Posters
Come meet the poster presenters to ask them questions and discuss their work
We would like to invite you to come and see the posters at our upcoming conference. The posters will showcase a diverse range of research topics and provide an opportunity for delegates to engage with the authors and learn more about their work. Whether you are a seasoned researcher or simply curious about the latest developments in your field, we believe that the posters will offer something of interest to everyone. So please, join us at the conference and take advantage of this opportunity to learn and engage with your peers in the academic community. We look forward to seeing you there!
PO152: Possibilities of utilization of ASNARO-2 X-band SAR for offshore wind retrieval
Yuko Takeyama, Associate Professor, Tokyo University of Marine Science and Technology
Abstract
Offshore wind resource assessment has been performed based on wind information obtained from some methods like in situ measurements and numerical simulations. Satellite remote sensing with microwaves is also one of the most effective methods. Synthetic aperture radar (SAR) onboard sun-synchronous, near-polar orbit satellites have been utilized for decades for offshore wind resource assessment. A X-band (8 to 12 GHz) SAR onboard ASNARO-2 have been operated since 2018. X-band Geophysical Model Functions (GMFs) for TerraSAR-X and Cosmo-SkyMed had already been developed to retrieve the sea surface wind speed. Now a new GMF is necessary to utilized ASNARO-2 images for offshore wind retrievals, and these possibilities should be evaluated. This study is intended as a revealing relationship between normalized radar cross section (NRCS), which indicates a microwave strength scattered from the sea surface, radar incidence angle, wind speed to develop the new GMF. Moreover, an accuracy of the retrieved wind speed with the GMF from ASNARO-2 is clarified. NRCSs from ASNARO-2 ScanSAR mode images are compared with local forecast model (LFM) wind vectors for each radar incidence angle. The NRCS is decreasing when the incidence angle is increasing. The NRCS is also decreasing when the LFM wind speed is decreasing. These characteristics are similar to NRCSs observed from another SARs. It means that a basic formular of GMFs for another SARs could be used for ASNARO-2. Utilizing the new GMF, which is based on a basic formular from previous studies, it is found that the NRCS can be calculated from the LFM wind speed with a root mean square error (RMSE) of 1.14 dB, and inversely the wind speed can be retrieved from ASNARO-2 images with a RMSE of 1.37 m/s and a bias of -0.10 m/s.
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