鄱阳湖丰水期水体后向散射特性研究

后向散射是获取湖泊水体光学活性物质遥感信息的关键，针对无机悬浮物为主的浑浊二类水体， 其对水体表观光学性质有着决定性的影响，研究表层水体后向散射特性在提高湖泊光学活性物质遥感反演精度方面具有重要的意义.该文通过2017年6月在鄱阳湖丰水期36个站点的巡航监测，分析了水体后向散射特征及其与光学活性物质的关系，并利用指数模型对后向散射系数进行参数化.研究结果表明：在420～700 nm波段范围内，水体后向散射系数、后向散射概率随波长的变动趋势较为一致，均随着波长的增大呈指数函数减小；空间上水体后向散射系数的均值和变幅为南湖区>主湖区>北湖区；总悬浮颗粒物浓度与后向散射系数之间的相关性随波长增大而增大，其中700 nm波段的相关性最好，R2达到0.760；随着波长的增加后向散射系数与叶绿素a含量的相关性减少；同时建立了后向散射系数光谱模型，斜率指数为1.229,470～700 nm波段平均绝对百分比误差均小于8%，具有较好的反演精度.

The characters of backscattering coefficient during flood period in Poyang Lake

Backscattering is the key to obtain remote sensing information of optical active substances in lake. The turbid case II water， which is the main components of inorganic suspended particulates， has a decisive influence on the change of the optical properties of the water body. It is of great significance to research the backscattering characteristics of surface water body in improving the retrieval accuracy of optical active substances in lakes. In June 2017， 36 sites in Poyang Lake were monitored for cruise monitoring during the flood period. The characteristics of the backscattering parameters of the water and its relationship with optical active matters were analyzed. The backscattering coefficients were parameterized using an exponential model. The results show that the variation trend of backscattering coefficient and backscattering probability in the wavelength range of 420－700 nm are consistent with the wavelength， which both decrease with exponential power as the wavelength increases. The mean and amplitude of the backscattering parameters are spatially analyzed， which is southern lake district＞main lake district＞northern lake district. The correlation between the total suspended solids concentration and the backscatter coefficient during the flood period increases with the increase of wavelength， and the correlation at 700 nm is the best with the R2 of 0.760. However， the correlation between the Chlorophyll-a contents and the backscatter coefficient during the flood period decreases with the increase of wavelength. At the same time， the backscattering coefficient spectral model is established with the slope index of 1.229， which has good inversion accuracy at the wavelength of 470－700 nm with the mean absolute percentage error less than 8%.