Application of remote senisng technique and development of optical algorithms suitable for inland water in Korea,

Abstract

In recent years, eutrophication is a serious environmental problem all over the world due to a rapid global climate change. Relatively high temperautre and intensive precipitation could provide reasonable condition to growth of algae and provide nutrients from runoffs like nitrogen and phosphorous. Therefore, monitoring of algae and water quality constituents is essential to identify the problem and to provide a solution. A remote sensing technique is a useful tool to detect algae and water quality constituents in the ocean or inland water. But in Korea, It is unfeasible to apply this technique, especially in inland water. This is because optical monitoring for inland water is complicated. The inland water has many variations which are interferences such as colored dissolved organic matters (CDOM) and suspended solids (SS). In this study, by using spectro-radiometer, sampling of optical properties was carried out in water bodies of Korea. After Analyzing the optical data, empirical optical algorithms were applied to estimate chlorophyll-a, CDOM, and SS. Also, modification of the optical algorithm was needed because optical properties of different sampling places have their own optical characteristics. In this process, the consideration about CDOM and SS was a key part. These constituents could affect the performance of the algorithm which estimates the chlorophyll-a concentration. The performance of the algorithm was checked by comparing estimated results with measured results which were monitored at the same time during optical sampling. In addition, accuracy assessment was added to support it by calculating R square, Nash–Sutcliffe efficiency (NSE), and root mean square error(RMSE) These results will be the fundamental data to the remote sensing applications for airborne or satellite monitoring in Korea.