MARC

LEADER 00000nab a2200000uu 4500
001 3253520121
003 UK-CbPIL
022 |a 1991-962X 
022 |a 1991-9603 
024 7 |a 10.5194/gmd-18-6255-2025  |2 doi 
035 |a 3253520121 
045 2 |b d20250101  |b d20251231 
084 |a 123629  |2 nlm 
100 1 |a Eirund, Gesa K.  |u Environmental Physics, Institute of Biogeochemistry and Pollutant Dynamics, Zurich, ETH Zurich, Switzerland 
245 1 |a ROMSOC: a regional atmosphere–ocean coupled model for CPU–GPU hybrid system architectures 
260 |b Copernicus GmbH  |c 2025 
513 |a Journal Article 
520 3 |a Recent years have seen significant efforts to refine the horizontal resolutions of global and regional climate models to the kilometer scale. This refinement aims to better resolve atmospheric and oceanic mesoscale processes, thereby improving the fidelity of simulations. However, these high-resolution simulations are computationally demanding, often necessitating trade-offs between resolution and simulated timescale. A key challenge is that many existing models are designed to run on central processing units (CPUs) alone, limiting their ability to leverage the full computational power of modern supercomputers, which feature hybrid architectures with both CPUs and graphics processing units (GPUs). In this study, we introduce the newest model version of ROMSOC, a recently developed regional coupled atmosphere–ocean model. This new model version integrates the Regional Oceanic Modeling System (ROMS) in its original CPU-based configuration with the Consortium for Small-Scale Modeling (COSMO) model (v5.12), which can utilize GPU accelerators on heterogeneous system architectures. The combination efficiently exploits the hybrid CPU–GPU architecture of the Piz Daint supercomputer at the Swiss National Supercomputing Centre (CSCS), achieving a speed-up of up to 6 times compared to a CPU-only version with the same number of nodes. We evaluated the model using a configuration focused on the northeast Pacific, where ROMS covers the entire Pacific Ocean with a telescopic grid, providing full-ocean mesoscale-resolving refinement in the California Current System (CalCS; 4 km resolution). Meanwhile, COSMO covers most of the northeast Pacific at a 7 km resolution. This configuration was run in hindcast mode for the years 2010–2021, examining the roles of different modes of air–sea coupling at the mesoscale, including thermodynamical coupling (associated with heat fluxes) and mechanical coupling (associated with wind stress and surface ocean currents). Our evaluation indicates that the hindcast generally agrees well with observations and reanalyses. Notably, large-scale sea surface temperature (SST) patterns and coastal upwelling are well-represented, but SSTs show a small cold bias, resulting from wind forcing that is too strong and biases in the radiative forcing. Additionally, the coupled model exhibits a deeper and more realistic simulation of the ocean mixed-layer depth with a more pronounced seasonal cycle, driven by the enhanced wind-driven mixing. On the other hand, our ROMSOC simulations reveal a negative cloud cover bias and related biases in surface radiative fluxes off the coast of southern California, a common issue in climate models. 
651 4 |a United States--US 
651 4 |a California 
653 |a Ocean models 
653 |a Bias 
653 |a Sea surface temperature 
653 |a Biogeochemistry 
653 |a Surface temperature 
653 |a Upwelling 
653 |a Supercomputers 
653 |a Cloud cover 
653 |a Atmosphere 
653 |a Ocean mixed layer 
653 |a Wind stress 
653 |a Ocean currents 
653 |a Radiation 
653 |a Climate change 
653 |a General circulation models 
653 |a Coasts 
653 |a Configurations 
653 |a Regional development 
653 |a Radiative forcing 
653 |a Mixed layer depth 
653 |a Simulation 
653 |a Graphics processing units 
653 |a Mesoscale phenomena 
653 |a Regional climates 
653 |a Heat flux 
653 |a Mesoscale processes 
653 |a Clouds 
653 |a Central processing units--CPUs 
653 |a Seasonal variation 
653 |a Models 
653 |a Wind 
653 |a Productivity 
653 |a Regional climate models 
653 |a Small-scale models 
653 |a Oceans 
653 |a California Current 
653 |a Coupling 
653 |a Coastal upwelling 
653 |a Modelling 
653 |a Global climate 
653 |a Heat transfer 
653 |a Graphics 
653 |a Climate models 
653 |a Ocean circulation 
653 |a Hybrid systems 
653 |a Climate 
653 |a Mechanical properties 
653 |a Environmental 
700 1 |a Leclair, Matthieu  |u Center for Climate Systems Modeling (C2SM), Zurich, ETH Zurich, Switzerland 
700 1 |a Muennich, Matthias  |u Environmental Physics, Institute of Biogeochemistry and Pollutant Dynamics, Zurich, ETH Zurich, Switzerland 
700 1 |a Gruber, Nicolas  |u Environmental Physics, Institute of Biogeochemistry and Pollutant Dynamics, Zurich, ETH Zurich, Switzerland; Center for Climate Systems Modeling (C2SM), Zurich, ETH Zurich, Switzerland 
773 0 |t Geoscientific Model Development  |g vol. 18, no. 18 (2025), p. 6255-6275 
786 0 |d ProQuest  |t Engineering Database 
856 4 1 |3 Citation/Abstract  |u https://www.proquest.com/docview/3253520121/abstract/embedded/BP4M5IEWWR03UZF2?source=fedsrch 
856 4 0 |3 Full Text  |u https://www.proquest.com/docview/3253520121/fulltext/embedded/BP4M5IEWWR03UZF2?source=fedsrch 
856 4 0 |3 Full Text - PDF  |u https://www.proquest.com/docview/3253520121/fulltextPDF/embedded/BP4M5IEWWR03UZF2?source=fedsrch