An updated non-intrusive, multi-scale, and flexible coupling interface in WRF 4.6.0

Abstract. The Weather Research and Forecasting (WRF) model has been widely used for various applications, especially for solving mesoscale atmospheric dynamics. Its high-order numerical schemes and nesting capability enable high spatial resolution. However, a growing number of applications are demanding more realistic simulations through the incorporation of coupling with new model compartments and an increase in the complexity of the processes considered in the model (e.g., ocean, surface gravity wave, land surface, and chemistry). The present paper details the development and the functionalities of the coupling interface we implemented in WRF. It uses the Ocean–Atmosphere–Sea–Ice–Soil Model Coupling Toolkit (OASIS3-MCT) coupler, which has the advantage of being non-intrusive, efficient, and very flexible to use. OASIS3-MCT has already been implemented in many climate and regional models. This coupling interface is designed with the following baselines: (1) it is structured with a two-level design through two modules: a general coupling module and a coupler-specific module, allowing for easy additions of other couplers if required; (2) variable exchange, coupling frequency, and any potential time and grid transformations are controlled through an external text file, offering great flexibility; and (3) the concepts of external domains and a coupling mask are introduced to facilitate the exchange of fields to/from multiple sources (different models, fields from different models/grids/zooms, etc.). Finally, two examples of applications of ocean–atmosphere coupling are proposed. The first is related to the impact of ocean surface current feedback to the atmospheric boundary layer, and the second concerns the coupling of surface gravity waves with the atmospheric surface layer.