Yan et al. (2026) Decadal surge of water-surface solar in China's Yangtze Delta: A high-fidelity SAR-optical fusion inventory (2015–2024)

Identification

• Journal: Earth system science data
• Year: 2026
• Date: 2026-08-24
• Authors: Yue Yan, Xin Jiang, Sihuan Wei, Yubin Jin, Xinyu Zou, Junwei Liu, Yaotong Cai, Jianhuai Ye, Zhilin Guo, Zhenzhong Zeng
• DOI: 10.5194/essd-18-5951-2026

Research Groups

• School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
• Zhejiang Key Laboratory of Industrial Intelligence and Digital Twin, Eastern Institute of Technology, Ningbo, Zhejiang, China
• Department of Building Environment and Energy Engineering, The Hong Kong Polytechnic University, Kowloon, Hong Kong SAR, China
• International Centre of Urban Energy Nexus, The Hong Kong Polytechnic University, Kowloon, Hong Kong SAR, China

Short Summary

This study presents a high-fidelity water-surface photovoltaics (WPV) inventory for the Yangtze River Delta region in China from 2015 to 2024. Using a multi-sensor fusion framework combining Sentinel-1 Synthetic Aperture Radar and Sentinel-2 optical imagery, the authors developed a random forest classifier to generate annual WPV maps with an overall accuracy of 97.3% and a Cohen's kappa coefficient of 0.94.

Objective

• Investigate the spatial dynamics and scalability of water-surface photovoltaics (WPV) in the Yangtze River Delta region.
• Develop a high-fidelity WPV inventory for the study area from 2015 to 2024.

Study Configuration

• Spatial Scale: The study focuses on the Yangtze River Delta region, which is located in eastern China along the lower reaches of the Yangtze River.
• Temporal Scale: The study covers a period of 10 years (2015-2024).

Methodology and Data

• Models used: Random Forest classifier implemented with the smileRandomForest algorithm in Google Earth Engine (GEE).
• Data sources: Sentinel-1 Synthetic Aperture Radar, Sentinel-2 Multispectral Instrument imagery, and water body datasets (HydroLAKES, GRanD, GOODD, and GeoDAR).

Main Results

• The WPV inventory covers 401 validated projects with a cumulative area of 145.4 km^2 by 2024.
• The results reveal rapid expansion from 17.4 km^2 in 2015 to 145.4 km^2 in 2024, with 87% of WPV area deployed on natural lakes.
• A marked shift in dominance from Jiangsu to Anhui is observed.

Contributions

• This study provides a high-fidelity WPV inventory for the Yangtze River Delta region, which can be used for understanding spatiotemporal growth dynamics and policy-relevant deployment patterns.
• The results highlight the importance of considering water-surface photovoltaics as a promising alternative to conventional PV systems.

Funding

• This research was supported by the National Natural Science Foundation of China (Grant No. 52179221) and the Guangdong Provincial Key Laboratory of Urban Informatics (Grant No. 2021A0505010003).

Citation

@article{Yan2026Decadal,
  author = {Yan, Yue and Jiang, Xin and Wei, Sihuan and Jin, Yubin and Zou, Xinyu and Liu, Junwei and Cai, Yaotong and Ye, Jianhuai and Guo, Zhilin and Zeng, Zhenzhong},
  title = {Decadal surge of water-surface solar in China's Yangtze Delta: A high-fidelity SAR-optical fusion inventory (2015–2024)},
  journal = {Earth system science data},
  year = {2026},
  doi = {10.5194/essd-18-5951-2026},
  url = {https://doi.org/10.5194/essd-18-5951-2026}
}