Getirana et al. (2025) Inconsistencies in GRACE‐Based Groundwater Storage Estimation—A Call for a Proper Use of Land Surface Models

⚠️ Warning: This summary was generated from the abstract only, as the full text was not available.

Identification

• Journal: Geophysical Research Letters
• Year: 2025
• Date: 2025-09-28
• Authors: Augusto Getirana, Sujay V. Kumar, Matthew Rodell
• DOI: 10.1029/2025gl119197

Research Groups

Not specified in the abstract.

Short Summary

This comment critically examines the common practice of estimating groundwater storage anomalies by subtracting land surface model components from GRACE terrestrial water storage, highlighting implicit assumptions and structural challenges due to model simplifications. It advocates for careful interpretation and more sophisticated methods in hydrological analyses.

Objective

• To examine the assumptions, semantic, and structural challenges embedded in the common practice of estimating groundwater storage (GWS) anomalies from Gravity Recovery and Climate Experiment (GRACE) terrestrial water storage (TWS) anomalies by subtracting land surface model (LSM) derived components.

Study Configuration

• Spatial Scale: Not specified; the comment addresses a general methodological practice.
• Temporal Scale: Not specified; the comment addresses a general methodological practice.

Methodology and Data

• Models used: The paper discusses the use of Land Surface Models (LSMs) in the context of the criticized methodology.
• Data sources: The paper discusses the use of Gravity Recovery and Climate Experiment (GRACE) terrestrial water storage (TWS) anomalies in the context of the criticized methodology.

Main Results

• The common method of estimating GWS anomalies by subtracting LSM-derived components from GRACE TWS anomalies implicitly assumes that LSMs account for all non-groundwater storages within distinct, physically meaningful compartments.
• This approach is fraught with assumptions, semantic, and structural challenges stemming from model simplifications and conventions.
• Users of this method are advised to carefully consider the consequences of these model simplifications on their results.
• The paper advocates for more sophisticated methods, including data assimilation and models that represent physical hydrological processes more completely, to improve GWS estimation.

Contributions

• Provides a critical examination of a widely adopted hydrological practice for estimating groundwater storage from GRACE data.
• Highlights the often-overlooked implicit assumptions and structural limitations inherent in using land surface models to partition terrestrial water storage.
• Encourages a more nuanced interpretation of results derived from this method and advocates for the adoption of more robust and physically complete modeling approaches in hydrology.

Funding

Not specified in the abstract.

Citation

@article{Getirana2025Inconsistencies,
  author = {Getirana, Augusto and Kumar, Sujay V. and Rodell, Matthew},
  title = {Inconsistencies in GRACE‐Based Groundwater Storage Estimation—A Call for a Proper Use of Land Surface Models},
  journal = {Geophysical Research Letters},
  year = {2025},
  doi = {10.1029/2025gl119197},
  url = {https://doi.org/10.1029/2025gl119197}
}