Publications

Chen, XD; Liu, LY; Zhang, X; Li, JS; Wang, SL; Liu, D; Duan, HT; Song, KS (2021). An Assessment of Water Color for Inland Water in China Using a Landsat 8-Derived Forel-Ule Index and the Google Earth Engine Platform. IEEE JOURNAL OF SELECTED TOPICS IN APPLIED EARTH OBSERVATIONS AND REMOTE SENSING, 14, 5773-5785.

Abstract
Water color is an important parameter in water quality assessment. However, the existing water color investigations have mostly focused on the lakes with areas greater 1 km(2). In order to improve the understanding of the color of water bodies in China, a cloud-free composite image of China for the summer of 2015 was generated using time-series of Landsat-8 imagery and the best-available-pixel (BAP) compositing algorithm. Then, the first Forel-Ule index (FUI) water color product with a resolution of 30 m was produced for China using the generated BAP composite and the Google Earth Engine computing platform. Finally, the first national-scale assessment of the FUI of natural lakes with an area >0.01 km(2) (N = 60026) was conducted based on the generated FUI product. The generated FUI product was shown to have a high degree of consistency with in situ water surface reflectance-derived FUI (R-2 = 0.90, P < 0.001). Also, it had a high degree of consistency with the in situ Secchi depth (R-2 = 0.90, P < 0.001) and trophic level index (R-2 = 0.62, P < 0.001) datasets. In addition, we found that the most prevalent lake colors in China were yellow (about 49%) and green (about 41%). Besides, the proportion of small lakes (areas < 1 km(2)) found to be yellow was much larger than for large lakes (area >= 1 km(2)) (50% against 28%). Our results will provide important information that can be used for preserving and restoring inland water resources.

DOI:
10.1109/JSTARS.2021.3085411

ISSN:
1939-1404