Meng et al. (2026) Effectiveness of multi-source merged soil moisture products using different triple collocation methods: A comprehensive assessment incorporating spatial similarity evaluation framework

Identification

• Journal: Remote Sensing of Environment
• Year: 2026
• Date: 2026-10-07
• Authors: CAO Meng, Min Chen, Jeffrey P. Walker
• DOI: 10.1016/j.rse.2026.115715

Research Groups

Department of Civil and Environmental Engineering, Monash University, Vic, Clayton, 3800, Australia
College of Hydraulic Engineering, China Three Gorges University, Yichang, 443002, China
Engineering Research Center of Eco-environment in Three Gorges Reservoir Region, Ministry of Education, Yichang, 443002, China

Short Summary

This study evaluates the effectiveness of multi-source merged soil moisture products using different triple collocation methods and introduces a spatial evaluation framework based on the Structural Similarity Index (SSIM). The results show that two-dimensional TC merging method with local spatial errors (TC2Dlocal) outperforms other approaches in capturing temporal dynamics and spatial patterns of soil moisture over China.

Objective

• Evaluate the performance of multi-source merged soil moisture products using different triple collocation methods.
• Assess the effectiveness of a spatial evaluation framework based on SSIM for evaluating soil moisture products.

Study Configuration

• Spatial Scale: Regional scale, covering China.
• Temporal Scale: Long-term (temporal dynamics and spatial patterns).

Methodology and Data

• Models used: Triple collocation methods: traditional TC (TCtemporal), global two-dimensional TC (TC2D), and modified TC with local spatial errors (TC2Dlocal).
• Data sources: Soil moisture products from SMAP, ASCAT, ERA5-Land; validation data from International Soil Moisture Network (ISMN), agricultural stations, and China Meteorological Administration Land Data Assimilation System (CLDAS).

Main Results

• The two-dimensional TC merging methods outperformed the traditional TC method in capturing temporal dynamics and spatial patterns of soil moisture.
• TC2Dlocal showed better performance than TC_2D in western China with more sophisticated environmental conditions.

Contributions

• This study demonstrates the effectiveness of two-dimensional TC for merging multi-source soil moisture products, particularly TC2Dlocal for environmentally heterogeneous regions.
• The spatial similarity evaluation framework provides a new perspective and additional insights into the performance of soil moisture products.

Funding

• This research was funded by the Engineering Research Center of Eco-environment in Three Gorges Reservoir Region, Ministry of Education, Yichang, 443002, China.

Citation

@article{Meng2026Effectiveness,
  author = {Meng, CAO and Chen, Min and Walker, Jeffrey P.},
  title = {Effectiveness of multi-source merged soil moisture products using different triple collocation methods: A comprehensive assessment incorporating spatial similarity evaluation framework},
  journal = {Remote Sensing of Environment},
  year = {2026},
  doi = {10.1016/j.rse.2026.115715},
  url = {https://doi.org/10.1016/j.rse.2026.115715}
}