한반도 부근 Case-II 해역에 대한 랜샛 위성자료의 활용

Abstract

Application of the Landsat TM/ETM+ signal over aquatic environment requires the retrieval of wa-ter-leaving radiance (Lw) from the total radiance recorded at the top-of-the-atmosphere (TOA) and thus of the water constituents’ of interests. Retrieval of Lw from the TOA signal using certain algo-rithm is referred to as the atmospheric correction, which over aquatic environment is more de-manding than over land because the signal from the water column is small and it carries immense information about biogeochemical variables in the ocean. This paper describes methods for the atmospheric corrections and suspended sediment algorithms in the Landsat TM/ETM+ imagery, especially from Case-II waters around Korean peninsula. Three atmospheric correction methods implemented and examined, using the TOA radiance or reflectance data, are path extraction and spectral shape matching methods (SSMM). Validation suggests that accurate the retrieval of wa-ter-leaving radiance is not feasible with the invalid assumption of the classical AC algorithms, but is feasible with SSMM. The goal of performing the atmospheric correction with SSMM to estimate suspended sediment (SS) concentration, using Landsat TM/ETM+ SS algorithm, has also been demonstrated on the Landsat TM/ETM+ imagery acquired over the highly turbid Wan-do and Jin-do bays of Korea.