Bias in CMIP6 historical U.S. severe convective environments driven by
bias in mean-state near-surface moist static energy
Abstract
This work evaluates how well Coupled Model Intercomparison Project 6
(CMIP6) models reproduce the climatology of North American SCS
environments in ERA5 reanalysis and examines what drives biases across
models. Biases in Springtime SCS environments vary widely in magnitude
and spatial pattern, but most models do well in reproducing the
climatological pattern and a few also reproduce the overall magnitude.
SCS bias is driven by bias in extreme CAPE. This bias is ultimately
found to be driven by bias in mean-state near-surface moist static
energy (MSE), indicating that the SCS environments depend strongly on
the near-surface mean state. Results are broadly similar to Spring
across all seasons, particularly Summer. Biases differ strongly across
parent models but weakly across child models of the same parent. These
outcomes help identify models well-suited for studying climate effects
on SCS environments and also provide a foundation for improving model
performance in the future.