Résultats de la recherche (1237 résultats)

Affinez votre recherche

Par Collection Par Auteur Par Date Par Sujet Par Titre Par ville ? Par pays ? Par continent ?
  • The roles of texture and structure in the water retention capacity of burnt Mediterranean soils with varying rainfall
  • The objective of this work was to evaluate whether different soil conditions at burnt sites result from fire or from different climatic conditions (average annual precipitation). For this purpose, an altitudinal transect affected by forest fires
  • was chosen. Along the transect, 4 sites, with different amount of annual rainfall, but with almost homogeneous soil parent material, soil type and vegetation, were selected.
  • Annual variation ; Anticyclone ; Atmospheric circulation ; Climatic cycle ; Coastal environment ; Ocean atmosphere interaction ; Precipitation ; Seasonal variation ; South Africa ; Spatial variation ; Statistics ; Temperature inversion
  • Most climatological properties of first elevated inversions over southern Africa vary on annual cycles, although semi-annual cycles are prominent in base levels over the northern interior and in inversion strengths and frequencies. There are marked
  • Data on rainfall, runoff, soil moisture regime, and vegetation cover were collected at 5 monitoring sites in a sandy area along the Israeli-Egyptian border, where average annual rainfall varies from 86 to 160 mm. Results obtained cast doubt
  • of the prevailing idea regarding the positive relationship between average annual rainfall and ecosystem characteristics. The findings are attributed to the decisive role played by the non-uniform properties of the topsoil biological crusts along the rainfall
  • gradient considered. The process described may be regarded as a desertification process with increasing annual rainfall.
  • Climatic influence on the inter-annual variability of late-Holocene minerogenic sediment supply in a boreal forest catchment
  • . MinAR varies on annual to centennial scales and mainly reflects channel bank erosion by the inflow streams. The mineral input reflects the intensity of the spring run-off, which is dependent on the amount of snow accumulated during the winter, and hence
  • The sediment record at Kassjön (N. Sweden) consists of ∼6400 varves. Image analysis was used to determine grey-scale variation and varve thickness from which annual minerogenic accumulation rate (MinAR) was inferred for the period 4486 BC – AD 1900
  • and groundwater level. Extrapolation of the mean annual ground temperatures suggests that permafrost is unlikely present below an unfrozen talik, while it possibly disappeared within the last few decades. Soil moisture and groundwater level primary vary
  • with the annual frost regime and summer precipitation.
  • are different from the typical annual lamination. By analysing thin sections of sediment, debris flow events of the last 2250 years were reconstructed with an annual resolution. Since debris flow frequency varies strongly, periods with high and low frequencies
  • In this paper, 3 geostatistical algorithms (simple kriging with varying local means, kriging with an external drift, colocated ordinary cokriging) are introduced to incorporate an exhaustive secondary information (digital elevation model
  • ) into the spatial prediction of rainfall erosivity. The techniques are illustrated using annual and monthly rainfall data from the Algarve region in Portugal. Cross validation is used to compare the prediction performances of the 3 geostatistical interpolation
  • In this study, sample weights collected by 3 types of pressure-difference samplers are compared to determine whether differences are statistically significant. The implication of the results is that measured transport rates will vary depending
  • flow records and used to estimate annual yield. Discussion of the results.
  • The early and late Wisconsin maxima were times of prolonged annual sea-ice cover and a short cool period of phytoplankton productivity during the ice-free season. The middle Wisconsin interstade, at least in the southern Bering Sea, had greater
  • seasonal contrast than today, with some winter sea-ice cover, an intensified temperature minimum, and high spring productivity. Variations in clastic and reworked fossil material imply varying degrees of transport to the basin by Alaskan rivers.
  • In the strongly alkali profiles (solonchak-like type), annual soil moisture content only varied in the upper 50 cm layer. In the mildly alkali meadow and field soils variation reached down to 120 cm. This is explained by differences in water
  • The data were obtained on runoff ploto (100 m2) and from the outlet of the V. Spanilor hydrographic basin (206 ha) lying in the northwest of the Transylvanian Plateau. The value of annual erosion varies between 0.39 t. ha-1 and 11.0 t. ha-1
  • The seasonally varying monsoon circulations associated with the annual heating and cooling of the Asian continent are the most important large-scale aspects of the general circulation of the atmosphere. The Indian summer monsoon affects the lives
  • Do gasoline demand elasticities vary?
  • (Vorkarwendel). The proportion of erosion by runoff on slopes of the sediment yields of the catchment areas during individual precipitation events varies widely. In the annual balance of solids, erosion in channels and sediment yields predominate over erosion
  • Time series of annual Mean Tidal Range (MTR) have been assembled from 13 ports around the British Isles and secular trends in MTR computed at each site. Trends vary between −1,8 and 1,3 mm/yr depending on location. At many sites the values
  • statistical model. Measures mean annual ground temperatures vary from near 0°C around 950m a.s.l. to -7°C at 2500m a.s.l. and permafrost is predicted to occur at elevations >700m a.s.l. Heat transfer modelling indicates that the maximum permafrost thickness
  • Runoff and sediment lost due to water erosion were recorded for 36 plots with varying types of vegetative cover located on sloping gypsiferous fields in the South of Madrid. Vegetative cover above 40% is capable of dissipating the relationship
  • between runoff and sediment loss, especially when the vegetative cover is greater than 60%. The soil here experiences a chronic loss of 0.02 mm annually as a consequence of frequent, moderate events, in addition to any loss produced by extraordinary events
  • This paper reports AMS C 14 ages of 10 bones and teeth of 3 species of large mammals from the Dutchess Quarry Caves, New York. Together with the Holocene conventional C 14 dates of charcoal and the varied stratigraphic proveniences of the fluted
  • , carnivores, and scavengers) and cryoturbation (annual freeze-thaw cycles).
  • heavy rainfall across the study area, but tropical disturbances and air-mass storms also contribute, especially at the more coastal locations. Annual regimes were found to vary dramatically from one site to another, and 7 of the 8 sites investigated