Investigation of accidents in severe weather events using satellite radar data
Susanne Lehner(1) , Wolfgang Rosenthal(2) , Johannes Schulz-Stellenfleth(1) , and Thomas König(1)
German Aerospace Center,
D 82234 Wessling,
(2) Institute for Coastal Research, Max Planck Str 1, D 2105 Geesthacht, Germany
Traditionally, rogue waves and wave groups have been studied by means of time series analysis of buoy records, which provides information about the temporal variability of such phenomena at a fixed ocean position. Radar systems instead provide spatial information on the sea surface topography. The synthetic aperture radar (SAR) yields high resolution two dimensional images of the radar backscatter properties of the sea surface and is thus be used to measure wind fields and sea state from space.
In this pare wind fields and ocean wave fields around offshore platforms are analysed. Extreme wave phenomena are investigated using SAR intensity maps. This includes the detection of those rogue waves, and extreme wave groups, as well as the investigation on wave statistics with respect to those extreme wave events.
Special emphasis is given to cases in which accidents happened at the platforms. Examples of SAR derived wave fields are given for the offshore oil platforms Ekofisk and Draupner situated in the North Sea and the new measurement platform FINO at which time series of wind speed and wave height are acquired to prepare for an offshore wind farm.
In addition several ship accidents that happened in 1999 and 2000 during which reprocessed wave mode data are available are going to be investigated.
Discussion and Response Note
(received 4/5/2006) by W. Rosenthal, S. Lehner, J. Schulz-Stellenfleth,
with reference to the SEASAR paper
Why SAR wave mode data of ERS and Envisat are inadequate for giving the probability of occurrence of freak waves by Peter Janssen and Werner Alpers.