Qin et al. (2026) Gain–phase characteristics of groundwater responses to barometric pressure: interpreting subsurface confinement in layered systems

Identification

• Journal: Journal of Hydrology
• Year: 2026
• Date: 2026-03-11
• Authors: Zixuan Qin, Jian Guo, Peter John Cleall, Qiang Xu, John A. Cherry, Beth L. Parker
• DOI: 10.1016/j.jhydrol.2026.135296

Research Groups

• State Key Laboratory of Geo-hazard Prevention and Geo-environment Protection, Chengdu University of Technology, Chengdu, China
• Cardiff University School of Engineering, Cardiff University, Cardiff, Wales, UK
• Morwick G360 Groundwater Research Institute, College of Engineering & Physical Sciences, University of Guelph, Guelph, Canada

Short Summary

This study applies frequency-domain barometric response functions (BRF) to analyze groundwater response to atmospheric pressure in a layered aquifer. It demonstrates the utility of BRF analysis for interpreting pressure transmission and confinement in vertically heterogeneous aquifers, revealing distinct gain-phase relationships for different confinement types.

Objective

• To apply frequency-domain barometric response functions (BRF) to analyze groundwater response to atmospheric pressure for interpreting subsurface confinement in vertically heterogeneous, layered aquifer systems.

Study Configuration

• Spatial Scale: Borehole-scale investigation within a layered aquifer using a six-port Continuous Multichannel Tubing (CMT) system.
• Temporal Scale: Long-term monitoring of groundwater levels, barometric pressure, and precipitation.

Methodology and Data

• Models used: Cross-correlation, Fast Fourier Transform (FFT), and Barometric Response Functions (BRF) methods.
• Data sources: Long-term groundwater level, barometric pressure, and precipitation data collected from a six-port Continuous Multichannel Tubing (CMT) system installed in a layered aquifer.

Main Results

• Time- and frequency-domain analyses revealed pronounced lithology-controlled differences in groundwater responses.
• Ports screened in sandstone units exhibited stronger barometric signals and shorter response lags compared to mudstone-adjacent ports, which showed attenuated responses.
• An upper sandstone unit (above mudstone) displayed a negative gain-phase co-variation, characteristic of unconfined systems.
• A lower sandstone unit (below mudstone) exhibited a positive gain-phase relationship, indicative of functional confinement.
• The study highlights the effectiveness of BRF analysis for interpreting pressure transmission and confinement in vertically heterogeneous aquifers.

Contributions

• Introduces and validates the application of frequency-domain Barometric Response Functions (BRF) as a robust method for identifying and interpreting aquifer confinement and pressure transmission in complex, vertically heterogeneous layered systems.
• Offers a non-invasive, continuous monitoring approach to characterize aquifer confinement, overcoming limitations of conventional methods such as subjectivity, high costs, and disturbance.
• Provides a novel interpretation of gain-phase relationships in BRF analysis to distinguish between unconfined and functionally confined conditions in layered aquifers.

Funding

• Not specified in the provided text.

Citation

@article{Qin2026Gainphase,
  author = {Qin, Zixuan and Guo, Jian and Cleall, Peter John and Xu, Qiang and Cherry, John A. and Parker, Beth L.},
  title = {Gain–phase characteristics of groundwater responses to barometric pressure: interpreting subsurface confinement in layered systems},
  journal = {Journal of Hydrology},
  year = {2026},
  doi = {10.1016/j.jhydrol.2026.135296},
  url = {https://doi.org/10.1016/j.jhydrol.2026.135296}
}