Spaceborne synthetic aperture radar(SAR)can provide unique capabilities to measure ocean surface winds under tropical cyclones(TCs),on synoptic scales,and at a very high spatial resolution.In this paper,we first discu...Spaceborne synthetic aperture radar(SAR)can provide unique capabilities to measure ocean surface winds under tropical cyclones(TCs),on synoptic scales,and at a very high spatial resolution.In this paper,we first discuss the accuracy and reliability of SAR-retrieved TC marine winds.The results show that wind retrievals from SAR images are in good agreement with Stepped Frequency Microwave Radiometer(SFMR)measurements,with root-mean-square error(RMSE)and correlation coefficient(CC)of 3.52 m s^(−1) and 0.91,respectively.Based on the marine winds retrieved from SAR images,a relatively simple method is applied to extract the storm intensity(maximum wind speed)and wind radii(R34,R50,and R64)from 234 cross-polarized SAR images,in the Northwest Pacific Ocean from 2015 to 2023.The SAR-retrieved TC wind radii and intensities are compared with the best-track reports,with RMSEs for R34,R50,and R64 being 48.32,41.88,and 38.51 km,and CCs being 0.87,0.83,and 0.65,respectively.In terms of TC intensity,the RMSE and bias between SAR estimates and best-track data are 7.32 and 0.38 m s^(−1),respectively.For TC Surigae(2023),we found that employing a combination of multiplatform SARs,acquired within a short time interval,has the potential to simultaneously measure the intensity and wind structure parameters.In addition,for a storm with a long life cycle,the multitemporal synergistic SARs can be used to investigate fine-scale features of the TC ocean winds,as well as the evolution of TC surface wind intensities and wind structures.展开更多
该文对SAR反演邻近岸海面风场的有关问题进行了深入研究。首先提出了邻近岸海面风向估计方法,在最小距离准则下利用邻近海域的风向估计所需的邻近岸海面风向。然后给出了使用ENVISAT/ASAR的IM成像模式PRI数据反演邻近岸海面风速的方法,...该文对SAR反演邻近岸海面风场的有关问题进行了深入研究。首先提出了邻近岸海面风向估计方法,在最小距离准则下利用邻近海域的风向估计所需的邻近岸海面风向。然后给出了使用ENVISAT/ASAR的IM成像模式PRI数据反演邻近岸海面风速的方法,比较了地球物理模型函数(Geophysical Model Function,GMF)模型性能,提出了海面风速分段反演算法。它们组成了完整的SAR反演邻近岸海面风场方法。通过实验、比较,验证了上述方法的有效性和合理性。展开更多
基金Supported by the National Natural Science Foundation of China(42305153)Zhejiang Provincial Natural Science Foundation of China(LQ21D060001 and LZJMZ23D05000)+6 种基金East China Meteorological Science and Technology Collaborative Innovation Foundation Cooperation Project(QYHZ202307)Fengyun Application Pioneering Project(FY-APP-2021.0105)Science and Technology Project of Zhejiang Meteorological Bureau(2021YB07,2022ZD06,and 2023YB06)Open Project of Key Laboratory of Meteorological Disaster,Ministry of Education/Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters(KLME202408)Open Grants of the State Key Laboratory of Severe Weather(2024LASW-B22)Innovation and Development Project of China Meteorological Administration(CXFZ2022J040)Youth Innovation Team Fund of China Meteorological Administration(CMA2023QN12)。
文摘Spaceborne synthetic aperture radar(SAR)can provide unique capabilities to measure ocean surface winds under tropical cyclones(TCs),on synoptic scales,and at a very high spatial resolution.In this paper,we first discuss the accuracy and reliability of SAR-retrieved TC marine winds.The results show that wind retrievals from SAR images are in good agreement with Stepped Frequency Microwave Radiometer(SFMR)measurements,with root-mean-square error(RMSE)and correlation coefficient(CC)of 3.52 m s^(−1) and 0.91,respectively.Based on the marine winds retrieved from SAR images,a relatively simple method is applied to extract the storm intensity(maximum wind speed)and wind radii(R34,R50,and R64)from 234 cross-polarized SAR images,in the Northwest Pacific Ocean from 2015 to 2023.The SAR-retrieved TC wind radii and intensities are compared with the best-track reports,with RMSEs for R34,R50,and R64 being 48.32,41.88,and 38.51 km,and CCs being 0.87,0.83,and 0.65,respectively.In terms of TC intensity,the RMSE and bias between SAR estimates and best-track data are 7.32 and 0.38 m s^(−1),respectively.For TC Surigae(2023),we found that employing a combination of multiplatform SARs,acquired within a short time interval,has the potential to simultaneously measure the intensity and wind structure parameters.In addition,for a storm with a long life cycle,the multitemporal synergistic SARs can be used to investigate fine-scale features of the TC ocean winds,as well as the evolution of TC surface wind intensities and wind structures.
文摘该文对SAR反演邻近岸海面风场的有关问题进行了深入研究。首先提出了邻近岸海面风向估计方法,在最小距离准则下利用邻近海域的风向估计所需的邻近岸海面风向。然后给出了使用ENVISAT/ASAR的IM成像模式PRI数据反演邻近岸海面风速的方法,比较了地球物理模型函数(Geophysical Model Function,GMF)模型性能,提出了海面风速分段反演算法。它们组成了完整的SAR反演邻近岸海面风场方法。通过实验、比较,验证了上述方法的有效性和合理性。
