太湖、巢湖水体总悬浮物浓度半分析反演模型构建及其适用性评价

Construction of Semi-analytical Model for Inversing Total Suspended Matter in Lake Taihu and Chaohu and Assessment of Its Applicability

总悬浮物浓度是水体重要的水质参数.本研究利用太湖春季、秋季和巢湖夏季多期野外实测数据,通过对生物光学模型进行合理的简化构建适用于太湖、巢湖水体总悬浮物浓度反演的半分析模型,并将该模型应用于MERIS和环境一号卫星高光谱卫星影像上以验证该方法的适用性.结果表明:①针对太湖和巢湖水体,总悬浮物浓度最优反演波段范围为730～832nm(氧气吸收带除外);②针对MERIS数据,波段10(中心波长754 nm)和波段12(中心波长779 nm)均适用于太湖总悬浮物浓度反演,而波段11(中心波长761 nm)由于氧气吸收带的影响不适用于总悬浮物浓度反演;③针对太湖MERIS数据,模型反演结果的相对误差基本上呈现出随距离卫星过境时间增大而逐渐增加的趋势,在卫星过境时间正负3 h内测量的样点,模型反演结果的相对误差均在50%以内,而时间差超过3 h,相对误差则逐渐增大到50%以上;④环境一号卫星高光谱数据17个波段(B83～B99)均能够对巢湖总悬浮物浓度进行较好的反演,其反演效果要好于MERIS数据在太湖的反演结果.

Total suspended matter is an important water quality parameter.Firstly,a semi-analytical model for inversing concentration of total suspended matter was constructed by simplifying the bio-optical model,using the in-situ data of Lake Taihu in spring and autumn and that of Lake Chaohu in summer.And then,its applicability was validated by MERIS and HJ-1 HSI data.The results showed that： ① The optical range for inversing total suspended matter in Lake Taihu and Chaohu was between 730 nm and 832 nm except the oxygen absorption bands.② According to MERIS data,bands centered at 754 nm and 779 nm were both suitable for inversing total suspended matter in Lake Taihu whereas the band centered at 761 nm was not suitable due to the influence of oxygen absorption.③ According to MERIS data,the relative error of this model increased with the time difference after satellite transit time.The relative errors of inversion results of this model were below 50% when the time difference was less than 3 hours,while they increased to more than 50% when the time difference exceeded 3 hours.④ The seventeen bands of HJ-1 HSI data were all suitable for inversing total suspended matter in Lake Chaohu and its result was better than that in Lake Taihu using MERIS data.