Code for "Resolution Controls on SST–Precipitation Coupling in Western Boundary Currents"

Code and data to reproduce the main Figures in "Resolution Controls on SST–Precipitation Coupling in Western Boundary Currents" Authors Eduardo Moreno-Chamarro, Dian Putrasahan, Marco Giorgetta, Sarah M. Kang Abstrat Western Boundary Currents (WBCs) are key regions of intense air–sea interactions, through which the ocean can influence atmospheric variability. Recent observational and modeling work has revealed a robust local covariability between sea surface temperature (SST) anomalies and precipitation along WBCs; however, this signal appears only in mesoscale-resolving models, pointing to a resolution-sensitive coupling whose origins remain poorly understood. Here, we provide the first systematic, cross-model assessment of how oceanic and atmospheric horizontal resolution, mesoscale representation, and convective parameterization shape SST–precipitation covariability along the Gulf Stream, Kuroshio, Agulhas, and Brazil currents. Using a coordinated hierarchy of ICON and EC-Earth3P simulations with grid scales spanning from about 100 km to 10 km, either parameterizing or simulating convection explicitly, complementary atmosphere-only sensitivity experiments with mesoscale-resolving and smoothed SSTs, and the CMIP6 ensemble, we quantify how model design controls both the strength and spatial structure of the coupling. We show that mesoscale ocean variability is essential for ensuring realistic, localized precipitation responses, but that high resolution alone does not guarantee complete realism. Overly broad coupling or muted responses emerge at very high ocean resolutions or if the atmospheric convection treatment is inconsistent with the model’s resolution. These results illustrate why current models diverge in WBC-related precipitation variability and outline the coordinated advances in resolution–physics required for improved air–sea coupling in next-generation climate simulations.