Sökning: "cloud condensation nuclei"

Visar resultat 21 - 25 av 30 avhandlingar innehållade orden cloud condensation nuclei.

1. 21. Development of GC-HRMS procedures for determination of naturally occuring polar compounds in various environmental applications

   Författare :Bodil Widell; Dag Broman; Caroline Leck; Joan Grimalt; Stockholms universitet; []
   Nyckelord :GC-HRMS; steroid hormones; amino acids; perch; size-resolved aerosol; Arctic; NATURAL SCIENCES; NATURVETENSKAP; Applied Environmental Science; tillämpad miljövetenskap;

   Sammanfattning : The overall objectives of this dissertation were to gain further understanding of the two following environmentally significant issues: (i) Determination of natural steroid hormones in blood plasma from perch (Perca fluviatilis) during a reproductive cycle and to evaluate the possibility of using the steroid composition as a biomarker for early signs of endocrine disruptive effects. (ii) Determination of dissolved free amino acids in size resolved airborne particles collected over the Arctic pack ice area (>80°N) in summer and to study their overall relationship with the ocean surface microlayer as a potential source. LÄS MER

3. 22. 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

4. 23. Factors influencing emission fluxes and bacterial enrichment in sea spray aerosols : Insights from laboratory and field studies

   Författare :Julika Zinke; Matthew E. Salter; Paul Zieger; Rachel A. Foster; E. Douglas Nilsson; Patricia K. Quinn; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Sea spray aerosols; eddy covariance fluxes; air-sea-exchange; bacteria; primary biological airborne particles; laboratory studies; field studies; Baltic Sea; North-Eastern Atlantic; Environmental Sciences; miljövetenskap;

   Sammanfattning : Sea spray aerosol (SSA) is one of the major natural aerosol sources and is produced when wave breaking entrains air into ocean surface water, which subsequently breaks up into bubbles. These bubbles rise to the surface and can scavenge biogenic material. LÄS MER

5. 24. Primary Marine Aerosol : Validation of sea spray source functions using observations and transport modeling

   Författare :Henrik Grythe; Johan Ström; Krejci Radovan; Bo Gustafsson; Lars Ahlm; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; marine aerosol; Applied Environmental Science; tillämpad miljövetenskap;

   Sammanfattning : Sea spray aerosols (SSA) are an important part of the climate system through their effects on the global radiative budget, both directly as scatterers and absorbers of solar and terrestrial radiation, and indirectly as cloud condensation nuclei (CCN) influencing cloud formation, lifetime and precipitation. In terms of their global mass, SSA is the largest source and has the largest uncertainty of all aerosols. LÄS MER

7. 25. The high Arctic summer aerosol : Size, chemical composition, morphology and evolution over the pack-ice

   Författare :Evelyne Hamacher-Barth; Caroline Leck; Stephan Weinbruch; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Arctic; aerosol; marine gel; electron microscopy; EDX-spectroscopy; chemical composition; morphology; size distribution; atmosfärvetenskap och oceanografi; Atmospheric Sciences and Oceanography;

   Sammanfattning : Aerosol particles, especially in the high Arctic are still not very well represented in climate models. Particle size and number concentrations are strongly under-predicted and temporal variations of aerosol composition and size are still not very well understood, mainly due to the sparsity of observations. LÄS MER