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Estimation of Offshore Wind Resources in Coastal Waters off Shirahama Using ENVISAT ASAR Images
National Institute of Advanced Industrial Science and Technology, 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568, Japan
Graduate School of Maritime Science, Kobe University, 5-1-1 Hukaeminamimachi, Higashinadaku, Kobe, Hyogo 658-0022, Japan
Institute of Technology and Science, Tokushima University, 2-1 Minamijyousanjima-cho, Tokushima, Tokushima 770-8506, Japan
Shirahama Oceanographic Observatory, Disaster Prevention Research Institute, Kyoto University, 2347-6 Katata, Shirahama, Nishimuro, Wakayama 649-2201, Japan
Marine Information Field, Port and Airport Research Institute, 3-1-1, Nagase, Yokosuka, Kanagawa 239-0826, Japan
* Author to whom correspondence should be addressed.
Received: 6 April 2013; in revised form: 28 May 2013 / Accepted: 29 May 2013 / Published: 6 June 2013
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.
Keywords: offshore wind resource assessment; synthetic aperture radar; ENVISAT； Japanese coastal waters; WRF
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MDPI and ACS Style
Takeyama, Y.; Ohsawa, T.; Yamashita, T.; Kozai, K.; Muto, Y.; Baba, Y.; Kawaguchi, K. Estimation of Offshore Wind Resources in Coastal Waters off Shirahama Using ENVISAT ASAR Images. Remote Sens. 2013, 5, 2883-2897.
Takeyama Y, Ohsawa T, Yamashita T, Kozai K, Muto Y, Baba Y, Kawaguchi K. Estimation of Offshore Wind Resources in Coastal Waters off Shirahama Using ENVISAT ASAR Images. Remote Sensing. 2013; 5(6):2883-2897.
Takeyama, Yuko; Ohsawa, Teruo; Yamashita, Tomohiro; Kozai, Katsutoshi; Muto, Yasunori; Baba, Yasuyuki; Kawaguchi, Koji. 2013. "Estimation of Offshore Wind Resources in Coastal Waters off Shirahama Using ENVISAT ASAR Images." Remote Sens. 5, no. 6: 2883-2897.