Sökning: "net ecosystem exchange"

Visar resultat 1 - 5 av 16 avhandlingar innehållade orden net ecosystem exchange.

  1. 1. 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

  3. 2. 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

  4. 3. Surface energy exchange and land-atmosphere interactions of Arctic and subarctic tundra ecosystems under climate change

    Författare :Christian Stiegler; Institutionen för naturgeografi och ekosystemvetenskap; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Surface energy exchange; Arctic and subarctic tundra; climate change; permafrost; eddy covariance; snow cover; micrometeorology;

    Sammanfattning : The surface energy balance determines the functioning of any ecosystem on the Earth but is still poorly understood in Arctic and subarctic biomes. In a dynamic system, such as the Earth’s climate, any change in its characteristics modifies the exchange of energy, water, and greenhouse gases between the surface and the atmosphere. LÄS MER

  5. 4. Effects of future climate on carbon assimilation of boreal Norway spruce

    Författare :Marianne Hall; Göteborgs universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; bud development; climate change; empirical models; gas exchange; photosynthesis; Picea abies; seasonality; whole-tree chambers;

    Sammanfattning : In boreal forests, the main factors limiting biomass production are the harsh climate, which combines a short growing season and low annual levels of incoming solar energy, and the limited availabilit... mery of nitrogen. LÄS MER

  7. 5. Tundra meets atmosphere : Seasonal dynamics of trace gas exchange in the High Arctic

    Författare :Norbert Pirk; Institutionen för naturgeografi och ekosystemvetenskap; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Arctic; tundra; methane; carbon dioxide;

    Sammanfattning : Arctic environments have experienced strong warming in recent decades, which is affecting the carbon cycle of tundra ecosystems.Degrading permafrost, diminishing snow cover, and changing hydrology are examples of ongoing processes that affect the land-atmosphere interactions and seasonal ecosystem dynamics. LÄS MER