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A Marine Radar Wind Sensor

Dankert, Heiko and Horstmann, Jochen (2007) A Marine Radar Wind Sensor. Journal of Atmospheric and Oceanic Technology, 24 (9). pp. 1629-1642. ISSN 0739-0572. http://resolver.caltech.edu/CaltechAUTHORS:DANjaot07

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Abstract

A new method for retrieving the wind vector from radar-image sequences is presented. This method, called WiRAR, uses a marine X-band radar to analyze the backscatter of the ocean surface in space and time with respect to surface winds. Wind direction is found using wind-induced streaks, which are very well aligned with the mean surface wind direction and have a typical spacing above 50 m. Wind speeds are derived using a neural network by parameterizing the relationship between the wind vector and the normalized radar cross section (NRCS). To improve performance, it is also considered how the NRCS depends on sea state and atmospheric parameters such as air–sea temperature and humidity. Since the signal-to-noise ratio in the radar sequences is directly related to the significant wave height, this ratio is used to obtain sea state parameters. All radar datasets were acquired in the German Bight of the North Sea from the research platform FINO-I, which provides environmental data such as wind measurements at different heights, sea state, air–sea temperatures, humidity, and other meteorological and oceanographic parameters. The radar-image sequences were recorded by a marine X-band radar installed aboard FINO-I, which operates at grazing incidence and horizontal polarization in transmit and receive. For validation WiRAR is applied to the radar data and compared to the in situ wind measurements from FINO-I. The comparison of wind directions resulted in a correlation coefficient of 0.99 with a standard deviation of 12.8°, and that of wind speeds resulted in a correlation coefficient of 0.99 with a standard deviation of 0.41 m s^−1. In contrast to traditional offshore wind sensors, the retrieval of the wind vector from the NRCS of the ocean surface makes the system independent of the sensors’ motion and installation height as well as the effects due to platform-induced turbulence.


Item Type:Article
Additional Information:© 2007 American Meteorological Society. (Manuscript received 10 May 2006, in final form 8 November 2006) All radar-image sequences were kindly made available by the company Ocean-Waves (Lüneburg, Germany). The in situ data were kindly provided by the Bundesamt für Seeschifffahrt und Hydrographie (BSH) (Hamburg, Germany).
Record Number:CaltechAUTHORS:DANjaot07
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:DANjaot07
Alternative URL:http://dx.doi.org/10.1175/JTECH2083.1
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:9086
Collection:CaltechAUTHORS
Deposited By: Archive Administrator
Deposited On:26 Oct 2007
Last Modified:26 Dec 2012 09:45

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