Sökning: "polar winter"

Visar resultat 1 - 5 av 27 avhandlingar innehållade orden polar winter.

  1. 1. Viral Loop Dynamics in Temperate and Polar Freshwaters

    Författare :Christin Säwström; Biologiska institutionen; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; akvatisk ekologi; aquatic ecology; marine biology; Hydrobiology; temperate; polar; freshwaters; nutrient limitation; bacterial mortality; lysogeny; dissolved organic carbon; humic; Arctic; Antarctic; Bacteria; Virus; limnology; Marinbiologi; limnologi;

    Sammanfattning : All cellular organisms in aquatic environments are susceptible to virus attack. Viruses are the smallest but most abundant biological entities in freshwaters. This thesis describes interactions between viruses and bacteria in temperate and polar freshwaters with particular emphasis on Arctic and Antarctic aquatic systems. LÄS MER

  3. 2. Observations of water vapour in the middle atmosphere

    Författare :Stefan Lossow; Jörg Gumbel; Jacek Stegman; Daniel R. Marsh; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; water vapour; mesosphere; stratosphere; dynamics; Odin satellite; limb sounding; microwave; tropics; polar winter; Meteorology; Meteorologi; meteorologi; Meteorology;

    Sammanfattning : Water vapour is the most important greenhouse gas and plays a fundamental role in the climate system and for the chemistry of the Earth's atmosphere. This thesis presents observations of water vapour in the middle atmosphere with a particular focus on the mesosphere. LÄS MER

  4. 3. Biogenic Halocarbons in Polar Sea Ice

    Författare :Anna Granfors; Göteborgs universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Volatile biogenic halocarbons; Sea ice; Antarctica; ice-air flux; gases;

    Sammanfattning : Sea ice is to date a rather poorly investigated part of the cycling of volatile halogenated organic compounds, halocarbons. These compounds are natural sources of reactive iodine and bromine to the atmosphere, and are produced in the marine environment. LÄS MER

  5. 4. Mesoscale processes in the polar atmosphere : radar remote sensing, balloon-borne in situ measurements and modelling

    Författare :Maria Mihalikova; Suzanne Gray; Luleå tekniska universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Rymdteknik; Space Technology;

    Sammanfattning : Mesoscale processes (atmospheric phenomena with horizontal scales ranging from a few tens to several hundred kilometres and lasting from a few tens of minutes to a few days) have the potential to influence the chemical composition of the troposphere. Tropopause folds and mountain waves are two important types of mesoscale processes. LÄS MER

  7. 5. Lidar Measurements of Polar Stratospheric Clouds in the Arctic

    Författare :Peggy Achtert; Farahnaz Khosrawi; Jörg Gumbel; Richard Collins; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; atmosfärvetenskap och oceanografi; Atmospheric Sciences and Oceanography;

    Sammanfattning : Polar Stratospheric Clouds (PSCs) play a key role for ozone depletion in the polar stratosphere. Its magnitude depends on the type of PSC and its lifetime and extent. This thesis presents PSC observations conducted with the Esrange lidar and the space-borne CALIPSO lidar.PSCs are separated into three types according to their optical properties. LÄS MER