基于二维激光观测的溢油及其乳化过程散射模式研究

Synthetic aperture radar (SAR) is an effective microwave sensor to detect oil spills, which can image ocean surfaces during the day and night with high resolution and large coverage, independent of cloud cover. It plays a more and more important role in the process on the sea surface oil spill disaster emergency monitoring. Oil spill detection using SAR images relies on the oil slick to decrease the sea surface back-scatters of capillary - gravity wave which results in a dark formation that contrasts with the brightness of the surrounding spill-free sea. However, the emulsifying process of the sea surface oil spill directly affect observation precision of the scattering cross section in SAR. This project will be based on physical oceanography, principle of laser, and the sea surface electromagnetic scattering theory. Using laser scanner observed the sea surface roughness of oil spill establish corresponding relationship with the characteristic parameters of oil spill and the scattering coefficient, respectively. Coupling to the relationship between the characteristic parameters of oil spill with the scattering cross section by experiment. Using the electromagnetic scattering numerical modeling sets up the sea surface scattering model of oil spill and researches the oil spill emulsifying process to the influence of the scattering cross section. The project will be provided a possible to monitor the oil spill volume,the thickness of the oil spill and distribution pattern of the oil spill by SAR. It will further reveal the sea surface scattering mechanism of oil spill and improve the accuracy and ability of monitoring oil spill by SAR.

合成孔径雷达(SAR)以其高分辨率、能不受雨云影响实施全天时全天候全方位监测，在海面溢油灾害应急监测过程中发挥着越来越重要的作用。溢油是因为海面油膜抑制了毛细波和重力波，在SAR图像上呈暗斑而被识别。然而，海面溢油的乳化过程直接影响SAR对海面溢油后向散射截面的观测精度。本项目将以物理海洋学和激光原理以及海面电磁散射理论为基础，通过实验利用激光扫描仪观测海面溢油粗糙度，分别与溢油特征参数、后向散射系数建立对应关系；耦合海面溢油参数与后向散射截面的关系,利用电磁散射数值建模方法，建立海面溢油散射模型，研究海面溢油乳化过程对微波后向散射截面的影响。本项目的研究将为SAR监测海面溢油量、溢油厚度及油品分布格局提供了可能；将进一步揭示海面溢油的散射机制，提高SAR海面监测溢油的精度和能力.

合成孔径雷达(SAR)以其高分辨率、能不受雨云影响实施全天时全天候全方位监测，在海面溢油灾害应急监测过程中发挥着越来越重要的作用。但是SAR在观测油膜厚度及溢油量方面仍然存在“瓶颈”问题；本课题通过多手段联合乳化原油实验，从海面溢油的乳化过程对SAR后向散射截面的影响变化，以物理海洋学和激光原理以及海面电磁散射理论为基础，利用激光扫描仪、全极化散射计、高光谱成像仪等观测海面溢油粗糙度、后向散射系数（NRCS）、反演油膜厚分别与溢油特征参数建立对应关系；耦合海面溢油参数与NRCS的关系,利用电磁散射数值建模方法，通过多手段联合试验建立海面乳化溢油NRCS与油膜厚度之间的关系，研究了海面溢油乳化过程对微波NRCS的影响。本项目成功探索出三维激光扫描仪观测乳化油膜的粗糙度的方法；发现了含水率是描述原油乳化过程的最佳参数，原油乳化改变了原油的张力、粘度和密度从而改变了原油的介电常数，引起油面粗糙度的变化导致NRCS的变化；试验发现在没有波浪影响条件下，风速小于7m/s，水面波高‹3mm时，导致油膜的变化是由于乳化导致介电常数变大，影响水面粗糙度从而导致NRCS增加；通过油膜NRCS与近邻海水的NRCS差值与高光谱反演的油膜厚度拟合发现存在相关性；这种相关性的发现为实现SAR监测海面乳化油膜后厚度及溢油量提供了极大的可能，将进一步揭示海面溢油的散射机制；进一步提高SAR海面监测溢油的精度和能力。