Guidance on Selecting a Reference Year for Groundwater Initialization in Regional Models

[Tom jerry]

Hello everyone,

I am currently conducting regional groundwater modeling using ParFlow. The model has completed a steady-state groundwater field initialization, derived from long-term average precipitation minus evapotranspiration (P-E), resulting in groundwater pressure heads and storage that reflect a long-term hydrologic equilibrium. The next step is to select a reference year of meteorological forcing to perform a transient coupled spin-up with the land surface model, providing physically consistent initial conditions for the groundwater system.  

My research focus is on the groundwater system itself: based on this initialization, how can a reference year be selected so that the groundwater pressure head and storage fields are both representative of the long-term average hydrologic climate and suitable as a starting point for subsequent fully transient simulations?  

I would greatly appreciate any experience, insights, or guidance from the community on best practices for reference year selection and initialization in regional groundwater modeling.

Best regards,

YD Dai