Sökning: "Per-Erik Jansson"

Visar resultat 21 - 24 av 24 avhandlingar innehållade orden Per-Erik Jansson.

  1. 21. Water, Heat and Solute processes in Seasonally frozen Soils : Experimental and Modeling Study

    Författare :Mousong Wu; Per-Erik Jansson; Jiesheng Huang; Klas Hansson; David Gustafsson; Nicholas Jarvis; KTH; []
    Nyckelord :LANTBRUKSVETENSKAPER; AGRICULTURAL SCIENCES; frozen soil; water-heat-solute transport; coupled effects; water and energy balance; uncertainties; 冻土；水热盐运移；耦合关系；水热平衡；不确定性; Mark- och vattenteknik; Land and Water Resources Engineering;

    Sammanfattning : Soil freezing and thawing is of importance in transport of water, heat and solute, which has coupled effects. Solute type and solute content in frozen soil could influence the osmotic potential of frozen soil and decrease freezing point, resulting in differences in soil freezing characteristic curves under various solute conditions. LÄS MER

  3. 22. Impact of cold climate on boreal ecosystem processes : exploring data and model uncertainties

    Författare :Sihong Wu; Per-Erik Jansson; Annikki Mäkelä; KTH; []
    Nyckelord :LANTBRUKSVETENSKAPER; AGRICULTURAL SCIENCES; net ecosystem exchange; sensible and latent heat fluxes; soil temperature; soil moisture; CoupModel; GLUE;

    Sammanfattning : The impact of cold climate on physical and biological processes, especially the role of air and soil temperature in recovering photosynthesis and transpiration in boreal forests, was investigated in a series of studies. A process-based ecosystem model (CoupModel) considering atmospheric, soil and plant components was evaluated and developed using Generalized Likelihood Uncertainty Estimation (GLUE) and detailed measurements from three different sites. LÄS MER

  4. 23. Modeling the Seasonality of Carbon, Evapotranspiration and Heat Processes for Cold Climate Conditions

    Författare :Sihong Wu; Per-Erik Jansson; Andreas Ibröm; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; net ecosystem exchange NEE ; sensible and latent heat fluxes; photosynthesis; respiration; nitrogen turnover; Scots pine forest; bare soil; cold climate; soil physical characteristics; CoupModel; GLUE; Other civil engineering and architecture; Övrig samhällsbyggnadsteknik och arkitektur;

    Sammanfattning : The productivity of agricultural and forest ecosystems in regions at higher latitudes is to a large extent governed by low temperature and moisture conditions. Environmental conditions are acting both above- and below-ground and regulating carbon fluxes and evapotranspiration. LÄS MER

  5. 24. Connecting the dots : Network analysis, landscape ecology, and practical application

    Författare :Andreas Zetterberg; Berit Balfors; Ulla Mörtberg; Per-Erik Jansson; Sandra Luque; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Landscape connectivity; Land-use planning; Urban and regional planning; Graph theory; Network analysis; Environmental assessment; Least-cost modeling; Biodiversity;

    Sammanfattning : Humans have a profound impact on ecosystems, and land-use change constitutes a primary driving force in the loss of biodiversity. Habitat loss and fragmentation are key factors in this process by seriously impeding the habitat availability and movement of species, leading to a significant decrease in population viability. LÄS MER