Project: Seasonal Water Resources Management for Semiarid Areas: Regionalized Global Data and Transfer to Practise - GRoW-SaWaM (BMBF): The SaWaM-Project, which is funded by the German Federal Ministry of Education and Research (BMBF) within the "Water as a global Resource (GRoW)“ initiative, aims at the development of methods and products for improving the water management in semi-arid regions. The methodological core of the project is a model chain, where global hydrometeorological information is first adapted towards five different study regions in Brazil (Rio São Francisco Basin), Iran (Karun Basin), Sudan and Ethiopia (Tekeze-Atbara and Blue Nile Basins), Ecuador and Peru (Catamayo-Chira Basin) and West-Africa (Niger and Volta Basins). Special focus is put on the application of seasonal hydrometeorological forecasts, which give information about the precipitation or temperature to be expected during the coming months. The regionalized information is then used as driving data for hydrological and ecosystem models, which allow for the description of water-management-related parameters and aspects both in the past, but also for the coming months. Further information can be found at http://grow-sawam.org/. Summary: While climate information from General Circulation Models (GCMs) are usually too coarse for climate impact modelers or decision makers from various disciplines (e.g., hydrology, agriculture), Regional Climate Models (RCMs) and Regional Earth System Models (RESMs) provide feasible solutions for downscaling GCM output to finer spatiotemporal scales. However, it is well known that the model performance depends largely on the choice of the physical parameterization schemes, but optimal configurations may vary from region to region. Besides land-surface processes, the most crucial processes to be parameterized in ESMs include radiation (RA), cumulus convection (CU), cloud microphysics (MP), and planetary boundary layer (PBL), partly with complex interactions. Before conducting long-term climate simulations, it is therefore indispensable to identify a suitable combination of physics parameterization schemes for these processes. Using the European Centre for Medium-Range Weather Forecasts (ECMWF) reanalysis product ERA-Interim as lateral boundary conditions, we derived an ensemble of 16 physics parameterization runs for a larger domain in Northern sub-Saharan Africa (NSSA), northwards of the equator, using two different CU-, MP-, PBL-, and RA schemes, respectively, using the Weather Research and Forecasting (WRF) model (Version v3.9) for the period 2006-2010 in a resolution of 0.1 degree horizontal resolution. Conclusions about suitable physical parameterization schemes may vary within the study area. We therefore want to stimulate the development of own performance evaluation studies for climate simulations or subsequent impact studies over specific (sub-)regions in NSSA. For this reason, selected climate surface variables of the physics ensemble (i.e. the 16 experiments from 2006-2010) are provided. For more information about the setup of the experiments, please see: Laux et al., 2021: A high-resolution regional climate model physics ensemble for Northern sub-Saharan Africa. Frontiers in Earth Science (under revision).
