| 摘要: |
| 利用代价函数(cost function)方法, 通过分析粗糙海面L 和C 双波段多极化遥感亮温对海表盐度、温度、风速和有效波高等参数的敏感性以及L 和C 双波段多极化的代价函数收敛特性, 建立了反演海表盐度、温度、风速和有效波高等多参数的L 和C 双波段多极化代价函数模式。双波段遥感模式分析结果表明: (1)对于双参数的联合反演, L 和C 双波段垂直极化代价函数联合反演海表盐度和温度可以获得较好的反演结果。(2)L 波段垂直极化和C 波段水平极化代价函数联合反演海表盐度和风速较好。(3)对于三参数联合反演, L 波段垂直极化和C 波段的双极化联合反演盐度、温度和风速的精度较高。(4)L波段亮温对有效波高的敏感性较低(C 波段经验模式不含有效波高), 使得有效波高反演误差较大, L 和C 波段经验模式不适合反演有效波高参数。另外, 为了定量分析L 和C 双波段代价函数的多参量遥感反演结果, 采用加性噪音模拟亮温方法, 对上述L 和C 双波段多极化模式的盐度、温度和风速等多参数联合反演误差进行了分析, 均得出较好的结果。结论表明L 和C 双波段代价函数联合反演多参量可以明显提高参量反演精度, 为粗糙海表面多参量的反演提供了新的方法和途径。 |
| 关键词: 粗糙海面 代价函数 海表盐度 亮温 L 和C 双波段 |
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| 基金项目:国家863计划(2008AA09A403, 2009AA09Z102); 国家自然科学基金(40876094) |
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| Rough sea surface cost function retrieval models for L and C band |
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| Abstract: |
| Based on the cost functions of rough sea surface brightness temperatures, the sensitivities of L and C band brightness temperatures to sea surface salinity (Sss), temperature (Tss), wind speed (U10), and significant wave height (Hsw) were analyzed. By analyzing the cost function sensitivities of vertical and horizontal polarizations for both L and C band, the optimum polarization model was built for retrieving sea surface parameters. We found that (1) the vertical polarizations of both L and C band can be used to simultaneously retrieve Sss and Tss; (2) the vertical polarization of L band and horizontal polarization of C band can be adapted to retrieve Sss and U10 simultaneously; (3) the vertical polarization of L band combining with either vertical or horizontal polarization of C band was suitable for retrieving Sss, Tss and U10; (4) because of the low sensitivity of L band brightness temperature to Hsw parameter, the cost function of both L and C band can not be used to estimate Hsw. Furthermore, with the simulated brightness temperature of additive noises, the optimum multi-polarization models were used to retrieve Sss, Tss and U10. The retrieval results showed that these optimum models were reliable at a higher noise level. |
| Key words: sea surface roughness cost function sea surface salinity brightness temperature L and C bands |
