基于遥感传输和颗粒光学的近似方法遥感估算沿海浑浊水体光学和生物地球化学参数

The goal of this project is to develop algorithm and code allowing a satellite water quality monitoring of Changjiang (Yangtze) River Estuary (YRE) and adjacent coastal area (ACA). An algorithm will be based on the in situ laboratory and remote sensing measurements along with using ocean and atmospheric optics, particulate optics and radiative transfer approximations. We are planning to use up-to-date achievements in these scientific fields for modeling of optical and biogeochemical properties and processes occurring in the atmosphere, water, and air-water interface. A significant part of these achievements are our own what were developed, verified and published during last decade. Necessity of using new, more precise methods follows from the fact that a majority of the optical methods developed worldwide are applied for a clear oceanic (so-called, "Case 1") waters and barely may be applied to the turbid coastal and inland (so-called, "Case 2") waters. These two types of waters have a large difference between them, expressed, for example, in stronger absorption and scattering, larger average particles' size and stronger temporal and spatial variability in optical and biogeochemical properties for Case 2 waters comparative to Case 1 waters. Today a great attention is given just for optically complicated Case 2 waters. Another reason for this, in addition to importance of coastal and inland waters for human being, is a fast progress in satellite and airborne sensors development. Modern ocean color satellites are supplied by multispectral sensors with a spatial resolution up to 250m x 250m, that allows using remote-sensing methods for relatively small geographical objects. Thus, our project assumed to use all advantages of such sensors and novel approaches for assessment of optical and biogeochemical variables in turbid coastal waters. In the course of this project we assume to develop a series of new, more flexible and accurate methods for the following aims: - A model related the spectral surface remote-sensing reflectance Rrs with the spectral radiometric quantities - An algorithm for scattering correction for the measured absorption - Analytical models related inherent optical properties (IOPs) and apparent optical properties (AOPs) - Atmospheric correction algorithm - An air/water interface reflectance algorithm - An algorithm for estimating a complex refractive index and particles size distribution from measured IOPs.

沿海和内陆水域的高浊度水体与人类生存息息相关。然而，目前全球已开发的卫星海洋水色/水质监测的光学方法大多数针对清洁海域水体，鲜有可用于近岸和内陆浑浊水体的。而且这两类水体在光学和生物地球化学特性上都有很大差异。因此，本项目拟以现场和遥感观测为基础，采用海洋和大气光学、颗粒光学和辐射传输模型的近似计算，研制用于沿岸和近海浑浊水体的卫星水色/水质参数定量反演方法，并结合高空间分辨率海洋水色遥感卫星资料，评估长江口及其邻近海域浑浊水体的光学和生物地球化学参数。关键内容聚焦在几个方面：海表遥感反射率与水体剖面辐射测量参数的关系模型；现场水体吸收测量与估算的散射校正方法；固有光学特性(IOPs)和表观光学特性(AOPs)的分析型关系模型；大气校正方法；水汽界面反射率计算；利用IOPs估算水体颗粒复折指数和粒径分布的模型与算法。拟通过这几方面的研究开发出一系列新的、更为灵活和精度更高的计算方法。

1. 研究背景.由于长江口（YRE）及其毗邻沿海地区（ACA）对该地区周边稠密人口具有巨大的价值，因此研究此项目十分重要。长江流域以富集很多工业和城市中心为特征，特别是长江下游和河口地区。随着人口增长，化肥和生活垃圾的大量使用，长江口面临着环境恶化的挑战。总的来说，有两个主要因素决定了对该地区进行环境调查的重要性：1）水生生态系统状况恶化; 2）该地区对稠密人口的环境响应。.对此地区进行永久性的现场和遥感监测，是直接防止状况进一步恶化的重要紧急措施之一。为此，我们的研究小组（Leonid Sokoletsky博士和沈芳博士，以及学生杨宪平，刘越，魏小岛，王永超，潘燕群，孙学荣）在该地区进行了多次实地观测，收集了大量的卫星资料，并利用最先进的辐射传输理论和大气与海洋光学成果，对采集到的现场和遥感数据进行分析。..2. 本研究使用了三个关键数据库：.—2013-2017年期间在YRE和ACA地区收集的光学特性;.—2013-2017年期间，卫星传感器在YRE和ACA地区接收的大气顶层（TOA）上行光谱辐亮度;.—IOP和AOP的合成数据集。..3. 此研究的科学意义：.—已发现用于透射和反射光的辐射传输方程的新解析解，这可以显著提高海洋和大气光学中解的精度;.—已开发用于现场和遥感的精确可靠的光学方法。