Characteristics of the Stratospheric Tropical Circulation of the Energy Exascale Earth System Model E3SMv2

The Energy Exascale Earth System Model version 2 (E3SMv2) was publicly released by the Department of Energy (DoE) in September 2021. An important component of the model validation were historical climate simulations that followed the protocols of the Coupled Model Intercomparison Project Phase 6 (CMIP6). In particular, five historical ensemble members were recently released, and 16 additional ensemble members will soon become available as part of an E3SMv2 Large Ensemble (LE). The paper sheds light on the characteristics of the E3SMv2 CMIP6 stratospheric circulation which has not yet been documented in the literature. Particular attention is paid to the tropical stratosphere which includes the so-called water vapor tape recorder and the Quasi-Biennial Oscillation. In addition, the general circulation and its variability are briefly described to reveal E3SMv2’s strengths and weaknesses. We compare E3SMv2’s circulation to observations and ERA5 reanalysis data. Furthermore, selected comparisons to the predecessor version E3SMv1 as well as other CMIP6 models are provided to put the results into context. The analysis informs the DoE Sandia National Laboratories project CLDERA which uses the Mt. Pinatubo volcanic eruption for climate attribution studies.