太湖二类水体水色遥感的大气校正问题探讨

Discussion on Atmospheric Correction of Water Color Remote Sensing of Case Ⅱ Waters in Lake Taihu

基于简化的大气辐射传输模型,提出一种基于图像本身的水色遥感大气校正方法。根据清洁水体在绿光波段的离水辐射相对稳定的特点,来估算清洁水体像元在绿光波段的气溶胶参数,插值获取整幅图像在绿光波段的气溶胶参数,根据大气校正因子为1的假设,外推获取蓝、红波段的气溶胶参数。以太湖为研究区,对Landsat5TM蓝、绿、红波段进行大气校正,反演出离水辐亮度,进而获得水体的遥感反射率。对反演的水体遥感反射率与准同步实测的相应采样点水体遥感反射率进行了对比分析,结果表明,该方法有效地去除了大气效应对遥感数据的影响,经过大气校正的反射率值接近实测反射率值。

A method of atmospheric correction of water color remote sensing using Landsat TM data was proposed based on simplified atmosphere irradiative transfer model.The water-leaving radiance over clear water was relatively constant at green band,which was used to calculate the contribution of aerosol scattering at corresponding band over these pixels.The image of aerosol scattering at the green band was generated by interpolation.The aerosol scattering at the blue and red bands were calculated by the assumption that the atmospheric factor were 1 at the TM visible bands.The Landsat 5 TM data over Lake Taihu at visible bands was atmospherically corrected.The remotely sensed reflectance was obtained from water-leaving radiance image.The comparison between the retrieved reflectance with the measured reflectance showed that the atmospheric effect on the remote sensing imagery was removed effectively,and the retrieved reflectance was close to the measured reflectance.