太湖遥感反射率变化特征及其影响因素分析

An Analysis of the Variation Features and Influential Factors of the Remote Sensing Reflectance of the Taihu Lake

基于2010年10月4—8日在太湖全湖范围32个样点的水体光学参数和理论数值模拟结果,研究了太阳天顶角θ、散射系数和吸收系数的比值b/a及表征光场分布的参数Q对太湖遥感反射率变化的影响。结果表明,遥感反射率随θ的增大而增大,且当θ较小(0°～20°)或较大(80°～89°)时,其变化对遥感反射率增幅的影响较小;当b/a增大时,遥感反射率也随之增大,二者变化趋势呈显著正相关;Q较大时(如6～7),其变化对遥感反射率增幅的影响较小;Q较小时(如2～3),其变化对遥感反射率增幅的影响明显;遥感反射率随Q的增大呈递减的趋势。

The spectral data and numerical analyses of the Taihu Lake during the period of October 4-8,2010 were used to analyze the influence of solar zenith θ,the ratio of scattering and absorption coefficient b/a and parameter Q upon the variation of remote sensing reflectance.According to the results,remote sensing reflectance increases with solar zenith θ,while θ changes in the range of 0°~20° or 80°~89°,which has little influence on the growth of remote sensing reflectance.Remote sensing reflectance increases with the increase of b/a,and there obviously exists a positive relation between them.When Q is large（6~7）,its alteration has little effect on the variation of remote sensing reflectance.On the contrary,when Q is small（2~3）,its variation has enormous impact on the growth of remote sensing reflectance.Remote sensing reflectance tends to decrease with the growth of Q.