The purpose is to study the accuracy of ocean wave parameters retrieved from C-band VV-polarization Sentinel-1Synthetic Aperture Radar（SAR） images, including both significant wave height（SWH） and mean wave period...The purpose is to study the accuracy of ocean wave parameters retrieved from C-band VV-polarization Sentinel-1Synthetic Aperture Radar（SAR） images, including both significant wave height（SWH） and mean wave period（MWP）, which are both calculated from a SAR-derived wave spectrum. The wind direction from in situ buoys is used and then the wind speed is retrieved by using a new C-band geophysical model function（GMF） model,denoted as C-SARMOD. Continuously, an algorithm parameterized first-guess spectra method（PFSM） is employed to retrieve the SWH and the MWP by using the SAR-derived wind speed. Forty-five VV-polarization Sentinel-1 SAR images are collected, which cover the in situ buoys around US coastal waters. A total of 52 subscenes are selected from those images. The retrieval results are compared with the measurements from in situ buoys. The comparison performs good for a wind retrieval, showing a 1.6 m/s standard deviation（STD） of the wind speed, while a 0.54 m STD of the SWH and a 2.14 s STD of the MWP are exhibited with an acceptable error.Additional 50 images taken in China＇s seas were also implemented by using the algorithm PFSM, showing a 0.67 m STD of the SWH and a 2.21 s STD of the MWP compared with European Centre for Medium-range Weather Forecasts（ECMWF） reanalysis grids wave data. The results indicate that the algorithm PFSM works for the wave retrieval from VV-polarization Sentinel-1 SAR image through SAR-derived wind speed by using the new GMF C-SARMOD.展开更多
The propagation of waves in shallow waters is affected by the bottom topography unlike deep water waves of the coastal environment.Due to the interaction of the wave with bed topography,the wave transformation process...The propagation of waves in shallow waters is affected by the bottom topography unlike deep water waves of the coastal environment.Due to the interaction of the wave with bed topography,the wave transformation processes occur.Refraction,diffraction,shoaling,and breaking are the wave transforma-tion processes that occur in the coastal environment.The significant wave height over rugged topography is a standardized statistics to denote the characteristic height of the random waves in a sea state.There-fore,the objective of the present study is to predict the significant wave height over rugged topography.The SWAN standalone and SWAN DHH platform are used to predict significant wave height over rugged topography in Mehamn harbour,Norway.The SWAN model results are almost similar to the lab data of Vold and Lothe(2009)for all the 22 scenarios at all the output locations.Further,the four cases reported by Taehun(2011)and lab data from Vold and Lothe(2009)for that four cases are compared with the SWAN model results.It is observed that the SWAN model results are much closer to the lab data of Vold and Lothe(2009).展开更多
基金The Public Welfare Technical Applied Research Project of Zhejiang Province of China under contract No.2015C31021the National Key Research and Development Program of China under contract No.2016YFC1401605the Scientific Foundation of Zhejiang Ocean University of China
文摘The purpose is to study the accuracy of ocean wave parameters retrieved from C-band VV-polarization Sentinel-1Synthetic Aperture Radar（SAR） images, including both significant wave height（SWH） and mean wave period（MWP）, which are both calculated from a SAR-derived wave spectrum. The wind direction from in situ buoys is used and then the wind speed is retrieved by using a new C-band geophysical model function（GMF） model,denoted as C-SARMOD. Continuously, an algorithm parameterized first-guess spectra method（PFSM） is employed to retrieve the SWH and the MWP by using the SAR-derived wind speed. Forty-five VV-polarization Sentinel-1 SAR images are collected, which cover the in situ buoys around US coastal waters. A total of 52 subscenes are selected from those images. The retrieval results are compared with the measurements from in situ buoys. The comparison performs good for a wind retrieval, showing a 1.6 m/s standard deviation（STD） of the wind speed, while a 0.54 m STD of the SWH and a 2.14 s STD of the MWP are exhibited with an acceptable error.Additional 50 images taken in China＇s seas were also implemented by using the algorithm PFSM, showing a 0.67 m STD of the SWH and a 2.21 s STD of the MWP compared with European Centre for Medium-range Weather Forecasts（ECMWF） reanalysis grids wave data. The results indicate that the algorithm PFSM works for the wave retrieval from VV-polarization Sentinel-1 SAR image through SAR-derived wind speed by using the new GMF C-SARMOD.
文摘The propagation of waves in shallow waters is affected by the bottom topography unlike deep water waves of the coastal environment.Due to the interaction of the wave with bed topography,the wave transformation processes occur.Refraction,diffraction,shoaling,and breaking are the wave transforma-tion processes that occur in the coastal environment.The significant wave height over rugged topography is a standardized statistics to denote the characteristic height of the random waves in a sea state.There-fore,the objective of the present study is to predict the significant wave height over rugged topography.The SWAN standalone and SWAN DHH platform are used to predict significant wave height over rugged topography in Mehamn harbour,Norway.The SWAN model results are almost similar to the lab data of Vold and Lothe(2009)for all the 22 scenarios at all the output locations.Further,the four cases reported by Taehun(2011)and lab data from Vold and Lothe(2009)for that four cases are compared with the SWAN model results.It is observed that the SWAN model results are much closer to the lab data of Vold and Lothe(2009).
