ECOMIP: The EarthCARE-ORCESTRA Model Intercomparison Project

Abstract. This study proposes the EarthCARE-ORCESTRA Model Intercomparison Project (ECOMIP), a framework for evaluating various range of atmospheric models, including global or regional km-scale models using observations from the EarthCARE satellite and the ORCESTRA (Organized Convection and EarthCARE Studies over the Tropical Atlantic) field campaign. The goal of ECOMIP is not to rank model performance but to provide a clear path to improve models by considering how new satellite observations, combined with in situ measurements and satellite simulators, can constrain cloud microphysics, precipitation, and convective dynamics. This paper presents the protocol for Phase 1 of the ECOMIP framework, consisting of 2-day simulations designed for comparison with EarthCARE and ORCESTRA observations. As a first examination of the model intercomparison, NICAM, ICON, and IFS simulations are evaluated with EarthCARE observations during the satellite overpass over the ORCESTRA domain on 3 September 2024. Along the EarthCARE track, the occurrence of a mesoscale convective system and Southern Hemisphere cirrus clouds is captured in both simulations. The three models exhibit different convective organization characteristics. NICAM and IFS tend to produce larger and more coherent convective systems, whereas ICON shows more scattered convective cores. Although conclusions from a single EarthCARE frame cannot be generalized, these results provide an example of model-dependent characteristics and demonstrate the potential of the proposed protocol for improving our understanding through the analysis of a larger number of EarthCARE cases and datasets in future studies. We also present the comprehensive framework of ECOMIP after Phase 1, including statistical free-run simulations and observationally constrained parameter-sensitivity experiments.