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Visar resultat 1 - 5 av 12 avhandlingar som matchar ovanstående sökkriterier.

1. 1. Studies of planetary waves in ozone and temperature fields as observed by the Odin satellite in 2002-2007

   Författare :Alla Belova; Sheila Kirkwood; Andrew Klekociuk; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; middle atmosphere dynamics; planetary waves; 5-day planetary wave; temperature-ozone relationship; Odin satellite; Atmosphere and hydrosphere sciences; Atmosfärs- och hydrosfärsvetenskap;

   Sammanfattning : The results presented in this PhD thesis are mainly based on measurements collected by the advanced sub-mm radiometer (SMR) aboard the Odin satellite in 2002-2007. The primary data are series of temperature and ozone profiles in the middle atmosphere up to 68 km. LÄS MER

3. 2. Investigation of Polar Mesosphere Summer Echoes in Northern Scandinavia

   Författare :Victoria Barabash; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Physics; Polar Mesosphere Summer Echoes; middle atmospheric dynamics; ionospheric disturbances; solar radiation; aerosol; MST radar; planetary waves; noctilucent clouds; Fysik; Physics; Fysik; rymdfysik; Space Physics;

   Sammanfattning : This PhD thesis deals with phenomena which are closely related to the unique thermal structure of the polar summer mesosphere, namely Polar Mesosphere Summer Echoes (PMSE). PMSE are strong radar echoes commonly observed by VHF MST radars from thin layers in the 80-90 km altitude interval at high latitudes during summer. LÄS MER

4. 3. On the interaction between ice sheets and the large-scale atmospheric circulation over the last glacial cycle

   Författare :Marcus Löfverström; Rodrigo Caballero; Johan Nilsson; David Battisti; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Atmospheric stationary waves; coupled atmosphere-ice sheet modelling; stationary wave-ice sheet interactions; atmosfärvetenskap och oceanografi; Atmospheric Sciences and Oceanography;

   Sammanfattning : The last glacial cycle (c. 115-12 kyr BP) was the most recent in a series of recurring glaciations of the subpolar continents. Massive ice sheets evolved in Eurasia and North America, which, at their maximum, were of continental scale and together lowered the global sea-level by approximately 100 m. LÄS MER

5. 4. Large Eddy Simulation of Non-Local Turbulence and Integral Measures of Atmospheric Boundary Layers

   Författare :Igor Esau; Frans Nieuwstadt; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Meteorology; Planetary boundary layers; large eddy simulations; non-local turbulence; Meteorologi; Meteorology; Meteorologi; Meteorology; meteorologi;

   Sammanfattning : A new large eddy simulation (LES) code is developed and used to investigate non-local features of turbulent planetary boundary layers (PBLs). The LES code is based on filtered Navier-Stokes equations, which describe motions of incompressible, Boussinesq fluid at high Reynolds numbers. LÄS MER

7. 5. The Klimontovich description of complex plasma systems : Low frequency electrostatic modes, spectral densities of fluctuations and collision integrals

   Författare :Panagiotis Tolias; Lars Blomberg; Carmine Castaldo; KTH; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; complex plasmas; dusty plasmas; Klimontovich equations; kinetic theory; dust acoustic waves; collision integrals;

   Sammanfattning : Plasmas seeded with solid particulates of nanometer to micron sizes (complex plasma systems) are a ubiquitous feature of intergalactic, interstellar and planetary environments but also of plasma processing applications or even fusion devices. Their novel aspects compared with ideal multi-component plasmas stem from (i) the large number of elementary charges residing on the grain surface, (ii) the variability of the charge over mass ratio of the dust component, (iii) the inherent openness and dissipative nature of such systems. LÄS MER