The Community Earth System Model Version 2 (CESM2)

In addition, an evaluation of a pair of CESM2 long preindustrial control and historical ensemble simulations is presented. These simulations were performed using the nominal 1 degrees horizontal resolution configuration of the coupled model with both the "low-top" (40 km, with limited chemistry) and "high-top" (130 km, with comprehensive chemistry) versions of the atmospheric component.

CESM2 contains many substantial science and infrastructure improvements and new capabilities since its previous major release, CESM1, resulting in improved historical simulations in comparison to CESM1 and available observations. These include major reductions in low-latitude precipitation and shortwave cloud forcing biases; better representation of the Madden-Julian Oscillation; better El Nino-Southern Oscillation-related teleconnections; and a global land carbon accumulation trend that agrees well with observationally based estimates.