| 摘要: |
| 为了验证波谱仪反演二维海浪谱的功能, 根据海浪波谱仪的信号形成机制, 总结了机载波谱仪反演海浪的流程。利用机载波谱仪回波数据, 通过自相关和互相关两种功率谱估计方法, 反演了二维海浪谱。最后通过与浮标测量的二维海浪谱进行对比, 验证了该机载波谱仪探测二维海浪谱的有效性。结果表明, 无论采用自相关函数还是互相关函数进行功率谱估计, 得到的主波波长和有效波高与实际二维海浪谱基本一致。互相关函数法得到的交叉谱能去除180°模糊现象, 其在计算有效波高时相对于自相关函数会稍微偏小。在计算斜率方差时可以采用5°～12°入射角范围的后向散射系数进行公式拟合, 因此定标与否并不影响最后的二维海浪谱结果, 未来星载波谱仪只有靠多波束联合才能实现。 |
| 关键词: 波谱仪 功率谱估计 二维海浪谱 180°模糊 |
| DOI：10.11759/hykx20151224004 |
| 分类号: |
| 基金项目:国家重点研发计划子课题(2016YFC1401005); 江苏省自然科学基金项目(BK2011008); 国家自然科学基金(41476158); 江苏省高等教育优势学科项目 |
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| Retrieval method of an ocean wave spectrum using an airborne spectrometer and performing the validation |
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LI Xiu-zhong,HE Yi-jun,MENG Jun-min,ZHANG Zhen-hua
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| Abstract: |
| The ocean wave retrieval method is designed on the basis of the signal formation principle of an ocean wave spectrometer. By using the spectra estimation methods via the auto-correlation and cross-correlation functions, the two-dimensional ocean wave spectrum is obtained. Finally, after comparing the spectrum received from the buoy and that retrieved from the spectrometer, the effectiveness of detecting a two-dimensional spectrum from an airborne spectrometer is evaluated. We observe that in the environment of flight, the results of the methods using the auto-correlation and cross-correlation functions for retrieving ocean wave spectrum are consistent with that obtained from the buoy. From the cross spectrum, the ambiguity of 180° is excluded, although the significant wave height is smaller than that from auto-correlation method. When the sea-slope variance is calculated, the radar backscattering coefficients of the incidence angles at 5°–12° are fitted. Therefore, calibration of the radar backscattering coefficients is not required. Moreover, the future spaceborne spectrometer will be able to attain calibration of the radar backscattering coefficients using multibeam joints. |
| Key words: spectrometer power spectrum estimation two-dimensional ocean wave spectra 180° ambiguity |
