基于水动力学的水体组分垂直结构对遥感信号的影响

基于水动力模型和辐射传输模型,模拟不同风速条件下水体组分(浮游植物和悬浮颗粒物)垂直分布对遥感反射率的影响,对比分析现有的两种水体光学均一函数(Zaneveld权重函数和Gordon权重函数)在不同层化程度水体中的应用。结果表明,悬浮颗粒物垂直分布对500～650nm范围内的遥感反射率(Rrs)影响较大,随着参考深度悬浮颗粒物质量浓度增加(由5～70mg/L),悬浮颗粒物垂直分布对Rrs的影响不断减小(变异系数由27.46%减小到3.38%),同时Rrs受到悬浮颗粒物影响的最大波长位置向长波方向移动(由585nm逐渐移动到685nm);在浮游植物垂直分布影响下,400～725nm范围内的Rrs值随着风速的增加呈现先增加再逐渐减小趋势,400～450nm范围内的Rrs受浮游植物垂直分布影响较小,变异系数仅为1%;500～600nm范围内的Rrs受浮游植物垂直分布影响较大,最大变异系数可达27.18%。在水体组分层化较弱水体中,Zaneveld与Gordon权重函数对水体光学均一处理效果较为相似;但在水体组分层化较为严重的水体中,Zaneveld权重函数光学均一处理效果要好于Gordon权重函数。

Influence of Vertical Distribution of Water Consistuent on the Remote Sensing Based on Hydrodynamics

Based on the models of hydrodynamics and radiation transfer, the remote sensing reflectance (Rrs) affected by different water constituents′ vertical distribution under the condition of different wind speeds is simulated. The calibration effect of two different water optical homogeneous functions (Zaneveld and Gordon weight function) in the stratified water mass is compared and analyzed. The results indicate that the Rrs in the range of 500~650 nm is significantly affected by the vertical distribution of suspended particle. With the increasing of suspended particle concentration (5~70 mg/L) at reference depth, the influence of suspended particle matter vertical distribution to the Rrs becomes smaller and smaller (the variation coefficient induced by suspended particle decreases from 27.46% to 3.38%). And the biggest influencing wavelength position on Rrs moves to the long wavelength (585~685 nm). With the increasing of wind speed, the influence of phytoplankton vertical distribution on Rrs in the range of 400~725 nm increases firstly and then decreases. The influence of phytoplankton vertical distribution on Rrs in the range of 400~450 nm is the smallest. The variation coefficient induced by phytoplankton vertical distribution is only 1%. The influence of phytoplankton vertical distribution on Rrs in the range of 500~600nm is the biggest. The variation coefficient induced by phytoplankton vertical distribution can reach 27.18%. The effect of optical homogeneous calibration by the Zaneveld weight function is similar with Gordon weight function when the stratification of water mass is insignificant. However, the effect of optical homogeneous calibration by the Zaneveld weight function is better than Gordon weight function when the stratification of water mass is significant.