Long-term dense Landsat observations reveal detailed waterbody dynamics and temporal changes of the size-abundance relationship

Abstract

Study region: Surface water bodies in Hunan Province, China. Study focus:: Surface water bodies (WB) are important for agriculture, aquiculture, and aquatic and terrestrial ecosystems, yet monitoring and understanding the spatiotemporal dynamics of water bodies over large areas remain a major challenge. This study used all the available Landsat images and the Google Earth Engine (GEE) to map and analyze annual changes of all water bodies (>0.001 km2) in Hunan Province, China, from 1987 to 2020. New hydrological insights for the region:: A total of 76,928 WBs were detected with a total area of 4181.14 km2 (both were averages during the study period) with an interannual variability of − 117 and − 20.05 km2 year-1, respectively. Surface areas of small (0.001–1 km2), medium (1–50 km2), and large (>50 km2) WBs changed at various rates and directions. The size-abundance relationship of WBs followed the power scaling law with a positive trend in the scaling exponent, implying the fraction of small WB number has decreased over the past three decades. The temporal change of the size-abundance relationship, reflects the strong and dynamic imprints of both human activities and regional climate change. Future research should strive to understand the temporal change of the size-abundance relationship of WBs as it is important for water resources management and estimating the temporal changes of greenhouse gas fluxes from WBs over large areas.

Keywords

• Water body detection
• Dynamics
• Size-abundance
• Spatiotemporal variability