By Madeleine Gregory
South Korea is facing a water quality problem. Climate change has brought more rainfall to the region, which has increased pollution in the country’s rivers and lakes and led to a decrease in water quality. This change significantly impacts ecosystems and human health, yet comprehensive, country-wide studies of water quality remain scarce. To address this gap, researchers Hyunglok Kim (PI) and Seongjun Lee (master’s student) from the Gwangju Institute of Science and Technology (GIST) embarked on developing a model to predict water quality indicators in near real-time.
Kim and Lee used Harmonized Landsat Setinel-2 (HLS) data to estimate water quality indicators such as chlorophyll-a, dissolved oxygen, and pollutants. As climate change continues to alter conditions in South Korea, this research will be essential to monitor how the nation’s shifting water quality.
What is one major takeaway from your research?
During the research process, we confirmed that even in the same water body, there were differences in the Chlorophyll-a prediction results for rivers and lakes. In our future research, we need to consider how to reflect these differences in our predictions of Chlorophyll-a concentrations for inland water.
Why did you use HLS in this work? Did it give you any insight that would have been difficult to get otherwise?
We used HLS because it is high-quality optical satellite data. The 30-m spatial resolution and about 2-3 days revisit time with combined use of Landsat and Sentinel-2 data allows for us to take into account differences in water quality across space and time.
What does Chlorophyll-a tell us about water quality?
Chlorophyll-a in water tell us the state of water pollution. High levels of Chlorophyll-a are indicative of the growth of algae which results in increased turbidity in the water and decreased oxygen levels in the water as the algae die and decompose. This causes substantial damage to underwater ecosystems.
Are there any research questions you’re interested in that build off of this work?
We’re interested in exploring if it is possible to determine the characteristics of rivers and lakes using only the spectral data collected satellites.
Co-authors:
Hyunglok Kim
Assistant Professor, School of Environment and Energy Engineering
Seongjun Lee
M.S. Student, School of Environment and Energy Engineering
Funding Acknowledgment: This research was supported by the BrainKorea21 Four Project of the National Research Foundation of Korea.
