نتایج جستجو برای: mountain climate
تعداد نتایج: 193911 فیلتر نتایج به سال:
[1] Disparate climate proxies from theNorthernHemisphere record a climate event at 4.2–3.8 ka. Here we show that glaciers throughout the mountain ranges of western Canada advanced at about this time. This conclusion is based on (1) new and previously reported radiocarbon ages on in situ stumps, logs, branches, and soils exposed by recent retreat in glacier forefields and (2) clastic-rich sedime...
Effects of roads on plant communities are not well known in cold-climate mountain ecosystems, where road building and development are expected to increase in future decades. Knowledge of the sensitivity of mountain plant communities to disturbance by roads is however important for future conservation purposes. We investigate the effects of roads on species richness and composition, including th...
A multidimensional, mountain-scale, thermal-hydrologic (TH) numerical model is presented for investigating unsaturated flow behavior in response to decay heat from the proposed radioactive waste repository in the Yucca Mountain unsaturated zone (UZ), The model, consisting of both two-dimensional (2-D) and three-dimensional (3-D) representations of the UZ repository system, is based on the curre...
This study investigated the influences of geographic isolation and climate fluctuation on the genetic diversity, speciation, and biogeography of the genus Pseudovelia (Hemiptera: Veliidae) in subtropical China and tropic Indo-China Peninsula. Species nucleotide and haplotype diversities decreased with reduction in species distribution limits. The gene tree was congruent with the taxonomy of mon...
Postglacial climate changes alter geographical distributions and diversity of species. Such ongoing changes often force species to migrate along the latitude/altitude. Altitudinal gradients represent assemblage of environmental, especially climatic, variable factors that influence the plant distributions. Global warming that triggered upward migrations has therefore impacted the alpine plants o...
Apart from the overwhelming cases of allopolyploidization, the impact of speciation through homoploid hybridization is becoming more relevant than previously thought. Much less is known, however, about the impact of climate changes as a driven factor of speciation. To investigate these issues, we selected Festuca picoeuropeana, an hypothetical natural hybrid between the diploid species F. eskia...
The spatial variation of soil physical and chemical properties in Funiu Mountain was studied to provide references for identifying soil spatial variation mechanism in bordering land of China warm temperate zone and northern subtropical region. Using vertical gradient sampling and traditional statistics method, the soil samples at the altitude from 1640 m to 1870 m were collected to compare phys...
Global warming induced changes in extreme orographic precipitation are investigated using a hierarchy of models: a global climate model, a limitedarea weather forecast model, and a linear mountain-wave model. We consider precipitation changes over an idealized north-south mid-latitude mountain barrier at the western margin of an otherwise flat continent. The intensities of the extreme events on...
Palynological analyses from exposed palaeolacustrine deposits located at the flanks of Damavand volcano, in the central AlborzMountains in Northern Iran, provide a broad idea of the temporal variation of vegetation according to climate changes during a rangeof limited time intervals during the Quaternary period. This research reveals that the regional vegetation of the study area had been asemi...
Previously published isoline maps of Fennoscandian timberlines show that their highest elevations lie in the high mountain areas in central south Norway and from there the limits decrease in all directions. These maps are assumed to show differences in “climatic forest limits”, but the isoline patterns indicate that factors other than climate may be decisive in most of the areas. Possibly the e...
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