Journal of Advances in Modeling Earth Systems最新文献

{"title":"Flower-Type Organized Trade-Wind Cumulus: A Multi-Day Lagrangian Large Eddy Simulation Intercomparison Study","authors":"Girish Nigamanth Raghunathan,&nbsp;Peter Blossey,&nbsp;Steven Boeing,&nbsp;Leif Denby,&nbsp;Salima Ghazayel,&nbsp;Thijs Heus,&nbsp;Jan Kazil,&nbsp;Roel Neggers","doi":"10.1029/2024MS004864","DOIUrl":"https://doi.org/10.1029/2024MS004864","url":null,"abstract":"<p>Shallow cumulus cloud fields in subtropical marine trade wind environments, particularly over the tropical Atlantic Ocean, show distinct organizational patterns. Among these, Flower-type clouds are characterized by expansive stratiform cloud patches surrounded by regions of scattered convection. The objectives of this study were (a) to construct a case study of a time period during the <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msup>\u0000 <mtext>EUREC</mtext>\u0000 <mn>4</mn>\u0000 </msup>\u0000 </mrow>\u0000 <annotation> ${text{EUREC}}^{4}$</annotation>\u0000 </semantics></math>A/ATOMIC field campaign when Flower-type organization was observed, (b) to evaluate the fidelity of a multi-model ensemble of large eddy simulations of that case, and (c) to analyze the interaction between cloud and precipitation processes and mesoscale organization in the simulations. The simulations follow a quasi-Lagrangian trajectory, allowing mesoscale features to develop over time in a domain that follows the boundary-layer airmass. The results show a broad agreement in simulated thermodynamic properties across different LES codes, with Flower-type cloud patches appearing within hours of each other. The consensus among models is consistent with observations made during the <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msup>\u0000 <mtext>EUREC</mtext>\u0000 <mn>4</mn>\u0000 </msup>\u0000 </mrow>\u0000 <annotation> ${text{EUREC}}^{4}$</annotation>\u0000 </semantics></math>A/ATOMIC field campaign on the specific day of interest. The cloud structure reveals three distinct peaks in the joint probability densities of cloud base and cloud top height, with the dominant peak at any given time influenced by the stage of cloud organization. The simulated cloud system evolution reveals consistent occurrence of maxima in liquid water path and rain rate before Flower reaches its maximum length scale. Targeted sensitivity tests reveal a weak relationship between Cloud Droplet Number concentration and the extent/degree/type of organization.</p>","PeriodicalId":14881,"journal":{"name":"Journal of Advances in Modeling Earth Systems","volume":"17 10","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2024MS004864","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145223816","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evaluating Turbulence Parameterizations at Gray Zone Resolutions for the Ocean Surface Boundary Layer","authors":"Zihan Chen,&nbsp;Jacob Wenegrat,&nbsp;Tomás Chor,&nbsp;Patrick Marchesiello","doi":"10.1029/2025MS005104","DOIUrl":"https://doi.org/10.1029/2025MS005104","url":null,"abstract":"&lt;p&gt;Turbulent mixing in ocean boundary layers is often fully parameterized as a subgrid-scale process in realistic ocean simulations. However, recent submesoscale modeling studies have advanced to a horizontal grid spacing of &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;O&lt;/mi&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; $mathcal{O}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;(10 m) that is comparable to, or even smaller than, the typical depth of the turbulent surface boundary layer. Meanwhile, efforts toward realistic large-eddy simulations (LES) nested within regional models require subdomains with similar grid spacings, where turbulent eddies are partially resolved in the mixed layer. The range of intermediate grid spacings, often known as the “gray zone,” presents challenges for model configuration and analysis, including uncertainties regarding the behavior of common turbulence closures outside of their ideal use cases. In this study, we evaluate three common configurations for subgrid turbulence—&lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;k&lt;/mi&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; $k$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;-&lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;ϵ&lt;/mi&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${epsilon}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;, Smagorinsky, and an implicit no-closure method—in the gray zone resolutions for the ocean surface mixed layer. Results indicate that, in the gray zone with partially resolved boundary layer turbulence, &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;k&lt;/mi&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; $k$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;-&lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;ϵ&lt;/mi&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; ${epsilon}$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt; can produce accurate mixed layer profiles with little sensitivity to grid spacing. However, it overly damps turbulent motions, significantly reducing small-scale variability that could otherwise be captured. The Smagorinsky closure and the implicit method, in contrast, exhibit higher sensitivity to grid spacing, initially performing poorly but converging toward baseline solutions at finer grids. Our findings provide guidance for submesoscale and turbulent-scale modeling, recommending Smagorinsky or implicit methods for nested domains which prioritize resolved turbulence, such as LES. The &lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;semantics&gt;\u0000 &lt;mrow&gt;\u0000 &lt;mi&gt;k&lt;/mi&gt;\u0000 &lt;/mrow&gt;\u0000 &lt;annotation&gt; $k$&lt;/annotation&gt;\u0000 &lt;/semantics&gt;&lt;/math&gt;-&lt;span&gt;&lt;/span&gt;&lt;math&gt;\u0000 &lt;","PeriodicalId":14881,"journal":{"name":"Journal of Advances in Modeling Earth Systems","volume":"17 10","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2025MS005104","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145223842","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Response of African Easterly Waves to a Warming Climate: A Convection-Permitting Approach","authors":"K. M. Núñez Ocasio,&nbsp;E. M. Dougherty,&nbsp;Z. L. Moon,&nbsp;C. A. Davis","doi":"10.1029/2025MS005146","DOIUrl":"https://doi.org/10.1029/2025MS005146","url":null,"abstract":"<p>As the atmosphere warms, tropical cyclones (TCs) and their precursors, like African easterly waves (AEWs), will respond. While TC changes in a warmer climate have been studied, AEW evolution remains uncertain. Using a novel storm-resolving regional Model for Prediction Across Scales setup, we examine the response of AEWs during an active historic period. Our findings indicate that AEWs over Africa will become significantly more intense, wetter, and with greater water vapor content. Future AEWs in this scenario and period will also experience a larger saturation deficit over the continent, indicating significant changes in both temperature and moisture influencing growth. The location of AEWs does not change under the future climate scenario, but TC genesis and overall AEW propagation for a case study is slower. Slower progression of AEWs can have dangerous ramifications, including prolonged periods of heavy rainfall, increasing the risk of flooding over Africa. These results highlight the need for high-resolution modeling to better understand AEW behavior in a warming climate and their potential impacts on extreme weather.</p>","PeriodicalId":14881,"journal":{"name":"Journal of Advances in Modeling Earth Systems","volume":"17 10","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2025MS005146","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145197264","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Minimal, Adiabatic Example of Sudden Stratospheric Warming","authors":"Joseph Mouallem,&nbsp;Weiye Yao,&nbsp;Lucas Harris,&nbsp;Shian-Jiann Lin,&nbsp;Xi Chen","doi":"10.1029/2024MS004760","DOIUrl":"https://doi.org/10.1029/2024MS004760","url":null,"abstract":"<p>Sudden Stratospheric Warming (SSW) are extreme weather events that can significantly impact weather patterns on short to subseasonal to seasonal timescales. In this study, we present a new idealized test case of a Sudden Stratospheric Warming (SSW) event implemented in GFDL's FV3 dynamical core. The initial condition features a wintertime stratospheric circulation with a westerly jet in the Northern Hemisphere and an easterly jet in the Southern Hemisphere. In the absence of tropospheric wave forcing, the model preserves the stratospheric circulation for approximately 200 days. To induce SSW, we introduce a moving mountain to generate planetary waves. Wavenumber-1 forcing led to a vortex displacement SSW, while wavenumber-2 forcing produced a vortex split SSW, consistent with observational data and literature. This minimal setup offers a controlled environment for studying SSW dynamics and serves as a useful testbed for evaluating the ability of dynamical cores to capture key stratospheric processes and troposphere-stratosphere interactions.</p>","PeriodicalId":14881,"journal":{"name":"Journal of Advances in Modeling Earth Systems","volume":"17 9","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2024MS004760","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145146776","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Exploring Advectable Latent Representations for Droplet Size Distributions With Physics-Informed Autoencoders","authors":"Kang-En Huang,&nbsp;Minghuai Wang,&nbsp;Daniel Rosenfeld,&nbsp;Yannian Zhu","doi":"10.1029/2024MS004821","DOIUrl":"https://doi.org/10.1029/2024MS004821","url":null,"abstract":"<p>Investigating the role of clouds and precipitation in the Earth system necessitates microphysical schemes capable of accurately describing the evolution of hydrometeor particle size distribution (PSD), while maintaining low computational costs implementable in atmospheric models. Machine learning (ML) offers a promising approach to replace computationally expensive bin microphysical schemes with efficient emulations. However, many existing ML emulations predict moments of PSDs as prognostic variables, inheriting structural limitations from traditional bulk schemes. In contrast, latent variables directly discovered by ML have the potential to represent PSDs more accurately. However, their inherent nonlinearity breaks the conservation property under advection and diffusion, limiting their applicability in online simulations. To address this dilemma, we propose Non-negative weighted integrals (NWIs), formulated as weighted integrals of PSD with learnable non-negative weight functions. NWI provides the most general mathematical form for advectable microphysical prognostic variables. We conducted unsupervised learning over a liquid droplet PSD data set generated from ensemble large eddy simulations with Spectral Bin Microphysics (SBM). We used autoencoders that are physics-informed by NWI’s formulation to learn the optimal PSD representations from the data, and compared NWIs with traditional moment approaches in bulk schemes on their ability to represent PSDs in actual bin scheme simulations. Results show that NWIs can capture the critical information of medium-sized droplets, and outperform traditional cloud-rain moment approaches in terms of PSD reconstruction error, indicating improved PSD information compression efficiency. With these properties, NWIs are advantageous over moments as fully prognostic variables to build accurate ML-based bin-emulating schemes.</p>","PeriodicalId":14881,"journal":{"name":"Journal of Advances in Modeling Earth Systems","volume":"17 9","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2024MS004821","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145146511","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Development and Validation of Soil Frost Heave Scheme in the Community Land Model 5.0","authors":"Pengfei Xu,&nbsp;Xianhong Meng,&nbsp;Shihua Lyu,&nbsp;Zhaoguo Li,&nbsp;Yan Chang,&nbsp;Shaoying Wang,&nbsp;Lin Zhao,&nbsp;Yue Xu,&nbsp;Danrui Sheng,&nbsp;Wei Jin,&nbsp;Xinyi Gu,&nbsp;Zhenghao Li","doi":"10.1029/2025MS005089","DOIUrl":"10.1029/2025MS005089","url":null,"abstract":"<p>Soil frost heave from freezing–thawing (FT) affects soil structure, hydrothermal properties, and land-atmosphere interactions, affecting the reliability of permafrost engineering and increasing uncertainty in model simulations. However, most Land Surface Models (LSMs), including Community Land Model 5.0 (CLM5.0), do not simulate frost heave. To address this, a frost heave parameterization scheme, based on the porosity rate function, was developed and integrated into CLM5.0. The enhanced model (with proposed frost heave scheme) was validated at site and regional scales, focusing on its effects on soil structure, hydrothermal properties, and transfer processes on the Tibetan Plateau (TP). Results show the enhanced model accurately simulates changes in soil thickness and porosity during FT cycles, improving hydrothermal properties' simulations during thawing and representing bidirectional thawing within soil layers. At the regional scale, seasonal soil deformation along the Qinghai-Tibet Highway simulated by the enhanced model closely aligns with field experiments and InSAR data. The enhanced model predicts higher soil temperatures in southeastern TP and lower ones in the northwest compared to the original model. Additionally, the enhanced model simulates increased soil moisture especially in the Three Rivers Source region compared to the original model, which aligning better with observations. Integrating the proposed scheme in CLM5.0 advances the representation of FT processes and provides a foundation for refining land surface, regional, and global modeling frameworks.</p>","PeriodicalId":14881,"journal":{"name":"Journal of Advances in Modeling Earth Systems","volume":"17 9","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2025MS005089","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145129376","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Revisiting Machine Learning Approaches for Short- and Longwave Radiation Inference in Weather and Climate Models","authors":"Guillaume Bertoli,&nbsp;Salman Mohebi,&nbsp;Firat Ozdemir,&nbsp;Jonas Jucker,&nbsp;Stefan Rüdisühli,&nbsp;Fernando Perez-Cruz,&nbsp;Mathieu Salzmann,&nbsp;Sebastian Schemm","doi":"10.1029/2025MS004956","DOIUrl":"10.1029/2025MS004956","url":null,"abstract":"<p>This paper explores Machine Learning (ML) parameterizations for radiative transfer in the ICOsahedral Nonhydrostatic weather and climate model (ICON) and investigates the achieved ML model speed-up with ICON running on graphics processing units (GPUs). Five ML models, with varying complexity and size, are coupled to ICON; more specifically, a multilayer perceptron (MLP), a Unet model, a bidirectional recurrent neural network with long short-term memory (BiLSTM), a vision transformer (ViT), and a random forest (RF) as a baseline. The ML parameterizations are coupled to the ICON code that includes OpenACC compiler directives to enable GPU support. The coupling is done with the PyTorch-Fortran coupler developed at NVIDIA. The most accurate model is the BiLSTM with a physics-informed normalization strategy, a penalty for the heating rates during training, a Gaussian smoothing as postprocessing and a simplified computation of the fluxes at the upper levels to ensure stability of the ICON model top. The presented setup enables stable aquaplanet simulations with ICON for several weeks at a resolution of about 80 km and compares well with the physics-based default radiative transfer parameterization, ecRad. Our results indicate that the compute requirements of the ML models that can ensure the stability of ICON are comparable to GPU optimized classical physics parameterizations in terms of memory consumption and computational speed.</p>","PeriodicalId":14881,"journal":{"name":"Journal of Advances in Modeling Earth Systems","volume":"17 9","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2025MS004956","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145129276","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Advancing Hurricane Forecasting With AI Models for Track and Intensity Prediction","authors":"Kumar Ankur,&nbsp;Sujit Roy,&nbsp;Christopher E. Phillips,&nbsp;Udaysankar Nair,&nbsp;Manil Maskey,&nbsp;Rahul Ramachandran","doi":"10.1029/2024MS004822","DOIUrl":"10.1029/2024MS004822","url":null,"abstract":"<p>Hurricane forecasting has traditionally relied on numerical weather prediction (NWP) models. However, advancements in artificial intelligence (AI) offer new opportunities to improve forecasting accuracy. This study presents a novel evaluation of the FourCastNet model, trained on MERRA-2 and ERA5 data sets. We perform a comprehensive comparison between the FourCastNet model forecasts and those simulated by the Weather Research and Forecating (WRF) model, a NWP model, assessing both the accuracy and radial distribution of hurricane structure. This comparison provides their representation of hurricane dynamics, including differences in track prediction and intensity forecasts. Additionally, the study addresses the challenge of bias in hurricane intensity forecasts. To overcome this, this study presents a comprehensive assessment of three hurricane intensity estimation models, HxUnet, HxCNN, and HxGNN. Our results demonstrate that HxUnet consistently outperforms the other models, achieving up to a 79% reduction in maximum sustained wind speed errors and a 59% reduction in Mean Sea Level Pressure errors. This significant improvement underscores the potential of AI models to enhance the precision of hurricane intensity forecasts. This research advances the application of AI in meteorology and establishes a foundation for future studies aimed at improving hurricane prediction and mitigation efforts.</p>","PeriodicalId":14881,"journal":{"name":"Journal of Advances in Modeling Earth Systems","volume":"17 9","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2024MS004822","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145110904","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Tracer Budgets on Lagrangian Trajectories","authors":"Wenrui Jiang,&nbsp;Thomas W. N. Haine","doi":"10.1029/2024MS004848","DOIUrl":"10.1029/2024MS004848","url":null,"abstract":"<p>The Lagrangian particle method is widely used to understand scalar tracer concentration fields in models of the atmosphere and oceans. Simulating virtual particles provides an alternative description of advection to the Eulerian representation in models and aids in identifying pathways, timescales, and connectivity. Atmospheric and oceanic models solve advection-diffusion-reaction equations to simulate tracers, in which only the advective component is captured by traditional Lagrangian approaches. In this work, we report a novel method that closes tracer budgets on Lagrangian trajectories in a manner consistent with Eulerian budgets in finite-volume models. The scalar tracer concentrations on grid cell walls are derived from the model advection scheme and then interpolated inside grid boxes along streamlines. The divergence of the diffusive flux and reaction terms are interpolated based on velocity and tracer concentration, ensuring the tracer budget closes in terms of both trajectory and volume integrals. Compared to the Eulerian budget analysis, which considers a fixed volume, our method quantifies the tracer evolution within a volume that moves along with the flow. We demonstrate the method using a case study of Southern Ocean biogeochemistry. Another case study involves analyzing the heat budget of the 2011 Western Australian marine heat wave. The method bridges the gap between Eulerian budget and Lagrangian particle analyses by representing the advective processes with particle movements and interpolating the diffusive and reactive processes onto trajectories in a way consistent with the finite-volume description.</p>","PeriodicalId":14881,"journal":{"name":"Journal of Advances in Modeling Earth Systems","volume":"17 9","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2024MS004848","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145111056","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Examining the Fidelity of Leith Subgrid Closures for Parameterizing Mesoscale Eddies in Idealized and Global (NEMO) Ocean Models","authors":"T. Wilder,&nbsp;T. Kuhlbrodt","doi":"10.1029/2025MS004950","DOIUrl":"10.1029/2025MS004950","url":null,"abstract":"<p>Eddy-permitting models struggle to simulate accurate Southern Ocean (SO) circulation. In particular, the medium resolution Hadley Center Global Coupled model in CMIP6 exhibits a warm SO bias and weak Antarctic Circumpolar Current (ACC) transport. These issues are attributed to a poor representation of mesoscale eddies, which also impair the simulated transport of heat and carbon. To rectify these problems, two momentum closures (harmonic and biharmonic) are implemented in the Nucleus for European Modeling of the Ocean general circulation model: 2D Leith and Quasi-Geostrophic Leith. These Leith closures aim to capture the correct cascades of energy and enstrophy in quasi two-dimensional models. Additionally, the harmonic Leith viscosity coefficients can replace the traditional Gent-McWilliams and Redi diffusivity coefficients. In this work we explore Leith closures in an eddy-resolving channel model and an eddy-permitting forced global ocean sea-ice model, Global Ocean Sea-Ice 9 (GOSI9). The idealized model shows the Leith implementation functions as intended. In the GOSI9 configuration, the harmonic Leith schemes increase the ACC transport by <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mn>10</mn>\u0000 <mo>−</mo>\u0000 <mn>17</mn>\u0000 </mrow>\u0000 <annotation> $10-17$</annotation>\u0000 </semantics></math>%. This is in response to isopycnal flattening across Drake Passage that reduces a strong Westward flow at <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <mn>60</mn>\u0000 <mo>°</mo>\u0000 </mrow>\u0000 <annotation> $60{}^{circ}$</annotation>\u0000 </semantics></math>S. This increase in ACC transport coincides with reduced warming around Antarctica and reduction of cold biases in the Atlantic. Both viscosity schemes also lead to a warm model drift. Swapping biharmonic with quasi-geostrophic Leith viscosity in GOSI9 results in one of the strongest ACC transports, along with improvements to some biases in the Atlantic.</p>","PeriodicalId":14881,"journal":{"name":"Journal of Advances in Modeling Earth Systems","volume":"17 9","pages":""},"PeriodicalIF":4.6,"publicationDate":"2025-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2025MS004950","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145101485","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}