Sökning: "surface winds"

Visar resultat 1 - 5 av 35 avhandlingar innehållade orden surface winds.

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. Numerical Simulations of Flows around Trains and Buses in Cross Winds

   Författare :Hassan Hemida; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; winds; Trains and buses aerodynamics; LES; DES;

   Sammanfattning : When cruising in strong winds, ground vehicles can experience strong aerodynamic forces and moments that may increase drag, reduce their stability, generate noise and induce accidents in the case of strong side winds. However, prevention of the unwanted influences of side winds requires that the flow structures around vehicles are fully understood in both the instantaneous and time-averaged flow. LÄS MER

5. 4. Space-Time Prediction of Ocean Winds

   Författare :Anders Malmberg; Matematisk statistik; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Statistics; operations research; image warping; thin-plate splines.; near-surface ocean winds; variogram parameters; Space-time Kalman filtering; real-time assimilation; residual wind speed; actuarial mathematics; programming; Statistik; operationsanalys; programmering; aktuariematematik;

   Sammanfattning : The topic of this thesis is inspired by an experiment in which a vessel, laying a submarine cable, was provided with forecasts overlaid with satellite observations of significant wave height. During the operation, the vessel was close to an adverse weather area and the personnel on board could confirm that the forecast was not as close to the "ground truth" as the satellite observation was. LÄS MER

7. 5. Changes in near-surface winds across Sweden over the past decades - Observations and simulations

   Författare :Lorenzo Minola; Göteborgs universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; mean and gust wind speed; stilling-reversal phenomena; regional climate models; climate reanalyses; ERA5; parametrization; NAO; extratropical cyclones; surface roughness; Sweden;

   Sammanfattning : Driven by a combination of anthropogenic activities and climate changes, near- surface terrestrial winds displayed a large decrease in their magnitude in the past decades, named “stilling”, and a recent recovery in their slowdown. Understanding how wind has changed and identifying the factors behind the observed variabilities is crucial so that reasonable future wind scenarios can be constructed. LÄS MER