Assessing two approaches for enhancing the range of simulated scales in the E3SMv1 and the impact on the character of hourly US precipitation

Progress has been hampered by persistent deficiencies in representing precipitation frequency, intensity, and timing in current models. Here, we analyze simulated US precipitation in the low-resolution (LR) configuration of the Energy Exascale Earth System Model (E3SMv1) and assess the effect of two approaches to enhance the range of explicitly resolved scales: high-resolution (HR) and multiscale modeling framework (MMF), which incur similar computational expense.

Both E3SMv1-MMF and E3SMv1-HR capture more intense and less frequent precipitation on hourly and daily timescales relative to E3SMv1-LR. E3SMv1-HR improves the intensity over the Eastern and Northwestern US during winter, while E3SMv1-MMF improves the intensity over the Eastern US and summer diurnal timing over the Central US. These results indicate that both methods may be needed to improve simulations of different storm types, seasons, and regions.