30 research outputs found
Modeling the Location of the Forest Line in Northeast European Russia with Remotely Sensed Vegetation and GIS-Based Climate and Terrain Data
GIS-based data sets were used to analyze the structure of the forest line at the landscape level in the lowlands of the Usa River Basin, in northeast European Russia. Vegetation zones in the area range from taiga in the south to forest-tundra and tundra in the north. We constructed logistic regression models to predict forest location at spatial scales varying from 1 × 1 km to 25 × 25 km grid cells. Forest location was explained by July mean temperature, ground temperature (permafrost), yearly minimum temperature, and a Topographic Wetness Index (soil moisture conditions). According to the models, the forest line follows the +13.9°C mean July temperature isoline, whereas in other parts of the Arctic it usually is located between +10 to +12°C. It is hypothesized that the anomalously high temperature isoline for the forest line in Northeast European Russia is due to the inability of local ecotypes of spruce to grow on permafrost terrain. Observed patterns depend on spatial scale, as the relative significance of the explanatory variables varies between models implemented at different scales. Developed models indicate that with climate warming of 3°C by the end of the 21st century temperature would not limit forest advance anywhere in our study area
Studies of changes in the activity of dissolved oxygen in the simulation of ferromanganese filtration
The article deals with the solution of an urgent problem related to the process of filtration refining of ferroalloys. Based on the data obtained, it was found that combining the filtration process with casting ensures the flow of refined melt directly into the mold cavity and partial or complete elimination of secondary oxidation. To identify the underlying mechanism of filtration refining, the interaction of liquid metal with the filter in its separate pore channel was simulated. The main technological parameters of the process under consideration are calculated and practically confirmed
Studies of changes in the activity of dissolved oxygen in the simulation of ferromanganese filtration
The article deals with the solution of an urgent problem related to the process of filtration refining of ferroalloys. Based on the data obtained, it was found that combining the filtration process with casting ensures the flow of refined melt directly into the mold cavity and partial or complete elimination of secondary oxidation. To identify the underlying mechanism of filtration refining, the interaction of liquid metal with the filter in its separate pore channel was simulated. The main technological parameters of the process under consideration are calculated and practically confirmed
The disappearing cryosphere : impacts and ecosystem responses to rapid cryosphere loss
Author Posting. © American Institute of Biological Sciences, 2012. This article is posted here by permission of American Institute of Biological Sciences for personal use, not for redistribution. The definitive version was published in BioScience 62 (2012): 405-415, doi:10.1525/bio.2012.62.4.11.The cryosphere—the portion of the Earth's surface where water is in solid form for at least one month of the year—has been shrinking in response to climate warming. The extents of sea ice, snow, and glaciers, for example, have been decreasing. In response, the ecosystems within the cryosphere and those that depend on the cryosphere have been changing. We identify two principal aspects of ecosystem-level responses to cryosphere loss: (1) trophodynamic alterations resulting from the loss of habitat and species loss or replacement and (2) changes in the rates and mechanisms of biogeochemical storage and cycling of carbon and nutrients, caused by changes in physical forcings or ecological community functioning. These changes affect biota in positive or negative ways, depending on how they interact with the cryosphere. The important outcome, however, is the change and the response the human social system (infrastructure, food, water, recreation) will have to that change.The authors wish to thank the funding provided by the
National Science Foundation’s (NSF) Long Term Ecological
Research (LTER) Network for supporting our long-term
studies, in which we track the ecosystem response to the disappearing
cryosphere. NSF LTER Site Grants OPP 0823101, OPP
1115245, DEB 1114804, DEB-1026415, DEB-0620579, and
DEB-1027341 supported the authors during the preparation
of this article.2012-10-0
PECULIAR TEMPERATURE REGIME IN COLD FROZEN SOILS ALONG THE SOUTHERN BOUNDARY OF THE CRYOLITHOZONE IN THE NORTH-EAST OF EUROPEAN RUSSIA
Under study was the temperature regime of frozen soils situated along the southern boundary of cryolithozone in the North-East of European Russia. In southern tundra the frozen soils with the cold temperature regime are confined to peat and mineral parent materials. The seasonal and long-term temperature dynamics in seasonal-thawing and underlying permafrost-affected layer is shown. The frozen soils are characterized by the main temperature indices