长江口春季潮周期内总悬浮颗粒物浓度的光学遥感反演

发布时间：2018-10-29 17:54

【摘要】：长江河口水域由于受径潮流相互作用和高含沙量影响,水体光学特性具有特殊性.同一潮周期内大潮时总悬浮颗粒物浓度能达到0.5 kg/m~3以上,而小潮时最大总悬浮颗粒物浓度只有大潮的1/3,高总悬浮颗粒物浓度和潮周期内较大的变差,使得很多经验算法无法取得良好的反演效果.为了能适应该区域特殊水体特性,通过改进总悬浮颗粒物的复杂指数模式,建立了适合长江口地区的改进模式.利用2014年5月航次现场光学和同步水沙数据分析了长江河口地区总悬浮颗粒物浓度随着潮周期的变化特征,在原有7个备选波段的基础上引入了806nm和858 nm两个备选波段,补充近红外波段峰面积指数作为复杂指数模式的第五个指数,将复杂指数与总悬浮颗粒物浓度的对数之间线性关系改进为二次多项式关系,针对不同潮情的水体特性建立了分潮情的改进模型.结果表明:改进的模型可以适用于长江口水域,大、小潮分别建模得到的反演精度较大小潮统一模型更高,能更好地刻画潮周期内离水辐射的变化,反映总悬浮颗粒物浓度的潮周期变动.
[Abstract]:Due to the interaction of diameter tidal current and high sediment content, the optical properties of the Yangtze River estuary are special. In the same tidal cycle, the total suspended particulates concentration in the spring tide can reach more than 0.5 kg/m~3, while the maximum total suspended particulate matter concentration in the low tide is only 1 / 3 of that in the spring tide. Many empirical algorithms can not achieve good inversion results. In order to adapt to the special water body characteristics in this area, an improved model suitable for the Yangtze Estuary was established by improving the complex exponential model of total suspended particulate matter. The variation characteristics of total suspended particulate concentration with tidal cycle in the Yangtze River estuary are analyzed by using the May 2014 navigation field optical and synchronous water sediment data. Two alternative bands, 806nm and 858 nm, are introduced on the basis of the original seven alternative bands. As the fifth exponent of the complex exponential model, the linear relationship between the complex index and the logarithm of the total suspended particulate concentration is improved to quadratic polynomial relationship. Based on the characteristics of different tidal conditions, an improved model was established. The results show that the improved model can be applied to the Yangtze River Estuary. The inversion accuracy of the large and low tides is higher than that of the uniform model of the large and small tides, and it can better describe the variation of the off-water radiation in the tidal period. The change of tide cycle reflects the concentration of total suspended particulates.
【作者单位】：华东师范大学河口海岸学国家重点实验室;
【基金】：国家自然科学基金(41376098) 上海市科学技术委员会重大项目(13dz1204900)
【分类号】：P715.7;P736.2

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