Sökning: "surface currents"

Visar resultat 1 - 5 av 109 avhandlingar innehållade orden surface currents.

  1. 1. Retrieval of ocean surface winds and currents using satellite synthetic aperture radar and infrared radiometry

    Författare :Gisela Carvajal; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; surface currents; infrared radiometry; synthetic aperture radar; surface winds; maximum cross correlation; wind direction;

    Sammanfattning : This thesis focuses on the development, analysis and evaluation of methods for the retrieval of ocean surface winds with synthetic aperture radar (SAR) and surface currents with infrared (IR) radiometer sensors. The SAR wind speed retrievals are based on geophysical model functions using wind directions obtained with two approaches. LÄS MER

  3. 2. Retrieval of Ocean Surface Currents and Winds Using Satellite SAR backscatter and Doppler frequency shift

    Författare :Anis Elyouncha; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Doppler centroid analysis; Bayesian inversion; ocean surface winds; Ocean surface currents; synthetic aperture radar; along-track InSAR;

    Sammanfattning : Ocean surface winds and currents play an important role for weather, climate, marine life, ship navigation, oil spill drift and search and rescue. In-situ observations of the ocean are sparse and costly. Satellites provide a useful complement to these observations. LÄS MER

  4. 3. Electrical Charges on Polymeric Insulator Surfaces and their Impact on Flashover Performance

    Författare :Sarath Kumara; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; streamer criterion; polymeric insulation; flashover voltage; surface potential; bulk conductivity; surface conduction; humidity; bulk neutralization; charge decay; Surface charge; silicone rubber; corona charging; gas neutralization;

    Sammanfattning : Utilization of remotely located sustainable energy resources such as solar, wind and hydro calls for further developments of long-distance electric power transmissions operating at ultra-high voltage (UHV) levels which may exceed 1000 kV ac and 800 kV dc utilized today. It is foreseen that insulation of such transmission systems is to be based on polymeric materials that can provide a number of technical benefits over traditionally used glass and porcelain based insulation. LÄS MER

  5. 4. Numerical Model of Beach Topography Evolution due to Waves and Currents: Special Emphasis on Coastal Structures

    Författare :Thanh Nam Pham; Avdelningen för Teknisk vattenresurslära; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; morphodynamics; surface roller; wave-induced currents; random waves; sediment transport; coastal structures;

    Sammanfattning : The beach topography change in the nearshore zone may be induced by natural phenomena such as wind, wave, storm, tsunami, and sea level rise. However, it can also be caused by man-made structures and activities, for example, groins, detached breakwaters, seawalls, dredging, and beach nourishment. LÄS MER

  7. 5. Mode and Polarization Control in VCSELs using Surface Structures

    Författare :Åsa Haglund; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; single mode; dynamics; surface relief; Semiconductor laser; polarization; vertical-cavity surface-emitting laser; sub-wavelength grating; fabrication;

    Sammanfattning : The vertical-cavity surface-emitting laser (VCSEL) is a novel, low-cost light source with many attractive performance characteristics, such as low operating current, circular output beam, and high modulation bandwidth at low currents. This together with its easy integration into two-dimensional arrays has made it an established transmitter in short-distance single and parallel fiber-optical links, and new applications are continuously arising. LÄS MER