Sökning: "atmospheric stability"

Visar resultat 21 - 25 av 69 avhandlingar innehållade orden atmospheric stability.

1. 21. Computational fluid dynamics for dispersion calculation in urban surroundings

   Författare :Jan Burman; Anna Rutgersson; Sven-Erik Gryning; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; CFD; RANS; LES; Toxicological effects; Synthetic boundary conditions; Stable boundary layer.; Meteorologi; Meteorology;

   Sammanfattning : Increased knowledge on dispersion processes in urban environment will enhance the ability in the society to handle events where releases of toxic substances can occur. Also, the ability to increase preparedness at locations where such events potentially can emerge. LÄS MER

3. 22. Determination of mercury chemical speciation in the presence of low molecular mass thiols and its importance for mercury methylation

   Författare :Van Liem-Nguyen; Erik Björn; Ulf Skyllberg; Cynthia Gilmour; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Mercury; methylmercury; LMM thiol; mass spectrometry; biogeochemistry; soil; sediment; ICP; WinSGW; modeling; S XANES; ligand exchange; stability constant; boreal wetlands; analytisk kemi; Analytical Chemistry; Environmental Science; miljövetenskap;

   Sammanfattning : Methylmercury (MeHg) is a neurotoxic compound that threatens the well-being of humans and wildlife. It is formed through the methylation of inorganic mercury (HgII) under suboxic/anoxic conditions in soils, sediment and waters. LÄS MER

4. 23. Earth's albedo in a changing climate

   Författare :Frida A-M Bender; Henning Rodhe; Annica Ekman; William Collins; Stockholms universitet; []
   Nyckelord :albedo; Earth s radiative budget; cloud properties; climate sensitivity; CMIP3; GCMs; satellite observations; NATURAL SCIENCES; NATURVETENSKAP; atmosfärvetenskap; Atmospheric Sciences;

   Sammanfattning : The albedo is a key parameter in the radiative budget of the Earth and a primary determinant of the planetary temperature and is therefore also central to questions regarding climate stability, climate change and climate sensitivity. Climate models and satellite observations are essential for studying the albedo, and the parameters determining it, on large spatial and temporal scales. LÄS MER

5. 24. Atmospheric pressure ionisation interface considerations for micro column separation with mass spectrometric detection

   Författare :Per J. R. Sjöberg; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Chemistry; Kemi; Chemistry; Kemi; Analytical Chemistry; analytisk kemi;

   Sammanfattning : Two miniaturised atmospheric pressure chemical ionisation (APCI) interfaces were developed for micro column separation and their performances were investigated in high temperature open tubular column liquid chromatography and capillary supercritical fluid chromatography (SFC). The most influential parameters, for example, the interface probe position relative to the sampling orifice and the reagent ion plasma composition, were investigated to optimise the ion current signal and stability. LÄS MER

7. 25. The Ups and Downs of the Holocene: Exploring Relationships between Global CO2 and Climate Variability in the North Atlantic Region

   Författare :Catherine Jessen; Kvartärgeologi; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; marklära; geomorfologi; climatology; klimatologi; rapid climate change; Holocene climate; atmospheric CO2 concentrations; geochemical proxy indicators; Paleobotanik; palynology; Geology; palynologi; fylogeni; geomorphology; fysisk geografi; Geologi; physical geography; kartografi; pedology; cartography; phylogeny; Palaeobotany; stomatal frequency; lake sediments;

   Sammanfattning : This thesis aimed to examine the relationship between climate and atmospheric CO2 concentrations through rapid climate changes during the Holocene. Climate was reconstructed using high-resolution, radiocarbon dated, lake sediment geochemical proxies (magnetic susceptibility, loss-on-ignition, total carbon/nitrogen/sulphur determinations and biogenic silica), vegetational reconstruction (pollen analysis) and stomatal frequency based CO2 reconstructions. LÄS MER