Abstract
Offshore wind resource maps for the coastal waters off Shirahama, Japan were made based on 104 images of the Advanced Synthetic Aperture Radar (ASAR) onboard the ENVISAT satellite. Wind speed fields were derived from the SAR images with the geophysical model function CMOD5.N. Mean wind speed and energy density were estimated using the Weibull distribution function. These accuracies were examined in comparison with in situ measurements from the Shirahama offshore platform and the Southwest Wakayama buoy (SW-buoy). Firstly, it was found that the SAR-derived 10 m-height wind speed had a bias of 0.52 m/s and a RMSE of 2.33 m/s at Shirahama. Secondly, it was found that the mean wind speeds estimated from SAR images and the Weibull distribution function were overestimated at both sites. The ratio between SAR-derived and in situ measured mean wind speeds at Shirahama is 1.07, and this value was used for a long-term bias correction in the SAR-derived wind speed. Finally, mean wind speed and wind energy density maps at 80 m height were made based on the corrected SAR-derived 10 m-height wind speeds and the ratio U80/U10 calculated from the mesoscale meteorological model WRF.
Highlights
From the satellite-borne Synthetic Aperture Radar (SAR) it is possible to retrieve a sea surface wind speed field with a high spatial resolution of tens to hundreds of meters, and it is expected that the SAR image can be used for wind resource assessment in coastal waters
This area is located in the western part of Japan, including the Kii Channel facing the Pacific Ocean, and known as a relatively windy coastal area in this region, because this channel gives passage to the northwesterly winter monsoon wind
(33°42'32''N, 135°19'58''E) is the oceanographic and meteorological observation station operated by the Disaster Prevention Research Institute, Kyoto University since 1994
Summary
From the satellite-borne Synthetic Aperture Radar (SAR) it is possible to retrieve a sea surface wind speed field with a high spatial resolution of tens to hundreds of meters, and it is expected that the SAR image can be used for wind resource assessment in coastal waters. The offshore wind resource assessment using SAR has been conducted in many places, especially in Europe (e.g., [1,2,3]). In Japan, since there has been little need for offshore wind resource assessment at least up to the accident of the Fukushima nuclear power plant, there are few papers in which offshore wind resource is practically assessed with SAR, except some preliminary papers like Kozai et al [4]. Offshore wind energy is gradually regarded as a promising electric power resource, and there is increased need for assessing the offshore wind resource. It is desirable that the SAR-based offshore wind resource assessment, which is reported to work well in European seas, could be applicable to Japanese coastal waters. The authors have found that the performance and accuracy of the SAR-based wind speed estimation method are different between
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
