Qi et al. (2025) MODIS-Landsat fusion reveals two-decade 8-day lake dynamics with critical intra-annual regime shifts

Identification

• Journal: Journal of Hydrology
• Year: 2025
• Date: 2025-11-30
• Authors: Tianci Qi, Xiangqian Li, Hongtao Duan, Wenping Yuan
• DOI: 10.1016/j.jhydrol.2025.134702

Research Groups

• State Key Laboratory of Lake and Watershed Science for Water Security, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, China.
• College of Urban and Environmental Sciences, Shihezi University, Xinjiang, China.
• Agricultural College, Shihezi University, Xinjiang, China.
• Sino-French Institute for Earth System Science, College of Urban and Environmental Sciences, Peking University, Beijing, China.

Short Summary

The study reconstructs 8-day resolution dynamics for lakes and reservoirs in southern China from 2001 to 2020 using MODIS-Landsat data fusion. It reveals that high-frequency intra-annual variations are critical for accurate carbon budget estimates, often offsetting or equaling the impact of long-term interannual trends.

Objective

• To develop a high-temporal-resolution (8-day) reconstruction of open-water areas for inland water bodies (> 0.1 km²) to better understand intra-annual regime shifts and their implications for global change assessments.

Study Configuration

• Spatial Scale: Southern China (all water bodies exceeding 0.1 km²).
• Temporal Scale: 20-year period (2001–2020) at an 8-day temporal resolution.

Methodology and Data

• Models used: Adaptive OTSU threshold approach applied to fused remote sensing indices.
• Data sources: MODIS (high temporal resolution) and Landsat (high spatial resolution) satellite imagery fusion; lake level variation data for validation.

Main Results

• Classification Accuracy: Achieved an overall accuracy of 94.43% with a Kappa coefficient of 0.90.
• Interannual Trends: Natural lakes decreased in area by 55.92 km²/yr, while reservoirs increased by 178.80 km²/yr.
• Intra-annual Dynamics: Approximately 87% of studied lakes showed significant intra-annual variations (> 10% of total area), representing 25% and 15% of total water areas for natural lakes and reservoirs, respectively.
• Carbon Impact: The influence of intra-annual area fluctuations on lake CO₂ emissions was found to be comparable to, or even capable of offsetting, the impacts of long-term interannual permanent water trends.

Contributions

• Developed a novel framework for high-temporal-resolution lake monitoring by bridging the gap between MODIS and Landsat data constraints.
• Quantified the magnitude of intra-annual lake dynamics across a large geographic region, demonstrating that low-frequency sampling significantly underestimates the variability of lake ecosystems and their role in the global carbon cycle.

Funding

• Not specified in the provided text.

Citation

@article{Qi2025MODISLandsat,
  author = {Qi, Tianci and Li, Xiangqian and Duan, Hongtao and Yuan, Wenping},
  title = {MODIS-Landsat fusion reveals two-decade 8-day lake dynamics with critical intra-annual regime shifts},
  journal = {Journal of Hydrology},
  year = {2025},
  doi = {10.1016/j.jhydrol.2025.134702},
  url = {https://doi.org/10.1016/j.jhydrol.2025.134702}
}

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