| 摘要: |
| 欧洲环境卫星-高级合成孔径雷达（Environmental Satellite-Advanced Synthetic Aperture Radar，Envisat-ASAR）波模式数据提供了全球风、浪要素信息，在海浪模式预报与同化方面有重要作用。该数据合成孔径雷达（Synthetic Aperture Radar，SAR）图像普遍存在海浪条纹清晰度不同的现象，但是否影响数据精度尚无定论。本文通过比较2010年NODC （the National Oceanographic Date Center）浮标观测数据和波模式数据，发现经过官方修正后的海浪参数反而具有更大误差。进而通过对比不同条纹清晰度的SAR图像反演参数误差，揭示了ASAR产品海浪参数与浮标测量值之间的误差与海浪条纹清晰度的关系。结果表明：海浪条纹清晰的SAR图像的主波波长和主波周期的反演误差更小，而条纹不清晰SAR图像的有效波高和风速的反演误差更小。通过分析海浪参数对海浪条纹清晰度的敏感性，证实了有效波高和方位向截断波长对SAR图像条纹清晰度的响应最好，波陡次之，与卫星飞行方位角和入射角无关。因此，在反演和修正SAR波模式数据时，考虑图像的条纹清晰度，将会有效提高反演数据的精度。该研究可为高分三号等卫星的波模式数据波浪要素反演精度的提升提供有价值的参考。 |
| 关键词: Envisat-ASAR (Environmental Satellite-Advanced Synthetic Aperture Radar)波模式数据 NODC (the National Oceanographic Date Center)浮标 图像条纹清晰度 误差分析 |
| DOI：10.11693/hyhz20181100273 |
| 分类号:P71;TP722.6 |
| 基金项目:国家自然科学基金项目，41376010号。 |
附件 |
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| THE CORRELATION ANALYSIS BETWEEN IMAGES STRIPE DEFINITION AND INVERSION PARAMETERS ERROR IN ASAR WAVE MODE |
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CAO Chuan-Chuan, SUN Jian, ZHANG Wen-Qing
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College of Oceanic and Atmospheric Sciences, Ocean University of China, Qingdao 266100, China
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| Abstract: |
| Envisat-ASAR wave mode data provide wind and wave information in the world, and play an important role in model prediction and data assimilation. However, a common phenomenon is that SAR images have different stripes definitions. Whether the definition would affect the data accuracy remains uncertain. We compared the measurement of in-situ buoy and wave mode data of year 2010, and found that the wave parameters after the official correction could instead generate bigger errors. Therefore, we compared the parameters errors of SAR image inversion in different stripe definitions, analyzed the errors between the ASAR products and buoy measurements, and revealed the relationship between the errors and the wave stripe definition. The results show that SAR images with higher-definition wave stripes could generate smaller inversion error in the dominant wavelength and period, while those with lower-definition ones could do so in the significant wave height and wind speed. In addition, we analyzed the sensitivity from wave parameters to the definition of wave stripes, and confirmed that SWH and azimuth cutoff wavelength have the best response to the SAR image stripe definition, and wave steepness is the second, satellite flight direction angle and incident angle are independence of imaging definition. Therefore, it is necessary to consider the image definition when processing SAR wave mode data, which will improve the accuracy effectively. The study may provide a valuable reference to GF-3 and other satellite wave mode data. |
| Key words: Envisat-ASAR wave mode data NODC buoy SAR image stripe definition error analysis |
