Initial results of fully coupled water cycle EURO-CORDEX evaluation simulations with TerrSysMP from 1989-2008

Abstract

Initial results of fully coupled water cycle EURO-CORDEX evaluationsimulations with TerrSysMP from 1989-2008Ketan Kulkarni (1,4), Jessica Keune (2,3,4), Fabian Gasper (2,4), Wendy Sharples (1,4), Bibi Naz (2,4), KlausGoergen (2,4), Stefan Kollet (2,4)(1) SimLab Terrestrial Systems, Jülich Supercomputing Centre, Research Centre Jülich, Jülich, Germany, (2) Institute of Bio-and Geosciences, Agrosphere (IBG-3), Research Centre Jülich, Jülich, Germany, (3) Meteorological Institute, BonnUniversity, Bonn, Germany, (4) Centre for High-Performance Scientific Computing in Terrestrial Systems, GeoverbundABC/J, Jülich, GermanyInteractions and feedbacks between the sub-surface including groundwater, the land surface and the atmosphereare highly relevant for weather and the climate system. However, many state of the art global and regional earthsystem models do not consider the impacts of groundwater dynamics, which are critical for the closure of thehydrological cycle on different spatial and temporal scales. In this study we implement the coupled Terrestrial Sys-tems Modelling Platform over the EURO-CORDEX domain for evaluation experiments in line with the CORDEXexperiment design in order to study how the explicit treatment of groundwater affects states and fluxes of theterrestrial water and energy cycle over a continental domain on longer simulation time spans and in relation to ex-isting uncoupled EURO-CORDEX RCM simulations. The Terrestrial Systems Modelling Platform (TerrSysMP) isa fully coupled scale-consistent numerical modelling system, currently consisting of the COSMO NWP model, theCommunity Land Model (CLM) and the ParFlow variably saturated surface and subsurface hydrological model,coupled with the external coupler OASIS3(-MCT). TerrSysMP allows for a physically-based representation oftransport processes across scales down to sub-km resolution with explicit feedbacks between the individual com-partments, including 3D groundwater dynamics and a full representation of the terrestrial hydrological cycle. Theland surface-groundwater subsystem is spun up with a 1979-1989 cyclic climatological forcing derived from ERA-Interim reanalysis until an equilibrated groundwater state is achieved. Using this as the initial conditions, the fullycoupled simulation for the period from 1989 to 2008 are carried out over the EURO-CORDEX domain at 12 kmresolution using ERA-Interim as lateral boundary forcing. COSMO physics settings are in line with the CCLMconsortium runs done for EURO-CORDEX to allow for a better comparison. The JUBE2 (Juelich BenchmarkingEnvironment) workflow engine is used to manage the complex operation of the simulations. In the analysis, wediscuss the impact of groundwater on land atmosphere feedbacks and atmospheric boundary layer properties todemonstrate the added value of the coupled simulations. Several climate indices and performance metrics are usedover PRUDENCE analysis regions in a comparison with observational data