The ExtremeX global climate model experiment: investigating thermodynamic and dynamic processes contributing to weather and climate extremes

Abstract. The mechanisms leading to the occurrence of extreme weather and climate events are varied complex. They generally encompass a combination dynamic thermodynamic processes, as well drivers external system, such anthropogenic greenhouse gas emissions land use change. Here we present ExtremeX multi-model intercomparison experiment, which was designed investigate contribution processes recent extremes. numerical experiments performed with three Earth system models: CESM, MIROC, EC-Earth. include control interactive atmosphere surface conditions, wherein atmospheric circulation, soil moisture, or both constrained using observation-based data. temporal evolution magnitude temperature anomalies during heatwaves represented in atmosphere. However, mean climatological biases precipitation not greatly reduced any due persistent newly introduced biases. This highlights importance error compensations tuning standard model versions. To show one possible application, is used identify main warm spells. results reveal that circulation patterns moisture conditions substantially contribute these events. Soil effects particularly important tropics, monsoon areas, Great Plains United States, whereas major other midlatitude high-latitude regions.