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Dissertation zugänglich unter
URN: urn:nbn:de:gbv:18-51683
URL: http://ediss.sub.uni-hamburg.de/volltexte/2011/5168/


High Resolution Wind and Bathymetry Maps from Synthetic Aperture Radar to increase Ship Safety and ShipTraffic Monitoring from Space

Hochaufgelöste Wind- und Bathymetriekarten aus Radardaten mit synthetischer Apertur zur Verbesserung der Schiffssicherheit und Schiffsroutenplanung   

Brusch, Stephan

pdf-Format:
 Dokument 1.pdf (6.838 KB) 


SWD-Schlagwörter: Radarfernerkundung , Satellitenfernerkundung , Ozeanographie, Bathymetrie , Schiffsdetektion , TerraSAR-X
Freie Schlagwörter (Deutsch): Wind , Seegang , Radar
Basisklassifikation: 38.90
Institut: Geowissenschaften
DDC-Sachgruppe: Geowissenschaften
Dokumentart: Dissertation
Hauptberichter: Graßl, Hartmut (Prof. Dr.)
Sprache: Englisch
Tag der mündlichen Prüfung: 02.02.2011
Erstellungsjahr: 2011
Publikationsdatum: 05.07.2011
Kurzfassung auf Englisch: In this work satellite images taken by space borne sensors are used to
explain atmospheric as well as oceanographic features, e.g. wind fields or ocean
wave heights, all are compared to operational numerical model output. One
focus in the first paper was to understand the synergy of high resolution passive
microwave satellite sensors and optical sensors on different space scales. The
jointly retrieved meteorological and oceanographical parameters, e.g. wind
speed and significant wave height, show the high quality of space based data in
understanding of complex systems, e. g. wave fields. A space based Radar and
imaging spectrometers are used to analyse wind and waves during extreme
weather conditions, in particular, to describe the spatial evolution of the
atmospheric boundary layer processes involved in cold air outbreaks. The
behaviour of wind fields in coastal and offshore regions is investigated and
compared to numerical model results. For wind field retrieval a geophysical
model function is used. High resolution radar satellites provide a fine scale
structure of wind fields and information on small-scale atmospheric features as
well as more extreme values of environmental parameters during high impact
2
weather, which are not captured well by the numerical models. One case study
showed that cloud patterns seen in the optical data and radar cross-section
modulation give a consistent dynamical picture of the atmospheric processes.
The relevance of space based data for assimilation into numerical models and
for offshore wind farming is discussed.
Waves are the most obvious feature in Synthetic Aperture Radar (SAR)
images over the ocean. The modulation of sea surface roughness by wind makes
them visible in radar images and thus variations of wave fields can be detected.
Due to the high horizontal resolution of SAR data (down to 1m) wave refraction
and shoaling of swell can be monitored. Radar sensors are able to monitor waves
with a wavelength longer then the cut-off wavelength. The cut-off wavelength
depends on the SAR sensor (resolution) and is a function of wind speed and
significant wave height. In this work algorithm to retrieve sea state parameters
measured by high resolution SAR data have been adapted from known C-Band
SAR systems (ERS-2/ENVISAT) to the new X-Band satellite TS-X (TerraSARX).
TS-X gives access to spatial resolution as fine as 1 m in Spotlight mode
and high resolution variability of coastal wave fields. Images from the TS-X
satellite are particularly suitable for the observation of wave behaviour in
transient and shallow water (<100m water depth). By computing the 2
dimensional spectra waves can be tracked. In the second paper it is shown, how
wave Refraction and shoaling can be monitored and the calculation of bottom
topography can be provided. The retrieved bathymetry is compared to ETOPO1
(a 1 arc-minute global relief model of Earth's surface that integrates land
topography and ocean bathymetry, source: NOAA), US Coastal Relief Model (a
3 arc-second US model integrating offshore bathymetry with land topography,
source: NOAA) and sea charts from the British Admiralty.
Knowledge of the water depth is one important parameter for monitoring
of ship traffic and secure navigation. Planning of ship routes is an important
economic factor. The knowledge about bathymetry in coastal regions or river
estuaries is of high interest. Therefore, ship detection and maritime surveillance
with high resolution sensors has increased, in particular in the field of maritime
security and maritime safety in the last years.
In the third paper first results on the combined use of TS-X ship
detection, AIS (Automatic Identification System), and Satellite AIS is presented.
The AIS system is an effective terrestrial method for tracking vessels in real
time typically up to 40 km off the coast. The quality of TS-X images with
respect to ship detection is evaluated and a first assessment of its performance
for ship detection is given. Velocity of a moving ship is estimated using
complex TS-X data. First results on simultaneous superposition of satellite AIS
and high resolution radar images are presented.

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