Sökning: "NATURAL SCIENCES Earth sciences Atmosphere and hydrosphere sciences Meteorology"

Visar resultat 1 - 5 av 9 avhandlingar innehållade orden NATURAL SCIENCES Earth sciences Atmosphere and hydrosphere sciences Meteorology.

1. 1. The influence of clouds on Earth's radiation budget in global climate models

   Författare :Johannes Karlsson; Gunilla Svensson; Henning Rodhe; Bjorn Stevens; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Atmosphere and hydrosphere sciences; Atmosfärs- och hydrosfärsvetenskap; Meteorology; Meteorologi; Oceanography; Oceanografi; atmosfärvetenskap och oceanografi; Atmospheric Sciences and Oceanography;

   Sammanfattning : Considering the high sensitivity of climate to changes in cloudiness, the way clouds might change in a perturbed climate is important for the total temperature response. In fact, the cloud feedback has been identified as the main uncertainty in future projections, as simulated by global climate models. LÄS MER

3. 2. Regional studies of the optical, chemical and microphysical properties of atmospheric aerosols : Radiative impacts and cloud formation

   Författare :Admir Créso Targino; Douglas Nilsson; Radovan Krejci; Richard Leaitch; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; atmospheric aerosols; particles; optical properties; cloud; ice crystals; chemical composition; Atmosphere and hydrosphere sciences; Atmosfärs- och hydrosfärsvetenskap;

   Sammanfattning : Atmospheric particles are ubiquitous in the Earth’s atmosphere and have potential to influence atmospheric chemistry, visibility, global climate and human health, particularly downwind from major pollution sources. The main objective of this thesis was to investigate questions pertaining to the microphysical, chemical and optical properties of aerosol particles by using in situ data collected during four experiments carried out in different regions of the Northern Hemisphere. LÄS MER

4. 3. Properties and Origin of Arctic Aerosols

   Författare :Ann-Christine Engvall; Jörg Gumbel; Frode Stordal; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Arctic aerosols; Arctic troposphere; air-mass transport; Atmosphere and hydrosphere sciences; Atmosfärs- och hydrosfärsvetenskap; atmosfärvetenskap; Atmospheric Sciences;

   Sammanfattning : The present thesis deals with the origin and physics of aerosols in the Arctic atmosphere. These show a large annual variability due to changes of the photochemical and cloud processes as well as of the synoptic-scale atmospheric pressure patterns. LÄS MER

5. 4. Meteoric Aerosols in the Middle Atmosphere

   Författare :Linda Megner; Jörg Gumbel; Martin Ridal; Gary E. Thomas; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; meteoroid; meteor; nucleation; mesosphere; stratosphere; ablation; smoke; NLC; PMSE; PSC; Atmosphere and hydrosphere sciences; Atmosfärs- och hydrosfärsvetenskap; atmosfärvetenskap; Atmospheric Sciences;

   Sammanfattning : This thesis concerns the fate of the meteoric smoke in the Middle Atmosphere, and its effect on ice phenomena such as noctilucent clouds (NLC) and polar stratospheric clouds (PSC). The potential role of NLC as tracer for mesospheric processes and variability, and as a tool for monitoring this remote and inaccessible region, has generated substantial interest within the scientific community. LÄS MER

7. 5. Submicrometre aerosol emissions from sea spray and road traffic

   Författare :Monica Mårtensson; Douglas Nilsson; Christer Johansson; Michael Smith; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Eddy covariance method; aerosol emissions; submicrometre sea salt parameterisation; primary marine organic aerosols; sea spray; road traffic emission factors; air-sea exchange; aerosol dynamics model; internal aerosol mixing; combustion aerosols; Atmosphere and hydrosphere sciences; Atmosfärs- och hydrosfärsvetenskap; atmosfärvetenskap; Atmospheric Sciences;

   Sammanfattning : The uncertainty of the climate and health effects of aerosols is still large, one important reason being lack of knowledge of the primary emissions. This thesis combines laboratory and field experiments, and process modelling in an effort to better quantify the submicrometre aerosol emissions and to understand some of the processes in the atmosphere. LÄS MER