华东师范大学学报(自然科学版) ›› 2016, Vol. 2016 ›› Issue (3): 146-155.doi: 2016.03.016

• 河口海岸学 • 上一篇    

长江口潮周期内总悬浮颗粒物浓度的光学反演算法分析

马骅,蒋雪中   

  1. 华东师范大学~~河口海岸学国家重点实验室, 上海200062
  • 收稿日期:2015-03-05 出版日期:2016-05-25 发布日期:2016-09-22
  • 通讯作者: 蒋雪中, 男, 副教授,主要从事河口海岸变化与GISRS应用研究. E-mail:xzjiang@sklec.ecnu.edu.cn
  • 作者简介:马骅, 男, 硕士研究生, 主要从事河口水体变化及其光学效应研究
  • 基金资助:

    国家自然科学基金(41376098);

In consideration of tidal condition to improve optical inversion algorithm on total suspended matters concentration according to in situ measurement in the Yangtze Estuary

 MA  Hua, JIANG  Xue-Zhong   

  • Received:2015-03-05 Online:2016-05-25 Published:2016-09-22

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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~806~nm~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

关键词: 水色要素, 总悬浮颗粒物浓度, 潮汐周期, 遥感反射率, 长江河口

Abstract: Due to the interaction between the river discharge and the tide, as well as the high suspended sediment concentration in the surface water, the optical property of the Yangtze Estuary waters is different from the open sea waters. In a single tidal cycle, the total suspended maters (TSM) concentration can reach 0.5~kg/m{3} or more during spring tide, while in neap tide the maximum TSM concentration is only 1/3 of the spring tides. High TSM concentrations and a greater variation in single tidal cycle make a lot of empirical inversion algorithm unavailable in this region. A new algorithm was developed in the Yangtze Estuary, named improved complex proxy TSM (ICPTSM) model to improve the complex proxy TSM model. Using in situ synchronous optical and TSM concentration data
collected in the survey in May 2014, we analyze the characteristic of sediment concentration changing in the Yangtze Estuary associated within entire tidal cycle. Based on the original seven alternative bands, we introduce two alternative bands, 806~nm and 858 nm, as a supplement. We add a near-infrared peak area index as the fifth index to the complex proxy (CP). Linear relationship between the CP index and TSM concentration is improved into quadratic relationship. For water characteristics of different tidal conditions, individual ICPTSM models have been established. The results show that: ICPTSMmodel is adaptable in the Yangtze Estuary, distinction model toward spring and neap tidal have higher retrieval accuracy than unified model for a whole tide cycle, distinction model can better describe changes of water-leaving radiance, and TSM concentration changes in a tidal cycle

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