Global map from the study.
Distribution of annual-mean precipitation in simulation with the Nonhydrostatic ICosahedral Atmospheric Model (NICAM) at 14 km horizontal resolution, with updated parameterizations for the fall velocity of rain, snow, and cloud ice. The right panel shows the zonal mean, with observations, for comparison, in black. The updated microphysical parameters lead to a simulation with substantially improved precipitation simulations. Credit: Takasuka et al. [2024], Figure 9d
Editors’ Highlights are summaries of recent papers by AGU’s journal editors.
Source: Journal of Advances in Modeling Earth Systems

In a new study, Takasuka et al. [2024] improve the Nonhydrostatic ICosahedral Atmospheric Model (NICAM) by implementing a turbulent mixing parameterization akin to those used in large-eddy simulations, coupled with re-tuned parameterizations of the fall velocities of rain, snow, and cloud ice in its microphysics parameterization. This update to NICAM at 14-kilometer resolution simultaneously yields more accurate simulations of tropical variability, such as the intraseasonal Madden-Julian Oscillation, and improved simulations of climate statistics, such as the annual-mean precipitation rate. Notably, the pervasive double Inter-Tropical Convergence Zone (ITCZ) bias in climate models is substantially reduced.

While these advances mark significant progress, challenges persist, particularly with the accurate representation of low clouds—a feature beyond the scope of 14-kilometer resolution. Insights from this study are expected to inform the development of models at kilometer-scale resolution, for which the repeated long integrations carried out here are not yet computationally feasible.

Citation: Takasuka, D., Kodama, C., Suematsu, T., Ohno, T., Yamada, Y., Seiki, T., et al. (2024). How can we improve the seamless representation of climatological statistics and weather toward reliable global K-scale climate simulations? Journal of Advances in Modeling Earth Systems, 16, e2023MS003701. https://doi.org/10.1029/2023MS003701

—Tapio Schneider, Editor, JAMES

Text © 2024. The authors. CC BY-NC-ND 3.0
Except where otherwise noted, images are subject to copyright. Any reuse without express permission from the copyright owner is prohibited.