采砂扰动下鄱阳湖水体剖面光学特性及其对遥感反演的影响研究

Take large shallow Poyang Lake, which has under gone the combined impact of the complicated hydrodynamic conditions of lake and the intense dredging activities, as research area. Integrating hydrodynamic simulation with water optical radiation transfer simulation, the study explores how stratification differentiation of water and sand influences water optical properties and remote sensing retrieval under dredging disturbance. The study focuses on following aspects:1) Study on vertical profile observation of water components and water optical properties in Poyang Lake and its spatial-temporal characteristics. These are bases for parameter optimization of water biological optical model of Poyang Lake.2) Simulates the transportation and deposition of suspended sediment in Poyang Lake and analyses the impact and scope of influence on spatial distribution of suspended sediment, exerted by dredging disturbance. Under dredging disturbance, the vertical profile distribution of suspended sediment in Poyang Lake is revealed.3) Validates how the dredging disturbance affects the vertical distribution of water optical properties, and studies on feedback mechanism of biological optical properties to vertical distribution of suspended sediment. On that basis, we discuss the influence of dredging disturbance on accuracy of water remote sensing retrieval model in Poyang Lake. This study can provide new methods and techniques for lake water quantitative remote sensing inversion.

本研究拟针对复杂的湖泊自然水动力条件和强烈的采砂人为活动共同影响大型浅水湖泊-鄱阳湖，将水动力-泥沙输移数值模拟与水体光学辐射传输模拟相结合，探索采砂扰动下水沙层化分异对水体生物光学特性、底质贡献和遥感反演算法的影响机制。本研究从以下三个层面展开：1）开展鄱阳湖水体水色要素及水体光学特性的垂直剖面观测，研究其时空差异特征，为鄱阳湖水体生物光学模型的参数优化奠定基础；2）模拟鄱阳湖悬浮颗粒物的输移、沉积过程，结合现场观测与实验室分析，探讨采砂扰动对鄱阳湖悬浮颗粒物空间分布的影响区域与程度，明确采砂扰动下鄱阳湖水体悬浮颗粒物垂直剖面分布规律；3）评估采砂扰动对鄱阳湖水体光学特性垂直分布的影响范围与深度，研究生物光学特性对悬浮颗粒物垂直分布的反馈机制，探讨采砂活动对鄱阳湖水色遥感反演模型精度的影响。该研究可为完善湖泊水色参数遥感定量反演方法体系提供新的方法与技术。

项目旨在针对复杂的湖泊自然水动力条件和强烈的人为活动共同影响的浅水湖泊，通过制定野外多方案观测获取湖泊特征，监测人为活动，利用水动力模拟自然过程，从而实现水体光学辐射传输定量评价遥感监测结果的目的。目前，项目在鄱阳湖水体垂直分布时空特征观测与分析、采砂扰动对湖泊光学特性时空影响、浅水湖泊遥感定量反演模型，以及采砂扰动对遥感反演影响机制方面取得一定进展。后续将进一步围绕水环境时空分析与人类行为的经济驱动因素与评价问题开展研究。