Response of the surface climate to different groundwater options using the WRF model

An analysis of the sensitivity of different surface model options in the WRF model was performed. The main goal is to investigate the transition from wet to dry regimes through the analysis of the soil moisture–temperature, and soil moisture–precipitation interactions; and explore the response of the surface climate to different model options. Four simulations with the WRF model were carried out with different land surface model schemes for the 2004-2006 period, driven by ERA5 reanalysis. The WRF model was used for the simulations over the European domain with a horizontal resolution of 0.11 degrees and 50 vertical levels, which follows the CORDEX guidelines. These simulations rely on the same physical parameterisations with different surface model options. For the first experiment, the Noah land surface model was used. For the remaining simulations, the Noah-MP (multi-physics) land surface model was used with different runoff and groundwater options: (1) original surface and subsurface runoff (free drainage), (2) TOPMODEL with groundwater and (3) Miguez-Macho & Fan groundwater scheme.

An extensive evaluation of all simulations against observations was performed, which is an important step to determine the quality of the simulations. In this way, precipitation, maximum and minimum temperatures from all simulations were compared against observations. The new version of the Europe‐wide E‐OBS temperature and precipitation data set was used to compare with the output of the simulations performed. This dataset has a regular grid with 0.1o spatial resolution. The evaluation of temperature and precipitation showed that the 1st and 4th setup have the best agreement against observations. Additionally, for each WRF experiment, the land energy balance and the land water balance were computed. These results showed some differences between simulations, in particular for the land water balance. Additional analysis are being carried out to determine the impact of different groundwater options of LSMs in surface climate.

 

Acknowledgements. The authors wish to acknowledge the LEADING (PTDC/CTA-MET/28914/2017) project funded by FCT. The authors would like to acknowledge the financial support FCT through project UIDB/50019/2020 – Instituto Dom Luiz.