inscription
PORTAIL D'INFORMATION GÉOGRAPHIQUE

Résultats de la recherche (175 résultats)

Affinez votre recherche

Par Collection Par Auteur Par Date Par Sujet Par Titre Par ville ? Par pays ? Par continent ?
  • The importance of natural variability in lake areas on the detection of permafrost degradation : A case study in the Yukon Flats, Alaska
  • Alaska ; Climatic variability ; Environmental degradation ; Interannual variability ; LANDSAT ; Lake ; Periglacial features ; Permafrost ; Remote sensing ; Water balance
  • Alaska ; Balance hidrológico ; Degradación del medio ambiente ; LANDSAT ; Lago ; Pergelisol ; Periglaciar ; Teledetección ; Variabilidad climática ; Variabilidad interanual
  • In order to better understand the natural background variability of lake areas, the AA. used Landsat 7 images obtained on 11 dates from 1999 to 2002 to quantify the intra- and interannual lake area variability for a 4224 km2 study area within
  • the Yukon Flats. Both intra- and interannual area variability in August and September were smaller than in June and July, suggesting that images from later in summer are more reliable for detecting long-term change in lake area. Variability of no-closure
  • 2013
  • Response of savanna gross primary productivity to interannual variability in rainfall : Results of a remote sensing based light use efficiency model
  • Australia ; Biomass ; Carbon cycle ; Climatic change ; Climatic variability ; Interannual variability ; Northern Territory ; Plant cover ; Precipitation ; Remote sensing ; Satellite imagery ; Savanna
  • Australia ; Biomasa ; Cambio climático ; Ciclo del carbono ; Cobertura vegetal ; Imagen satélite ; Precipitación ; Sabana ; Teledetección ; Variabilidad climática ; Variabilidad interanual
  • biome and show the sensitivity of different vegetation systems to rainfall, a variable that may change in quantity and variability with projected climate change. Such data also show regions of high levels of carbon that could be linked with savanna
  • 2013
  • Change of parameters of BCC/RCG-WG for daily non-precipitation variables in China : 1951-1978 and 1979-2007
  • China ; Climate ; Climatic change ; Climatic data ; Interannual variability ; Seasonal cycle ; Solar radiation ; Temperature
  • Cambio climático ; China ; Clima ; Dato climático ; Radiación solar ; Temperatura ; Variabilidad interanual
  • to 2007 respectively. The changes in the parameters for the 2 periods are revealed to explore the impact of climate change on these parameters. While the annual means and the amplitudes of the seasonal cycle show a clear change, the interannual variability
  • Parameters of weather generator BCC/RCG-WG for daily non-precipitation variables including maximum temperature, minimum temperature and sunshine hours at 669 stations in China are estimated using history daily records from 1951 to 1978 and from 1979
  • , the timings of the seasonal cycles, and the temporal correlations for each variable remain practically unchanged. This indicates that climate changes in China over the last 57 years are mainly reflected in variations in the means and in the strength
  • 2013
  • 1980-2010 variability in UK surface wind climate
  • Applied climatology ; Energy ; Energy potential ; Interannual variability ; United Kingdom ; Wind ; Wind energy ; Wind speed
  • Climatología aplicada ; Energía ; Energía eólica ; Reino Unido ; Variabilidad interanual ; Velocidad del viento ; Viento
  • 2013
  • Air temperature ; Atmospheric circulation ; Climatic data ; Climatic variability ; Climatology ; Interannual variability ; Poland ; Seasonal variability ; Spatial distribution ; Thawing
  • Circulación atmosférica ; Climatología ; Dato climático ; Deshielo ; Distribución espacial ; Polonia ; Temperatura del aire ; Variabilidad climática ; Variabilidad estacional ; Variabilidad interanual
  • The study is concerned with the temporal and spatial characterisation of atmospheric thaw variability in Poland. The phenomenon was described on the basis of mean daily values of air temperature for the winter months October-March over the period
  • in the north-west. The spatial distribution of thaw is strongly dependent on longitude and less on height above sea level. Multiyear variability of thaw days is determined by atmospheric circulation. The role of circulation expressed by NAO index
  • in the explanation of the variability of thaw occurrence was statistically insignificant.
  • 2013
  • Atmospheric circulation ; Climate ; Interannual variability ; Orographic effect ; Patagonia ; Precipitation ; South America ; Spatial differentiation ; Temperature
  • América del Sur ; Circulación atmosférica ; Clima ; Diferenciación espacial ; Efecto orográfico ; Precipitación ; Temperatura ; Variabilidad interanual
  • 2013
  • Africa ; Atmospheric circulation ; Interannual variability ; Model ; Monsoon ; Precipitation ; Sahel ; Simulation ; Spatial distribution ; Temperature ; West Africa
  • Circulación atmosférica ; Distribución espacial ; Modelo ; Monzón ; Precipitación ; Sahel ; Simulación ; Temperatura ; Variabilidad interanual ; África ; África del Oeste
  • 2013
  • Climatic zone ; Hydrology ; Interannual variability ; Pacific Ocean ; Salinity ; Seasonality ; Water budget ; Water mass
  • Balance hídrico ; Estacionalidad ; Hidrología ; Masa de agua ; Océano Pacífico ; Salinidad ; Variabilidad interanual ; Zona climática
  • 2013
  • Active layer ; Air temperature ; Arctic Region ; Climate ; Cloud cover ; Interannual variability ; Ocean atmosphere interaction ; Periglacial features ; Permafrost ; Precipitation ; Svalbard
  • Clima ; Interaccíon océano-atmósfera ; Molisol ; Nebulosidad ; Pergelisol ; Periglaciar ; Precipitación ; Temperatura del aire ; Variabilidad interanual ; Ártica
  • 2013
  • Using synthetic variables in instrumental variable estimation of spatial series models
  • Analyse spatiale ; Autocorrélation spatiale ; Données spatiales ; Eigenvecteur ; Filtre spatial ; Simulation ; Statistique ; Série spatiale ; Variable instrumentale ; Variable synthétique
  • This paper explores the use of synthetic variables in IV estimation when the analysis is of spatial data series. It considers two situations of interest: first, the case where there are no clear candidates for instrumentation and the instruments
  • are comprised of purely synthetic variables; second, the case when there are substantive but weak instruments that can be enhanced by the addition of synthetic variables. The approach proposed is illustrated with an empirical example.
  • 2013
  • Exploring the role of rainfall variability and extreme events in long-term landscape development
  • Climatic variability ; Land use ; Model ; Murcia ; Precipitation ; Semi-arid area ; Simulation ; Soil erosion ; Spain ; Storm ; Water erosion
  • and shortening the timescales for which each model was developed. The erosion effects of rainfall variability, climate and land use change were explored on a centennial timescale. Results show non-linear behaviour between rainfall input and simulated net erosion
  • . Simulated net erosion for increased rainfall erosivity was compared to rainfall variability, showing that mean annual net erosion of up to 15% increased erosivity is not significantly different from annual mean net erosion of the original simulations. Single
  • events must be of very high magnitude and/or frequency to leave a signal in the landscape that is beyond the scope of natural rainfall variability. Scenarios of human impact show that land use changes can have a potentially larger effect on erosion
  • dynamics than climate variability and change.
  • 2013
  • Global air temperature variability independent of sea-surface temperature influences
  • Climatic change ; Climatic variability ; Climatic warming ; Global change ; Ocean atmosphere interaction ; Principal components analysis ; Surface temperature ; Temperature ; Time series
  • The AA. review the key recent literature on connections between mean global surface air temperature (SAT) and sea surface temperature (SST) variability on timescales ranging from annual to multi-decadal. Although individual ocean influences on SAT
  • have been recognized, the combined contributions of worldwide SST variability on the global SAT signal have not been clearly identified in observed data. The AA. analyze these relations using principal components of detrended SST, and find that removing
  • the underlying combined annual, decadal, and multi-decadal SST variability from the SAT time series reveals a nearly monotonic global warming trend in SAT since about 1900.
  • 2013
  • An analysis of intra-event precipitation variability for the United States (1980–2010)
  • Climatic data ; Climatic variability ; Climatology ; Precipitation ; Rainstorm ; Spatial distribution ; Statistical analysis ; United States of America
  • Hourly precipitation data were collected from 143 first-order US weather stations during the period from 1980 to 2009 to assess the internal distribution of precipitation events lasting at least 3 hours. Here, the AA. examine the spatial variability
  • differentiation between types of storms and provide additional insight into storm event variability, possibly assisting in water management, flood control, and engineering studies.
  • 2013
  • Climate variability and trends in Bolivia
  • Bolivia ; Climate ; Climatic trend ; Climatic variability ; Climatic variation ; Precipitation ; Teleconnection ; Temperature
  • 2013
  • Variability of air mass occurrence in southern Poland (1951-2010)
  • Air mass ; Atmospheric dynamics ; Classification ; Poland ; Seasonal variability ; South-Eastern Poland ; Statistical analysis ; Statistics
  • 2013
  • Evaluating channel response to an extreme sedimentation event in the context of historical range of variability : Upper Colorado River, USA
  • . The AA. present a proof of concept to understand whether the 2003 disturbance is within the historical range of variability (HRV), and whether the recovery potential of the system is sufficient to adapt to the disturbance. Flow and sediment regimes
  • is returning to a condition of natural variability, but the Colorado River is outside the HRV expected for steep-gradient, pool-riffle channels. Applying HRV to a situation where management questions require a longer term perspective, and pre-disturbance
  • 2013
  • El estudio de las variables demográficas en la Sierra Morena Cordobesa según las fuentes precensales
  • L'étude des variables démographiques dans la Sierra Morena de Cordoue d'après les sources du pré-recensement
  • caractériser les variables démographiques puis de mettre en évidence les similitudes et les différences au niveau provincial et régional. Les résultats indiquent une expansion démographique au XVIème siècle, suivie d’une crise démographique au siècle suivant à
  • 2013
  • Multidecadal variability in local growing season during 1901–2009
  • 2013
  • Coping with climate variability and change in research for development targeting West Africa : need for paradigm changes
  • 2013
  • Trends and variability in extreme precipitation indices over Maghreb countries
  • 2013