海洋溢油乳化物的光学遥感模型研究

Marine oil emulsion is derived from oil spill accident and can generate environmental side-effects. Remote detection and quantification of oil emulsion improves the emergency response plan of oil spill accident and assessment of its environmental impact, thus representing one of the key research directions in marine environment monitoring. During marine oil spill accidents, notable optical remote sensing characteristics have been observed for oil emulsions (water-in-oil or oil-in-water) with different volume concentrations. Therefore, detection, classification, and quantification of different oil emulsions through optical remote sensing are possible and need further investigations. In this study, hyperspectral data of different oil emulsions will be collected from in-situ experiments, spaceborne and airborne multi/hyper-spectral optical sensors that have detected oil spill accidents. From these observation data, the optical remote sensing features of the oil emulsions, such as the morphological and spectral response features as well as their variations, will be further examined, which will be used to identify and extract oil emulsions from different optical remote sensing imageries. The oil emulsions undergo different optical processes when interacting with light − they can reflect, absorb, and scatter the incident light − resulting in different levels of contrast from the surrounding oil-free water and thus facilitating the development of optical models and key parameters to improve the remote quantification of oil emulsions. In addition, the oil emulsion surface sunglint reflectance can be corrected by refining the refractive index and surface roughness. The corrected reflectance will be further used to estimate the volume concentrations of different oil emulsions, with remote sensing imageries obtained of the Gulf of Mexico oil spill accident. The retrieved results will be verified by the field investigation report. Optical remote sensing is expected to play an increasingly important role for assessing marine oil spills.

海洋溢油会形成不同的溢油乳化物，对环境造成显著危害。准确识别溢油乳化物类型并估算其浓度，有助于海洋溢油污染应急处理与损害评估。溢油乳化物存在油包水相、水包油相两种类型，并具有体积浓度的差异。不同类型、不同浓度溢油乳化物的光学遥感响应特征差异明显，光学遥感技术具备对其进行识别分类与定量估算的能力。鉴于其光学遥感响应机理与定量估算研究的不足，本研究拟（1）通过室内外高光谱模拟实验，结合典型溢油污染的多源光学遥感影像，研究油包水相、水包油相溢油乳化物的光谱响应特征及变化规律。（2）研究溢油乳化物的多源光学遥感识别特征，实现其光学遥感识别与信息提取。（3）分析溢油乳化物的光学作用过程，构建其体积浓度的遥感估算模型及关键参数查找表。在对溢油乳化物表面太阳耀斑反射率精确计算的基础上，准确估算溢油乳化物的体积浓度。开展模型方法的遥感应用，利用现场调查数据进行检验评价，促进海洋溢油污染的光学遥感研究。

溢油是海洋环境遥感监测的重要对象，在海洋环境动力等作用下（如风化、扩散、乳化等），会形成复杂多样的溢油污染类型，对海洋与海岸带生态环境产生不同的危害。利用光学遥感技术识别复杂溢油污染类型，实现溢油量估算，能为溢油的应用处理与灾损评估提供技术方法支撑。本项目取得的成果主要体现在：（1）突破了不同溢油污染类型的实验仿真技术，首次系统性测量了不同溢油污染类型的反射光谱与吸收光谱，厘清了不同溢油污染类型的光学特征差异；（2）基于光学特征差异，构建了海洋溢油污染光学遥感的分类体系，创新性的提出了油包水状、水包油状溢油乳化物，发展了机载高光谱溢油污染识别分类与定量估算方法；（3）阐明了不同溢油污染的光学辐射传输过程，厘清了溢油海面耀光反射成因与计算方法，通过准确计算并消除溢油海面的耀光反射，获得溢油内部的光学信号，从而提高海洋溢油识别、分类与估算精度；（4）实现了对海面溢油的油膜厚度、乳化油浓度、等效溢油量等进行估算的能力，构建遥感反演模型，促进海面溢油的定量遥感估算；（5）研究成果服务于国产自主海洋水色业务卫星的应用，促进了中国海洋一号C/D卫星的海面溢油遥感应用实践；（6）开展多源遥感综合应用，对中国近海重大突发性溢油事件（2018年东海“桑吉”轮溢油事件）监测，取得较好的应用成效。在本项目支持下，由科学出版社出版发行海洋溢油光学遥感理论与应用实践专著1本，在Remote Sensing of Environment，IEEE Transactions on Geoscience and Remote Sensing，ISPRS Journal of Photogrammetry and Remote Sensing，Optics Express, 科学通报等国内外期刊论文14篇（SCI论文11篇、中文3篇），授权专利2件；项目还培养研究生6人毕业，多人次获得国内外奖励（江苏省优秀硕士论文1人、国家奖学金3人、获得美国高校的校长奖学金1人等）；项目开展了广泛的国内外交流与合作，取得明显成效；研究成果为中国近海溢油光学遥感的应用拓展奠定了良好的理论、方法与数据基础。