AUTHOR=Zhou Zheng , Wang Xingdong , Sun Zehao , Zhao Yanchuang 

TITLE=Study on extracting surface meltwater on the Amery Ice Shelf based on a novel water index

JOURNAL=Frontiers in Marine Science

VOLUME=Volume 12 - 2025

YEAR=2025

URL=https://www.frontiersin.org/journals/marine-science/articles/10.3389/fmars.2025.1476785

DOI=10.3389/fmars.2025.1476785

ISSN=2296-7745

ABSTRACT=BackgroundTraditional water indices often misclassify shadows as water, especially in polar regions. This study aims to improve water extraction accuracy by analyzing the spectral characteristics of water and shadows.MethodsA statistical analysis of the reflectance curves between red and green bands was conducted using Landsat 8 and Sentinel-2 imagery. Based on the steepness of decline in reflectance, a new water index, WI2023, was proposed. The index was validated using 10 Landsat 8 and 10 Sentinel-2 images from the Amery Ice Shelf.ResultsThe WI2023 index showed significantly improved discrimination between meltwater and shadows. Compared to NDWI and other indices, WI2023 achieved the highest accuracy when benchmarked against high-resolution Sentinel-2 data (extraction accuracy of 95.02%).ConclusionThe WI2023 index provides a robust approach for meltwater extraction in polar environments, particularly in low-latitude and low-altitude areas. It offers potential improvements in polar hydrological studies and remote sensing applications.