Advances in computational power have enabled global climate models to be run at increasingly higher spatial resolution—including regionally refined-grid configurations and emerging kilometer-scale storm-resolving models. These high-resolution systems capture atmospheric and oceanic processes that are either poorly represented in traditional low-resolution models. As a result, they offer the potential to reduce mean-state biases, improve the representation of climate variability, enhance the decadal climate prediction and longer-terim projections, and help bridge weather and climate research by consistently resolving mesoscale phenomena across timescales.
Recent studies show that higher resolution improves multiple aspects of climate modeling, including more realistic precipitation distributions and extremes—a robust, cross-model feature linked to model grid spacing. My research leverages these high-resolution capabilities to investigate how fine-scale processes influence large-scale circulation and climate response, with a particular emphasis on Arctic change and its downstream impacts.
Scientific Questions
How does horizontal resolution shape the simulated mean climate, climate variability and long-term climate change?
What fine-scale processes, such as vertical motion, moisture transport, or ice–ocean-atmosphere interactions, are responsible for differences between coarse- and high-resolution model behavior?
How can storm-resolving models be leveraged to advance the research at the interface of climate dynamics and mesoscale processes?
Recent Findings
We investigate how horizontal resolution affects climate responses to Arctic sea-ice loss using CESM2.2 PAMIP-type experiments at global 110-km and Arctic-refined 14-km resolution. Both models show that sea-ice loss drives enhanced winter Arctic precipitation, but the refined-grid configuration produces a larger increase due to stronger updrafts and greater upward moisture transport. Daily precipitation variability also increases in both models, with changes more than twice as large in the refined grid, again linked to differences in vertical-motion variability. Although both resolutions capture Arctic amplification and zonal-wind deceleration, the refined model shows stronger warming and more pronounced dynamical adjustments. Together, these results highlight the importance of horizontal resolution—and the associated fine-scale vertical processes—in shaping Arctic hydroclimate and circulation responses.
Probability density functions (PDFs) of the Arctic upward ω₈₅₀, q₈₅₀, and total precipitation rate in the control simulations of the global 110-km and Arctic 14-km models. The 14-km output is regridded to the 110-km grid. Adopted from Sun et al. (2025a).
Related Collaborative Projects
Atmospheric response to anomalous ocean heat transport over western boundary currents
(Sun et al. 2025b)Sensitivity of atmospheric circulation response to aerosol perturbations across model resolutions
(ongoing; led by Dr. Xueying Zhao, NCAR)
On-going Work
- Analysis of the 3.75-km global EarthWorks model DYAMOND-1 simulation
References
Sun, L., R. Wills, C. Deser, A. Herrington, I. Simpson, M. Gervais, 2025a: Increased Model Resolution Amplifies Arctic Precipitation and Atmospheric Circulation Response to Sea-Ice Loss, J. Climate, in review. [Preprint].
Sun, L., C. Patrizio, D. Thompson and J. Hurrell, 2025b: Influence of Anomalous Ocean Heat Transport on the Extratropical Atmospheric Circulation in a High-Resolution Slab-Ocean Coupled Model, Geophys. Res. Lett., 52, e2024GL111770. [Link].
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See additional details in the Publications section.