Coupling between the ionized and neutral atmosphere through particle collisions allows an indirect study of the neutral atmosphere through measurements of ionospheric plasma parameters. We estimate the neutral density of the upper thermosphere above ~250 km with the European Incoherent Scatter Svalbard Radar (ESR) using the year-long operations of the International Polar Year from March 2007 to ...

Avalanches usually occur in steep, snow-covered mountain sides under special conditions. The stability of the snowpack depends, among other things, on the melting and freezing of the snowpack. If a snow covered area has not undergone a melt/freeze-process, it could potentially be unstable due to depth hoar or buried layers of frost, and therefore pose an avalanche risk if the area is located at a ...

We study the conditions within, and dynamics of fragmented mesospheric dust particles inside, the Faraday-cup type dust probe MUDD using numerical simulations with a dedicated model. The transport of singly charged fragments from impacting NLC particles on the main grid in MUDD, have been calculated on the basis of supplementary models of the neutral gas conditions and electric field structure within ...

Larval stages are among those most vulnerable to ocean acidification (OA). Projected atmospheric CO2 levels for the end of this century may lead to negative impacts on communities dominated by calcifying taxa with planktonic life stages. We exposed Mediterranean mussel (Mytilus galloprovincialis) sperm and early life stages to pHT levels of 8.0 (current pH) and 7.6 (2100 level) by manipulating pCO2 ...

Radio frequency interference (RFI) is a known issue in low-frequency radar remote sensing. In synthetic aperture radar (SAR) image processing, RFI can cause severe degradation of image quality, distortion of polarimetric signatures, and an increase of the SAR phase noise level. To address this issue, a processing system was developed that is capable of reliably detecting, characterizing, and mitigating ...

A statistical model for multilook polarimetric radar data is presented where the polarimetric channels are associated with individual texture variables having potentially different statistical properties. The feasibility of producing closed form probability density functions under certain restrictions is outlined. Mellin kind statistics are derived under various assumptions on the texture variables, ...

The evanescent field of an optical waveguide can be used to trap and propel microscopic particles. A 1µm particle is trapped on a strip waveguide and propelled forward until it reaches a 10µm gap at the centre of a loop, created by splitting the waveguide into two branches. According to simulations, the particle will be elevated 3µm in the gap and be stably trapped in the middle of the gap. The goal ...

With rising energy demands as well as technological advances, offshore wind power production is becoming an attractive option. However, it is necessary to estimate the wind climate at potential sites in order to achieve optimal siting, and numerical weather prediction models as well as satellite SAR can been used in a first evaluation for this purpose. This study looked the how ASAR and model wind ...

PI-film, also known as Kapton, is a widely used polymer in the production of electronic equipment. Its use in printed circuit boards and sensors is increasing. It is therefore important to have knowledge about ultrasonic attenuation in the polymer. The main goal of this thesis was to investigate the attenuation of ultrasound through different polymers with different thicknesses. The presentation ...

This thesis present a self-consistent derivation of reduced fluid models for geophysical dynamics confined to the midlatitude region. The reduced model will be derived by use of a regular perturbation method, that gives the same result as the classical models, such as the barotropic and baroclinic quasi-gestrophic potential vorticity model. It will be shown that such a rigorous treatment self-consistently ...