Stable Machine‐Learning Parameterization of Subgrid Processes in a Comprehensive Atmospheric Model Learned From Embedded Convection‐Permitting Simulations

Abstract Modern climate projections often suffer from inadequate spatial and temporal resolution due to computational limitations, resulting in inaccurate representations of sub‐grid processes. A promising technique to address this is the multiscale modeling framework (MMF), which embeds a kilometer...

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Main Authors: Zeyuan Hu, Akshay Subramaniam, Zhiming Kuang, Jerry Lin, Sungduk Yu, Walter M. Hannah, Noah D. Brenowitz, Josh Romero, Michael S. Pritchard
Format: Article
Language:English
Published: American Geophysical Union (AGU) 2025-07-01
Series:Journal of Advances in Modeling Earth Systems
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Online Access:https://doi.org/10.1029/2024MS004618
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author Zeyuan Hu
Akshay Subramaniam
Zhiming Kuang
Jerry Lin
Sungduk Yu
Walter M. Hannah
Noah D. Brenowitz
Josh Romero
Michael S. Pritchard
author_facet Zeyuan Hu
Akshay Subramaniam
Zhiming Kuang
Jerry Lin
Sungduk Yu
Walter M. Hannah
Noah D. Brenowitz
Josh Romero
Michael S. Pritchard
author_sort Zeyuan Hu
collection DOAJ
description Abstract Modern climate projections often suffer from inadequate spatial and temporal resolution due to computational limitations, resulting in inaccurate representations of sub‐grid processes. A promising technique to address this is the multiscale modeling framework (MMF), which embeds a kilometer‐resolution cloud‐resolving model (CRM) within each atmospheric column of a host climate model to replace traditional convection and cloud parameterizations. Machine learning offers a unique opportunity to make MMF more accessible by emulating the embedded CRM and reducing its substantial computational cost. Although many studies have demonstrated proof‐of‐concept success of achieving stable hybrid simulations, it remains a challenge to achieve near operational‐level success with real geography and comprehensive variable emulation that includes, for example, explicit cloud condensate coupling. In this study, we present a stable hybrid model capable of integrating for at least 5 years with near operational‐level complexity, including coarse‐grid geography, seasonality, explicit cloud condensate and wind predictions, and land coupling. Our model demonstrates skillful online performance, achieving a 5‐year zonal mean tropospheric temperature bias within 2 K, water vapor bias within 1 g/kg, and a precipitation root mean square error of 0.96 mm/day. Key factors contributing to our online performance include an expressive U‐Net architecture and physical thermodynamic constraints for microphysics. With microphysical constraints mitigating unrealistic cloud formation, our work is the first to demonstrate realistic multi‐year cloud condensate climatology under the MMF framework. Despite these advances, online diagnostics reveal persistent biases in certain regions, highlighting the need for innovative strategies to further optimize online performance.
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spelling doaj-art-09345e1b93a943c2bcad4143b55b4ce02025-07-28T14:46:59ZengAmerican Geophysical Union (AGU)Journal of Advances in Modeling Earth Systems1942-24662025-07-01177n/an/a10.1029/2024MS004618Stable Machine‐Learning Parameterization of Subgrid Processes in a Comprehensive Atmospheric Model Learned From Embedded Convection‐Permitting SimulationsZeyuan Hu0Akshay Subramaniam1Zhiming Kuang2Jerry Lin3Sungduk Yu4Walter M. Hannah5Noah D. Brenowitz6Josh Romero7Michael S. Pritchard8NVIDIA Research Santa Clara CA USANVIDIA Research Santa Clara CA USAHarvard University Cambridge MA USAUniversity of California at Irvine Irvine CA USAMultimodal Cognitive AI Intel Labs Santa Clara CA USALawrence Livermore National Laboratory Livermore CA USANVIDIA Research Santa Clara CA USANVIDIA Research Santa Clara CA USANVIDIA Research Santa Clara CA USAAbstract Modern climate projections often suffer from inadequate spatial and temporal resolution due to computational limitations, resulting in inaccurate representations of sub‐grid processes. A promising technique to address this is the multiscale modeling framework (MMF), which embeds a kilometer‐resolution cloud‐resolving model (CRM) within each atmospheric column of a host climate model to replace traditional convection and cloud parameterizations. Machine learning offers a unique opportunity to make MMF more accessible by emulating the embedded CRM and reducing its substantial computational cost. Although many studies have demonstrated proof‐of‐concept success of achieving stable hybrid simulations, it remains a challenge to achieve near operational‐level success with real geography and comprehensive variable emulation that includes, for example, explicit cloud condensate coupling. In this study, we present a stable hybrid model capable of integrating for at least 5 years with near operational‐level complexity, including coarse‐grid geography, seasonality, explicit cloud condensate and wind predictions, and land coupling. Our model demonstrates skillful online performance, achieving a 5‐year zonal mean tropospheric temperature bias within 2 K, water vapor bias within 1 g/kg, and a precipitation root mean square error of 0.96 mm/day. Key factors contributing to our online performance include an expressive U‐Net architecture and physical thermodynamic constraints for microphysics. With microphysical constraints mitigating unrealistic cloud formation, our work is the first to demonstrate realistic multi‐year cloud condensate climatology under the MMF framework. Despite these advances, online diagnostics reveal persistent biases in certain regions, highlighting the need for innovative strategies to further optimize online performance.https://doi.org/10.1029/2024MS004618parameterizationmachine learningconvectionclimatehybrid simulation
spellingShingle Zeyuan Hu
Akshay Subramaniam
Zhiming Kuang
Jerry Lin
Sungduk Yu
Walter M. Hannah
Noah D. Brenowitz
Josh Romero
Michael S. Pritchard
Stable Machine‐Learning Parameterization of Subgrid Processes in a Comprehensive Atmospheric Model Learned From Embedded Convection‐Permitting Simulations
Journal of Advances in Modeling Earth Systems
parameterization
machine learning
convection
climate
hybrid simulation
title Stable Machine‐Learning Parameterization of Subgrid Processes in a Comprehensive Atmospheric Model Learned From Embedded Convection‐Permitting Simulations
title_full Stable Machine‐Learning Parameterization of Subgrid Processes in a Comprehensive Atmospheric Model Learned From Embedded Convection‐Permitting Simulations
title_fullStr Stable Machine‐Learning Parameterization of Subgrid Processes in a Comprehensive Atmospheric Model Learned From Embedded Convection‐Permitting Simulations
title_full_unstemmed Stable Machine‐Learning Parameterization of Subgrid Processes in a Comprehensive Atmospheric Model Learned From Embedded Convection‐Permitting Simulations
title_short Stable Machine‐Learning Parameterization of Subgrid Processes in a Comprehensive Atmospheric Model Learned From Embedded Convection‐Permitting Simulations
title_sort stable machine learning parameterization of subgrid processes in a comprehensive atmospheric model learned from embedded convection permitting simulations
topic parameterization
machine learning
convection
climate
hybrid simulation
url https://doi.org/10.1029/2024MS004618
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