Assessing Two Approaches for Enhancing the Range of Simulated Scales in the E3SMv1 and the Impact on the Character of Hourly U.S. Precipitation
Our study provides a comprehensive assessment of precipitation simulated in conventional low-resolution, high-resolution, and multiscale modeling framework configurations of the Energy Exascale Earth System Model v1. Overall, we find that both high-resolution and multiscale modeling framework configurations capture more intense and less frequent precipitation on hourly and daily timescales relative to low-resolution, but in different regions and seasons. High-resolution improves the intensity over the Eastern and Northwestern U.S. during winter, while multiscale modeling framework improves the intensity over the Eastern U.S. and summer diurnal timing over the Central U.S.
Extreme precipitation events can have large impacts on society and improving the simulation of precipitation in Earth system models is essential for understanding and projecting changes in these events. Our study demonstrates that enhancing the scales that represent both the convective intensity and atmospheric dynamics of storms can lead to better representations of precipitation. However, our results indicate that these improvements occur in association with different storm types, seasons, and regions.
Improving the representation of precipitation in Earth system models is essential for understanding and projecting water cycle changes across scales. Progress has been hampered by persistent deficiencies in representing precipitation frequency, intensity, and timing in current models. Here, we analyze simulated U.S. 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 a 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 U.S. during winter, while E3SMv1-MMF improves the intensity over the Eastern U.S. and summer diurnal timing over the Central U.S. These results indicate that both methods may be needed to improve simulations of different storm types, seasons, and regions.