Temporal-Statistical Analysis of Groundwater Changes and Its Relationship with Precipitation and Temperature Variables in Western Iran Using GracE-Mascon and ERA5-L and Data

Sadeghi, Hamidreza; Fathniya, Amanollah; Sharifi, Ehsan

doi:10.22111/jneh.2026.54022.2146

Temporal-Statistical Analysis of Groundwater Changes and Its Relationship with Precipitation and Temperature Variables in Western Iran Using GracE-Mascon and ERA5-L and Data

Articles in Press

Document Type : Research Article

Authors

¹ PhD student of Climatology, Geography Department, University of Razi, Kermanshah, Iran

² Associate Professor, Department of Physical Geography, University of Razi, Kermanshah, Iran

³ Assistant Professor, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany

10.22111/jneh.2026.54022.2146

Abstract

In this study, temporal variations of terrestrial water storage (LWE) in western Iran were examined using GRACE/GRACE-FO Mascon data, along with precipitation and temperature from the ERA5-Land reanalysis for 2002–2023. Area-averaged LWE, precipitation, and temperature were extracted, and monthly anomalies were calculated. Linear regression was used for trend analysis, and Pearson correlation with a 0.05 significance level assessed relationships among variables. Lag correlations with delays of zero to three months evaluated groundwater response to climatic factors. Results showed a regular seasonal LWE cycle, with near-zero or slightly positive values in winter and early spring, and strongly negative values in summer and autumn. LWE had a significant decreasing trend at all scales: about −0.8 cm per year annually and −0.8 to −1 cm per season. Precipitation and temperature showed no significant trends. At the monthly scale, correlations of LWE with precipitation and temperature were about 0.47 and −0.38; seasonally, 0.48 and −0.36, respectively, all significant. Maximum correlation with precipitation occurred at a one-month lag and with temperature at zero lag, indicating a relatively rapid groundwater response. The Mascon data showed that the significant LWE decline, despite no trend in precipitation or temperature, is mainly driven by human pressures on groundwater resources.

Keywords

Main Subjects

Climatology

References

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