ferreira  Karla Longo  Peter May  Alexandre S. Pinto  Jean P. H. B. Ometto 《Climatic change》2012,115(3-4):559-577

The study estimated, for the first time, the greenhouse gas emissions associated with cattle raising in Brazil, focusing on the period from 2003 to 2008 and the three principal sources: 1) portion of deforestation resulting in pasture establishment and subsequent burning of felled vegetation; 2) pasture burning; and 3) bovine enteric fermentation. Deforestation for pasture establishment was only considered for the Amazon and Cerrado. Emissions from pasture burning and enteric fermentation were accounted for the entire country. The consolidated emissions estimate lies between approximately 813 Mt CO₂eq in 2008 (smallest value) and approximately 1,090 Mt CO₂eq in 2003 (greatest value). The total emissions associated with Amazon cattle ranching ranged from 499 to 775 Mt CO₂eq, that of the Cerrado from 229 to 231 Mt CO₂eq, and that of the rest of the country between 84 and 87 Mt CO₂eq. The full set of emissions originating from cattle raising is responsible for approximately half of all Brazilian emissions (estimated to be approximately 1,055 Mt CO₂eq in 2005), even without considering cattle related sources not explicitly estimated in this study, such as energy use for transport and refrigeration along the beef and derivatives supply chain. The potential for reduction of greenhouse gas emissions offered by the Brazilian cattle industry is very high and might constitute Brazil’s most important opportunity for emissions mitigation. The study offers a series of policy recommendations for mitigation that can be implemented by public and private administrators at a low cost relative to other greenhouse gas reduction options.  相似文献   

Liquefaction susceptibility mapping using geotechnical laboratory tests     

M. El May  J. Kacem  M. Dlala 《International Journal of Environmental Science and Technology》2009,6(2):299-308

The soil liquefaction potential has been evaluated for the Ariana Region because of its important socio-economic interest and its location. Liquefaction susceptibility mapping is carried out using a decisional flow chart for evaluation of earthquake-induced effects, based on available data such as paleoliquefaction, geological, groundwater depth, seismotectonic, sedimentary features and geotechnical parameters in particular laboratory testing like grain size analyses and state parameters. Survey results showed that some of these localities are considered as possible sites to soil liquefaction. Indeed, Quaternary alluvium deposits, paleo beaches and recent deposits that edge the lake and the sebka constitute the most susceptible locations to liquefaction. In the east and the west sides of the studied zone, Quaternary deposits are less susceptible to the liquefaction due to the groundwater level deepening and to the relatively old age of the deposits. Elsewhere sedimentary formations are classified as non-liquefiable as they are heavily compacted and old.  相似文献   

Potential future changes in the characteristics of daily precipitation in Europe simulated by the HIRHAM regional climate model   总被引：1，自引：1，他引：0  

Wilhelm May 《Climate Dynamics》2008,30(6):581-603

In this study the potential future changes in various aspects of daily precipitation events over Europe as a consequence of the anticipated future increase in the atmospheric greenhouse gas concentrations are investigated. This is done by comparing two 3-member ensembles of simulations with the HIRHAM regional climate model for the period 1961–1990 and 2071–2100, respectively. Daily precipitation events are characterized by their frequency and intensity, and heavy precipitation events are described via 30-year return levels of daily precipitation. Further, extended periods with and without rainfall (wet and dry spells) are studied, considering their frequency and length as well as the average and extreme amounts of precipitation accumulated during wet spells, the latter again described via 30-year return levels. The simulations show marked changes in the characteristics of daily precipitation in Europe due to the anticipated greenhouse warming. In winter, for instance, the frequency of wet days is enhanced over most of the European continent except for the region on the Norwegian west coast and the Mediterranean region. The changes in the intensity and the 30-year return level of daily precipitation are characterized by a similar pattern except for central Europe with a tendency of decreased 30-year return levels and increased precipitation intensity. In summer, on the other hand, the frequency of wet days is decreased over most of Europe except for northern Scandinavia and the Baltic Sea region. In contrast, the precipitation intensity and the 30-year return level of daily precipitation are increased over entire Scandinavia, central and eastern Europe. The changes in the 30-year return level of daily precipitation are generally stronger than the corresponding changes in the precipitation intensity but can have opposite signs in some regions. Also the distribution of wet days is changed in the future. During summer, for instance, both the frequency and the length of dry spells are substantially increased over most of the European continent except for the Iberian Peninsula. The frequency and the length of wet spells, on the other hand, are generally reduced during summer and increased during winter, again, with the exception of the Iberian Peninsula. The future changes in the frequency of wet days in winter are related to a change in the large-scale flow over the North Atlantic and a corresponding shift of the North Atlantic storm track. The reduction in the frequency of wet days in summer is related to a northward extension of the dry subtropical region in the future, with a reduction of the convective activity because of the large-scale sinking motion in the downward branch of the Hadley cell. Because the atmosphere contains more moisture in the warmer future climate, the amount of precipitation associated with individual low-pressure systems or with individual convective events is increased, leading to a general increase in the intensity of individual precipitation events. Only in regions, where all the moisture evaporates from the ground already in spring, the intensity of precipitation events is reduced in summer.  相似文献   

Understanding Design with VGI using an Information Relevance Framework     

Christopher J. Parker  Andrew May  Val Mitchell 《Transactions in GIS》2012,16(4):545-560

Volunteered Geographic Information (VGI) has the potential to offer benefits to end‐users over and above those of Professional Geographic Information (PGI). A multi‐methods approach, consisting of participatory observation, focus groups and diary studies, was used to study how VGI and PGI were actually used by a target user group. A theoretical framework of information relevance was used to understand the attributes of information that were most important in relation to the characteristics of the users' activity and their community. The key finding was that the discussion amongst GIS designers should not be whether to choose VGI or PGI as the information data set, but to consider which combination of VGI and PGI relating to different geographic features and task characteristics would best meet the users' needs. VGI is likely to be most relevant to the user when a geographic feature is dynamic rather than static in nature, and can also provide a level of detail that is unlikely to arise through PGI. These findings have implications for how different forms of information are most effective for different usage situations. Above all, a case is presented for the implementation of User Centred Design (UCD) principles when integrating VGI and PGI together in a single mashup‐based product.  相似文献   

A Spatiotemporal GIS Framework Applied to the Analysis of Changes in Temperature Patterns     

James Bothwell  May Yuan 《Transactions in GIS》2012,16(6):901-919

This research develops a new temporal Geographic Information System (GIS) framework and applies it to compare General Circulation Model (GCM) products and reanalysis datasets in order to discern differences in patterns and locations of change as a proof of concept. The proposed framework incorporates the concept of kinematics to represent the movement of isolines as advection displacement vectors. Comparison of displacement vectors from the four datasets shows differences in isotherm shifts for both median values and interquartile ranges along with several prominent, well defined difference regions across the globe. Among the four datasets used in the study, the two reanalysis datasets have the smallest median difference in displacement vectors indicating the least spatiotemporal difference. As both reanalysis datasets are based on actual observations, this result validates the displacement vector representation. The CNRM CM3 20C3M dataset contains an Antarctic Cooling that led to most of the differences in displacement vectors against the other datasets. The research shows the effectiveness of GIS enabled displacement vectors analysis to elicit spatial differences in climate patterns among GCM data and reanalysis data. While temperature data were used in the case study, the proposed method is based on concepts applicable to other isolines of geographic variables (such as isobars or isohyets).  相似文献   

Star-forming region BBW 36 in puppis     

A. L. Gyulbudahgian  J. May 《Astrophysics》2008,51(3):394-402

Recent studies of the star formation region BBW 36 and associated molecular clouds are presented. The ¹²CO (1-0) observations, carried out with the 15-m SEST (Swedish-ESO) telescope (Cerro La Silla, Chile), revealed the existence of cloud a, connected with BBW 36 and of cloud b, having elongation in SE-NW direction. A red-shifted molecular outflow with velocity ∼+5 km/s (with respect to cloud a), having a direction parallel to the line of sight, was also observed. VLA observations showed the presence of a source VLA 2 at 3.6 cm with an elongation in the N-S direction. It is suggested that the VLA 2 source coincides with a dust disc (surrounding the object BBW 36). The star 3, which is one of the YSOs in the star-forming region BBW 36 and is connected with a bright comma-like nebula, can be the source of the molecular outflow. The star 3 has very high IR colors and is associated with an IRAS point source IRAS 07280-1829, which has IR colors, typical for an IRAS point source, connected with a water maser. On the 2MASS K image of BBW 36 we can see the existence of a bright nebula; a group of stars is embedded in that nebula, and among these stars there are stars with dust discs (or envelopes). On the 2MASS K image several spiral jets are also present, some of them with a condensation at the end. Published in Astrofizika, Vol. 51, No. 3, pp. 469–477 (August 2008).  相似文献   

Erratum to: Climate change under aggressive mitigation: the ENSEMBLES multi-model experiment     

T. C. Johns  J.-F. Royer  I. Höschel  H. Huebener  E. Roeckner  E. Manzini  W. May  J.-L. Dufresne  O. H. Otterå  D. P. van Vuuren  D. Salas y Melia  M. A. Giorgetta  S. Denvil  S. Yang  P. G. Fogli  J. Körper  J. F. Tjiputra  E. Stehfest  C. D. Hewitt 《Climate Dynamics》2011,37(5-6):1269-1270

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