包含非线性调制项校正的波谱仪海浪谱反演模型研究

中法海洋卫星搭载了世界上第一台星载波谱仪已在轨运行近半年，其主要科学目标之一是实现全球范围内海浪谱高精度探测。目前国内外均使用线性调制谱模型，从波谱仪测得的调制谱中线性反演出海浪谱。然而实际的调制谱中除包含海浪谱的线性调制项外，还包含由地形模糊、电磁项和海面非高斯性产生的三种非线性调制项，它们的贡献此消彼长，在某些入射角和海况风速下，总的非线性效应较大，导致海浪谱线性反演精度下降。为解决该难题，本项目将深入研究非高斯海面多元统计特性表达与求解，建立包含上述三种非线性效应的波谱仪海面调制谱解析模型；探究海面要素与观测要素影响调制谱的物理机制，发展包含三种非线性调制的波谱仪调制谱蒙特卡洛仿真方法；结合调制谱对海况参数与雷达观测参数的敏感性分析，构造包含非线性调制项校正的海浪谱反演模型。本项目发展和完善了小入射角雷达海浪谱探测理论，对保证和提高中法海洋卫星波谱仪海浪谱探测精度具有重要意义。

The first satellite carrier spectrometer in the world has been on orbit for nearly half a year. One of its main scientific objectives is to achieve high-precision detection of ocean wave spectrum. At present, the linear modulation spectrum model is used at home and abroad to linearly invert the ocean wave spectrum from the modulation spectrum measured by the spectrometer. However, in the actual modulation spectrum, besides the linear modulation term of the wave spectrum, there are also three kinds of non-linear modulation terms, which are generated by terrain ambiguity, electromagnetic term and sea surface non-Gaussian. Their contributions increase and decrease. Under some incident angles and sea conditions, the total non-linear effect is larger, which leads to the decline of the accuracy of the linear inversion of the wave spectrum. In order to solve this problem, this project will deeply study the expression and solution of multivariate statistical characteristics of non-Gaussian sea surface, establish the analytical model of sea surface modulation spectrum of spectrometer including the above three non-linear effects, explore the physical mechanism of the influence of sea surface factors and observation factors on modulation spectrum, develop Monte Carlo simulation method of the modulation spectrum of spectrometer containing three non-linear modulations. Based on the sensitivity analysis of modulation spectrum with sea state parameters and radar observation parameters, a wave spectrum inversion model with correction of non-linear modulation term is constructed. This project develops and improves the theory of small incident angle radar wave spectrum detection, which is of great significance to ensure and improve the accuracy of wave spectrum detection of French Ocean Satellite Spectrometer.