微波遥感海水盐度的算法和影响因素分析

【作者】 王杰；

【导师】 赵进平； 史久新；

【作者基本信息】 国家海洋局第一海洋研究所 ， 物理海洋学， 2007， 硕士

【摘要】 海表面盐度是研究大洋环流和海洋对全球气候影响的重要参量,但是至今未实现卫星遥感。盐度遥感已成为海洋遥感的一个重要研究方向。本文的工作主要是研究微波遥感海水盐度算法的反演误差,并且对盐度遥感的影响因素进行分析,确定修正方法。本文将盐度遥感的反演算法分为双波段算法和单波段算法两类。双波段算法包括二元多项式拟合算法和半解析算法,都是用L/S双波段亮温进行反演。原有的单波段算法是利用L波段亮温和海面温度反演盐度,本文提出了利用L波段的H/V双极化亮温反演温度和盐度的新算法。通过理想数据和实测数据对以上算法进行了比较,结果表明半解析算法的盐度反演精度最高。入射角和极化方式对反演精度也有影响,L波段采用双极化时盐度反演精度最高,其次是V极化,H极化最差;S波段的极化方式也对盐度反演的精度有影响;入射角越小,不同极化方式之间的差别越小。本文从太空、海面和大气3个方面总结了盐度遥感的影响因素,并建立了修正公式,对每项因素进行了分析和计算。本文最后利用2005年9月10日在北黄海获得的航空遥感和海面现场比测数据,分别用半解析的双波段和单波段反演算法进行了盐度反演,并且用亮温修正公式对实验数据进行修正,进行比较。结果表明,双波段双极化反演组合是微波遥感盐度反演最好的选择,得到的盐度反演精度可达0.5;仅利用L波段H/V极化亮温的单波段算法也是可行的,但是精度要低于双波段算法。考虑影响因素后的反演精度高于不考虑影响因素的反演精度。更多还原

【Abstract】 Sea surface salinity is an important parameter in studying ocean circulation and the effects of ocean on the global climate, but has not achieved the satellite remote sensing. Salinity remote sensing has become an important research field in marine remote sensing. The main task of this paper is to study the retrieval error of salinity retrieval algorithm in terms of ocean salinity microwave remote sensing, analyze the influencing factors of salinity remote sensing and determine the correction method.In this paper, the retrieval algorithm of salinity remote sensing is divided into two kinds: single-band algorithm and dual-band algorithm. Dual-band algorithms includes binary polynomial fit algorithm and semi-analytical retrieval algorithm, both of which are using L/S dual-band brightnesses. The original single-band algorithm of retrieval salinity and temperature is using brightness of L-band and sea surface temperature, and the new algorithm proposed in this paper is using perpendicularity-polarization brightness and horizontal-polarization brightness of L-band. By processing the ideal data and the measured data, the algorithm mentioned above are compared and the results show that semi-analytical retrieval algorithm has the highest salinity retrieval precision. Incidence and polarization also affect the retrieval precision. The salinity retrieval precision is the highest when L-band using dual-polarization, using perpendicularity-polarization is second best and using horizontal-polarization is the worst. Meanwhile, the polarization of S-band also influences the precision of salinity retrieval. The smaller the incidence is, the smaller the differences between various polarization modes are. In this paper, the influencing factors on the salinity remote sensing are summarized in three aspects: outer space, sea and atmosphere. Besides, we have established modified formula and each influencing factor is analyzed and calculated. Finally, using the measured data of airborne remote sensing and marine surface in northern yellow sea obtained on September 10, 2005, salinity retrieval are carried out with dua-band algorithm and single-band algorithm of simi-analytical retrieval algorithm, repectively. The measured experiment data are modified with modified formula of brightness, and then compared carefully. The results show that the combination of dual-band and dual-polarization is the best choice for salinity microwave remote sensing retrieval and the salinity retrieval accuracy is 0.5. Single-band algorithm of using dual-polarization brightness is also feasible, but the precision is worse than that of the dual-band algorithm. The inversion precision when considering the influencing factors is highest than that when not considering these factors.更多还原