Will Increasing Climate Model Resolution Be Beneficial for ENSO Simulation?

Abstract

Increasing climate model resolution offers multifaceted benefits, such as improving modeled tropical cyclones. However, the extent to which it benefits El Niño‐Southern Oscillation (ENSO) simulation remains unknown. Here, comprehensive information on the sensitivity of ENSO performance to various resolutions is provided, based on a multi‐model and multi‐resolution ensemble of global coupled models. Overall, the reduced model biases of the equatorial sea surface temperature (SST) and precipitation mean state in higher‐resolution models may be attributed to increased oceanic resolution, and thus, better resolved eddy‐driven heat transport. ENSO spatial patterns were reproduced clearer in the eddy‐present models, likely due to the improved mean state and associated surface thermodynamic feedback. However, increasing atmospheric resolution alone deteriorates ENSO asymmetry, which may be due to the degradation of nonlinear atmospheric feedback. It remains challenging to alleviate the SST−shortwave‐flux feedback bias, which is a major source of too‐weak net heat flux feedback, irrespective of model resolution.

On the future zonal contrasts of equatorial Pacific climate: Perspectives from Observations, Simulations, and Theories

“…A simple atmosphere-ocean model with a prescribed climatology responded to the historical increase in greenhouse gases with an enhanced zonal SST gradient when the observed climatology was imposed, but a reduced gradient when the CMIP5 multi-model mean climatology was imposed 27 . Climate models with higher oceanic resolution appear to simulate more accurate equatorial Pacific SST and ENSO patterns, but the increasing atmospheric resolution still results in persistent errors in radiative flux feedbacks 192 . This emphasizes the need for the climate community to invest in reducing the tropical SST and circulation biases endemic to multiple generations of CMIP class models.…”

Storylines of Maritime Continent dry period precipitation changes under global warming

“…From previous phases of the CMIP, a gradual improvement in representing the mean state of the tropical Pacific SST has been found (Bellenger et al 2014, Jiang et al 2021, with improved associated rainfall teleconnections (Grose et al 2020). Recent studies suggest that moving towards high resolution model simulations with resolved ocean mesoscale eddies could further reduce the remaining biases in the tropical Pacific SST (Wengel et al 2021, Liu et al 2022. Such improvements could potentially constrain the plausibility of some of the storylines described here.…”

Rectifying low-frequency variability in future climate sea surface temperature simulations: are corrections for extreme change scenarios realistic?

“…We analyze the monthly SST over the Niño 3.4 region (5 • N-5 • S, 120 • W-170 • W). We use SST over a 100-latitude × 200-longitude grids of UHR-CESM model for PD as representative of the current climate/observations, while simulations for 2×CO 2 and 4×CO 2 forcings considered representative of plausible futures [16,20]. For a comprehensive comparison, we select eight models as listed in table S1 (in the supplementary material) from the CMIP6 database that provide the data with 2×CO 2 and 4×CO 2 forcings.…”

“…Higher resolution of climate models are shown to simulate reduced surface warm bias over the tropical South Atlantic and cold bias in the North Atlantic compared to the lower resolution of climate models [19]. Another study shows a reduction of biases in SST and precipitation simulations in the equatorial Pacific [20]. In hydrological studies such as on the analysis of extreme rainfall events, high-resolution climate models or regional climate models (RCMs) are preferred [21].…”