Sökning: "brown carbon"

Visar resultat 1 - 5 av 27 avhandlingar innehållade orden brown carbon.

  1. 1. Temporal and spatial dynamics in subarctic peat plateaus and thermokarst lakes

    Författare :A. Britta K. Sannel; Peter Kuhry; Peter Jansson; Ian A. Brown; Serge Payette; Stockholms universitet; []
    Nyckelord :Peatlands; permafrost; subarctic; peat plateau; thermokarst lake; macrofossil analysis; carbon nitrogen ratio; peat accumulation; carbon accumulation; remote sensing; binary encoding; time-series analysis; Physical Geography; naturgeografi;

    Sammanfattning : Permafrost peatlands are widespread at high northern latitudes and are important soil organic carbon reservoirs. A future warming in these areas, as suggested by global climate models, can cause thawing and increased ground subsidence (thermokarst), resulting in changes in surface hydrology and ecosystem functioning. LÄS MER

  2. 2. Holocene dynamics in subarctic peat plateaus of west-central Canada : Vegetation succession, peat accumulation and permafrost history

    Författare :A. Britta K. Sannel; Peter Kuhry; Peter Jansson; Ian Brown; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; peatlands; permafrost; carbon accumulation; fire; subarctic; Holocene; Physical geography; Naturgeografi;

    Sammanfattning : Dynamics in vegetation, permafrost and peat and net carbon accumulation rates throughout the Holocene have been studied in two subarctic peat plateaus of west-central Canada through plant macrofossil analysis, geochemical analyses and AMS radiocarbon dating. Peatland formation at the studied sites began around 6600-5900 cal yr BP as a result of paludification of upland forests. LÄS MER

  3. 3. Diagnosis of the Lifetime Performance Degradation of Lithium-Ion Batteries : Focus on Power-Assist Hybrid Electric Vehicle and Low-Earth-Orbit Satellite Applications

    Författare :Shelley Brown; Göran Lindbergh; Robert Spotnitz; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; lithium-ion battery; LixNi0.8Co0.15Al0.05O2; LixMn2O4; LiyC6; ageing; three-electrode measurements; impedance modelling; surface film characterisation; hybrid electric vehicle; low-earth-orbit satellite; litiumjonbatteri; åldring; treelektroduppställning; impedansmodell; ytfilmskarakterisering; hybridfordon; satelliter; Electrochemistry; Elektrokemi;

    Sammanfattning : Lithium-ion batteries are a possible choice for the energy storage system onboard hybrid electric vehicles and low-earth-orbit satellites, but lifetime performance remains an issue. The challenge is to diagnose the effects of ageing and then investigate the dependence of the magnitude of the deterioration on different accelerating factors (e.g. LÄS MER

  4. 4. Formation and Transformation of Atmospheric Brown Carbon (BrC)

    Författare :Kalyan Mitra; Göteborgs universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; brown carbon BrC ; primary organic aerosol POA ; secondary organic aerosol SOA ; BrC bleaching; BrC browning; Toluene photo-oxidation; NOx; Ammonia; NH3; acidity effects; light absorption;

    Sammanfattning : Atmospheric brown carbon (BrC) aerosol absorbs light in the UV-Vis spectrum and has poorly constrained but potentially large climate forcing impacts. Most current climate models lack detailed chemistry and interlinked properties of atmospheric BrC, that induce large uncertainties in radiative forcing predictions. LÄS MER

  5. 5. Carbon metabolism in clear-water and brown-water lakes

    Författare :Jenny Ask; Jan Karlsson; Mats Jansson; Rolf Vinebrooke; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; clear-water lakes; brown-water lakes; primary production; bacterial production; benthic; pelagic; net ecosystem production; allochthonous organic carbon; CO2; DOC; Physical geography; Naturgeografi; Freshwater ecology; Limnisk ekologi; limnologi; Limnology; naturgeografi; Physical Geography;

    Sammanfattning : The trophic state of lakes is commonly defined by the concentration of nutrients in the water column. High nutrient concentrations generate high phytoplankton production, and lakes with low nutrient concentrations are considered low-productive. LÄS MER