Zhu et al. (2026) Precipitation trend uncertainty from product choice rivals or exceeds the magnitude of actual trends

Identification

• Journal: Communications Earth & Environment
• Year: 2026
• Date: 2026-10-27
• Authors: Shengli Zhu, Yoshihide Wada, Diego G. Miralles, Yongqiang Zhang, Chiyuan Miao, Hamza Kunhu Bangalath, wangxt1314, Hylke E. Beck
• DOI: 10.1038/s43247-026-04148-w

Research Groups

• Biological and Environmental Science and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
• Hydro-Climate Extremes Lab (H-CEL), Ghent University, Ghent, Belgium
• Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China
• State Key Laboratory of Earth Surface Processes and Disaster Risk Reduction, Faculty of Geographical Science, Beijing Normal University, Beijing, China

Short Summary

This study evaluates the reliability of long-term precipitation trends from 19 gridded products, revealing that uncertainty from product choice often rivals or exceeds the magnitude of actual trends, largely due to spatially coherent discontinuities linked to observing-system changes. This significant uncertainty propagates into critical applications, particularly in the tropics and Global South.

Objective

• To evaluate the reliability of long-term precipitation trends derived from gridded precipitation products and quantify the uncertainty introduced by product choice.

Study Configuration

• Spatial Scale: (Quasi-)global, focusing on land areas.
• Temporal Scale: Long-term, specifically evaluating trends for the period 1983–2025.

Methodology and Data

• Models used: 19 (quasi-)global gridded precipitation products.
• Data sources: Daily and monthly rain-gauge observations (for benchmarking).

Main Results

• Most gridded precipitation products exhibit spatially coherent discontinuities, primarily linked to satellite-instrument transitions in the late 1990s to early 2000s and 2014–2015.
• Only 58–64% of non-gauge-corrected products match the reference trend sign on average.
• The interquartile range of product trends is 1.1–1.9 times the reference magnitude, indicating that product choice uncertainty rivals or exceeds the actual trend magnitude.
• For 1983–2025 annual-mean trends over land, eight long-record products span and extend beyond the climate model ensemble envelope, implying observations cannot cleanly disentangle model error from observational uncertainty.

Contributions

• Quantifies the significant uncertainty in long-term precipitation trends arising from the choice of gridded precipitation product.
• Highlights the impact of observing-system changes (especially satellite transitions) on product homogeneity and trend reliability.
• Demonstrates that observational uncertainty can be as large as or larger than actual trends, complicating the disentanglement of model error from observational uncertainty in climate studies.
• Emphasizes the critical implications of this uncertainty for infrastructure design, agricultural risk management, and climate finance, particularly in vulnerable regions.

Funding

• King Abdullah University of Science and Technology (KAUST)

Citation

@article{Zhu2026Precipitation,
  author = {Zhu, Shengli and Wada, Yoshihide and Miralles, Diego G. and Zhang, Yongqiang and Miao, Chiyuan and Bangalath, Hamza Kunhu and wangxt1314 and Beck, Hylke E.},
  title = {Precipitation trend uncertainty from product choice rivals or exceeds the magnitude of actual trends},
  journal = {Communications Earth & Environment},
  year = {2026},
  doi = {10.1038/s43247-026-04148-w},
  url = {https://doi.org/10.1038/s43247-026-04148-w}
}