{"title":"Neural Data Assimilation for Regime Shift Monitoring of an Idealized AMOC Chaotic Model","authors":"Perrine Bauchot, Angélique Drémeau, Florian Sévellec, Ronan Fablet","doi":"10.1029/2024MS004462","DOIUrl":"https://doi.org/10.1029/2024MS004462","url":null,"abstract":"<p>Data assimilation (DA) reconstructs and forecasts the dynamics of geophysical processes using available observations and physical a priori. Recently, the hybridization of DA and deep learning has opened new perspectives to address model-data interactions. This paper explores its potential contribution to the analysis of a chaotic oceanic phenomenon: the centennial to millennial variability of the North Atlantic ocean circulation during the last glacial period. The implemented neural approach—4DVarNet—yields meaningful improvements over a classical variational DA method in reconstructing regime shifts of the Atlantic Meridional Overturning Circulation (AMOC), especially when fewer observations are available. Interestingly, results exhibit that exploiting explicitly the a priori dynamical model does not lead to better performances compared to a data-driven model. Additionally, we compare four sampling strategies to assess how observation patterns influence the capture of unstable AMOC phases. We highlight the gain of regular over random sampling strategies, with reconstruction errors dropping below 2% for a 100-year sampling period. We find that monitoring the AMOC with regular clusters of three consecutive observation points can reduce errors by a factor of five. Eventually, we assess 4DVarNet's robustness in reconstructing a partially-observed system and in generalizing to different dynamical regimes. We also investigate on the maximum sampling periods that 4DVarNet can assimilate without compromising reconstruction quality. This study, based on an idealized yet complex physical model, suggests that neural approaches trained on observations wisely acquired could improve the monitoring of regime shifts in the context of climate change.</p>","PeriodicalId":14881,"journal":{"name":"Journal of Advances in Modeling Earth Systems","volume":"17 4","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024MS004462","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143853018","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}
Andrea Polesello, Giousef Alexandros Charinti, Agostino Niyonkuru Meroni, Caroline Jane Muller, Claudia Pasquero
{"title":"Intensity Oscillations of Tropical Cyclones: Surface Versus Mid and Upper Tropospheric Processes","authors":"Andrea Polesello, Giousef Alexandros Charinti, Agostino Niyonkuru Meroni, Caroline Jane Muller, Claudia Pasquero","doi":"10.1029/2024MS004613","DOIUrl":"https://doi.org/10.1029/2024MS004613","url":null,"abstract":"<p>Some of the classical models of tropical cyclone intensification predict tropical cyclones to intensify up to a steady intensity, which depends on surface fluxes only, without any relevant role played by convective motions in the troposphere, typically assumed to have a moist adiabatic lapse rate. Simulations performed using the non-hydrostatic, high-resolution model System for Atmosphere Modeling in idealized settings (rotating radiative-convective equilibrium on a doubly periodic domain) show early intensification consistent with these theoretical expectations, but different intensity evolution, with the cyclone undergoing an oscillation in wind speed. This oscillation can be linked to feedbacks between the cyclone intensity and air buoyancy: convective heating, radiative heating, and mixing with warm low stratospheric air warm the mid and upper troposphere of the cyclone stabilizing the air column and thus reducing its intensity. After the intensity decay phase, mid and upper tropospheric cooling, mostly through cold advection from the surroundings, cooled by radiation, rebuilds Convective Available Potential Energy, that peaks just before a new intensification phase. These idealized simulations thus highlight the potentially important interactions between a tropical cyclone, its environment and radiation.</p>","PeriodicalId":14881,"journal":{"name":"Journal of Advances in Modeling Earth Systems","volume":"17 4","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024MS004613","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143852658","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}
Gregory LeClaire Wagner, Adeline Hillier, Navid C. Constantinou, Simone Silvestri, Andre Souza, Keaton J. Burns, Chris Hill, Jean-Michel Campin, John Marshall, Raffaele Ferrari
{"title":"Formulation and Calibration of CATKE, a One-Equation Parameterization for Microscale Ocean Mixing","authors":"Gregory LeClaire Wagner, Adeline Hillier, Navid C. Constantinou, Simone Silvestri, Andre Souza, Keaton J. Burns, Chris Hill, Jean-Michel Campin, John Marshall, Raffaele Ferrari","doi":"10.1029/2024MS004522","DOIUrl":"https://doi.org/10.1029/2024MS004522","url":null,"abstract":"<p>We describe CATKE, a parameterization for fluxes associated with small-scale or “microscale” ocean turbulent mixing on scales between 1 and 100 m. CATKE uses a downgradient formulation that depends on a prognostic turbulent kinetic energy (TKE) variable and a diagnostic mixing length scale that includes a dynamic convective adjustment (CA) component. With its dynamic convective mixing length, CATKE predicts not just the depth spanned by convective plumes but also the characteristic convective mixing timescale, an important aspect of turbulent convection not captured by simpler static CA schemes. As a result, CATKE can describe the competition between convection and other processes such as shear-driven mixing and baroclinic restratification. To calibrate CATKE, we use Ensemble Kalman Inversion to minimize the error between 21 large eddy simulations (LESs) and predictions of the LES data by CATKE-parameterized single column simulations at three different vertical resolutions. We find that CATKE makes accurate predictions of both idealized and realistic LES compared to microscale turbulence parameterizations commonly used in climate models.</p>","PeriodicalId":14881,"journal":{"name":"Journal of Advances in Modeling Earth Systems","volume":"17 4","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024MS004522","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143853015","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}
Takaya Uchida, 内田貴也, Quentin Jamet, Andrew C. Poje, Nicolas Wienders, Luolin Sun, 孙洛琳, William K. Dewar
{"title":"Dynamics and Thermodynamics of the Boussinesq North Atlantic Eddy Kinetic Energy Spectral Budget","authors":"Takaya Uchida, 内田貴也, Quentin Jamet, Andrew C. Poje, Nicolas Wienders, Luolin Sun, 孙洛琳, William K. Dewar","doi":"10.1029/2024MS004781","DOIUrl":"https://doi.org/10.1029/2024MS004781","url":null,"abstract":"<p>Statistical characterization of oceanic flows has been a long standing issue; such information is invaluable for formulating hypotheses and testing them. It also allows us to understand the energy pathways within the ocean, which is highly turbulent. Here, we apply the wavelet approach to wavenumber spectral analysis, which has recently been proved to be beneficial in quantifying the spatially heterogeneous and anisotropic nature of oceanic flows. Utilizing an eddy-rich ensemble simulation of the North Atlantic, we are able to examine the spectral transfers of eddy kinetic energy (EKE) and effect of potential energy, here defined via dynamic enthalpy, on the EKE spectral budget. We find that vertical advection of EKE modulates the up- and down-scale direction and strength of EKE spectral flux throughout the North Atlantic domain. The vertical eddy buoyancy flux tends to be small below the mixed layer, suggesting that the flow is largely adiabatic. In maintaining this adiabatic nature, the eddy advection of dynamic enthalpy and practical salinity tend to partially compensate for the eddy advection of potential temperature; this partial cancellation between temperature and salinity is similar to the thermodynamic spice variable.</p>","PeriodicalId":14881,"journal":{"name":"Journal of Advances in Modeling Earth Systems","volume":"17 4","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024MS004781","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143852656","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}
Simone Silvestri, Gregory L. Wagner, Navid C. Constantinou, Christopher N. Hill, Jean-Michel Campin, Andre N. Souza, Siddhartha Bishnu, Valentin Churavy, John Marshall, Raffaele Ferrari
{"title":"A GPU-Based Ocean Dynamical Core for Routine Mesoscale-Resolving Climate Simulations","authors":"Simone Silvestri, Gregory L. Wagner, Navid C. Constantinou, Christopher N. Hill, Jean-Michel Campin, Andre N. Souza, Siddhartha Bishnu, Valentin Churavy, John Marshall, Raffaele Ferrari","doi":"10.1029/2024MS004465","DOIUrl":"https://doi.org/10.1029/2024MS004465","url":null,"abstract":"<p>We describe an ocean hydrostatic dynamical core implemented in Oceananigans optimized for Graphical Processing Unit (GPU) architectures. On 64 A100 GPUs, equivalent to 16 computational nodes in current state-of-the-art supercomputers, our dynamical core can simulate a decade of near-global ocean dynamics per wall-clock day at an 8-km horizontal resolution; a resolution adequate to resolve the ocean's mesoscale eddy field. Such efficiency, achieved with relatively modest hardware resources, suggests that climate simulations on GPUs can incorporate fully eddy-resolving ocean models. This removes a major source of systematic bias in current IPCC coupled model projections, the parameterization of ocean eddies, and represents a major advance in climate modeling. We discuss the computational strategies, focusing on GPU-specific optimization and numerical implementation details that enable such high performance.</p>","PeriodicalId":14881,"journal":{"name":"Journal of Advances in Modeling Earth Systems","volume":"17 4","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024MS004465","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143852951","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}
Florian Le Guillou, Bertrand Chapron, Marie-Helene Rio
{"title":"VarDyn: Dynamical Joint-Reconstructions of Sea Surface Height and Temperature From Multi-Sensor Satellite Observations","authors":"Florian Le Guillou, Bertrand Chapron, Marie-Helene Rio","doi":"10.1029/2024MS004689","DOIUrl":"https://doi.org/10.1029/2024MS004689","url":null,"abstract":"<p>The VarDyn hybrid methodology, which combines minimal physically based constraints with a variational scheme, is demonstrated to enhance the mapping of sea surface height (SSH) and sea surface temperature (SST). By synthesizing multi-modal satellite observations, VarDyn produces SSH and SST maps with improved accuracy compared to operational products, achieving reductions in Root Mean Square Error and enhancements in effective spatial resolution. While most improvements are observed in highly energetic ocean regions, SSH map accuracy also improves slightly in low-energy regions—a significant advancement over other methods. VarDyn SSH fields and the associated geostrophic velocities show strong agreement with newly available high-resolution instantaneous SWOT estimates. Notably, the assimilation of SST proves particularly beneficial for SSH reconstruction when only two altimeters are available. The VarDyn methodology potentially offers a robust framework for refining climate SSH records by jointly assimilating SSH data from two altimeters and SST data from microwave sensors.</p>","PeriodicalId":14881,"journal":{"name":"Journal of Advances in Modeling Earth Systems","volume":"17 4","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024MS004689","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143856696","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 Robust Constraint on the Response of Convective Mass Fluxes to Warming","authors":"Andrew I. L. Williams, Nadir Jeevanjee","doi":"10.1029/2024MS004695","DOIUrl":"https://doi.org/10.1029/2024MS004695","url":null,"abstract":"<p>A fundamental quantity in tropical dynamics is the “convective mass flux,” which measures the rate at which mass is transported upwards per unit area in convective updrafts. Convective mass flux encodes information about the frequency and intensity of thunderstorms, and has been linked to the strength of the large-scale tropical circulation. Changes in convective mass flux under warming are an important, but uncertain, aspect of climate change. Here we build off recent work linking changes in mass flux to the clear-sky energy budget to show that convective mass fluxes decrease along isotherms at around 3%–5% <span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 <msup>\u0000 <mi>K</mi>\u0000 <mrow>\u0000 <mo>−</mo>\u0000 <mn>1</mn>\u0000 </mrow>\u0000 </msup>\u0000 </mrow>\u0000 <annotation> ${mathrm{K}}^{-1}$</annotation>\u0000 </semantics></math> under warming. We show that this constraint holds throughout the free-troposphere and across a hierarchy of models; from idealized radiative-convective equilibrium simulations to CMIP6 models. This decrease in convective mass flux with warming is driven by a stabilization of the lapse rate and can be captured with a simple analytical model. We also revisit previous work by Held and Soden (2006), https://doi.org/10.1175/jcli3990.1, who proposed a scaling for changes in the convective mass flux with warming. We show that the Held and Soden scaling does not capture inter-model spread in cloud-base mass flux changes under warming, and that their original verification was likely coincidental. Our work provides a quantitative constraint on changes in convective mass flux throughout the troposphere which can be derived from first principles, and which is verified across a hierarchy of models.</p>","PeriodicalId":14881,"journal":{"name":"Journal of Advances in Modeling Earth Systems","volume":"17 4","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024MS004695","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143856805","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":"Emergence of Self–Organization of Atmospheric Moist Convection, as Seen Through the Energy–Cycle in Wavelet Space","authors":"Jun-Ichi Yano, Robert S. Plant","doi":"10.1029/2024MS004517","DOIUrl":"https://doi.org/10.1029/2024MS004517","url":null,"abstract":"<p>The energy cycle of a convectively–organized system, as realized by a convective–scale idealized simulation, is analyzed in wavelet space. In the equilibrium state, most of the available potential energy that is generated by convective heating is immediately converted into kinetic energy by means of buoyancy forcing, consistent with the free–ride principle. In turn, most of the generated convective kinetic energy is manifest as gravity waves propagating away from convective centers. The kinetic energy of these small–scale gravity waves is transferred upscale by their own advective nonlinearities. Finally, a large–scale circulation generated by this “inverse cascade” drives the formation of an organized structure in the precipitation field.</p>","PeriodicalId":14881,"journal":{"name":"Journal of Advances in Modeling Earth Systems","volume":"17 4","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-04-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024MS004517","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143850993","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 Simple Approach to Represent Irrigation Water Withdrawals in Earth System Models","authors":"Bertrand Decharme, Maya Costantini, Jeanne Colin","doi":"10.1029/2024MS004508","DOIUrl":"https://doi.org/10.1029/2024MS004508","url":null,"abstract":"<p>The increasing demand for water, driven by population growth and agricultural expansion, underscores the need for accurate representation of irrigation in Earth System Models (ESMs). While a few current-generation ESMs incorporate irrigation, their representation of water withdrawals remains overly simplistic. These models typically source water solely from rivers and, in some cases, the ocean. This oversimplification can lead to inaccuracies in projecting water resources under climate change scenarios. This study presents a simple approach to integrate irrigation water withdrawals within the ISBA-CTRIP global hydrological system, which is the land surface model integrated into the French National Center for Meteorological Research's ESM. The methodology encompasses the withdrawal of water from both groundwater and conceptual small dams. A global data set is employed to impose irrigation water demands on cropland areas. Irrigation water is distributed according to the three main irrigation techniques: flood, sprinkler, and drip. This approach ensures the closure of the global water budget that is essential in climate simulations. The model was evaluated against satellite and in situ observations over the period 1971–2010, demonstrating some improvements in simulating the continental water cycle. Our findings underscore the necessity of incorporating comprehensive irrigation processes in ESMs to account for the intricate interconnections between irrigation practices, water resources, and climate. By enhancing the representation of anthropogenic water withdrawals in ESMs, this study aims at contributing to the development of more robust climate projections which could help building more informed water management strategies in the future.</p>","PeriodicalId":14881,"journal":{"name":"Journal of Advances in Modeling Earth Systems","volume":"17 4","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024MS004508","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143849193","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}
Cyril Morcrette, Tobias Cave, Helena Reid, Joana da Silva Rodrigues, Teo Deveney, Lisa Kreusser, Kwinten Van Weverberg, Chris Budd
{"title":"Scale-Aware Parameterization of Cloud Fraction and Condensate for a Global Atmospheric Model Machine-Learned From Coarse-Grained Kilometer-Scale Simulations","authors":"Cyril Morcrette, Tobias Cave, Helena Reid, Joana da Silva Rodrigues, Teo Deveney, Lisa Kreusser, Kwinten Van Weverberg, Chris Budd","doi":"10.1029/2024MS004651","DOIUrl":"https://doi.org/10.1029/2024MS004651","url":null,"abstract":"<p>Kilometer grid-length simulations over a variety of different locations worldwide are used as training data for a deep-learning model designed to predict clouds in a global climate model. The inputs to the neural network are profiles of temperature, humidity and pressure from the high-resolution model, averaged to the scale of the climate model. The outputs are profiles of cloud fraction and in-cloud liquid and ice water contents. The high-resolution data is coarse-grained to a range of sizes, allowing the model to learn how the cloud formation depends on the size of the area being considered. The machine-learned cloud fraction and cloud condensate scheme is coupled to a global climate model and used to run multi-year simulations where the clouds predicted by the neural-network are fully interacting with the rest of the model.</p>","PeriodicalId":14881,"journal":{"name":"Journal of Advances in Modeling Earth Systems","volume":"17 4","pages":""},"PeriodicalIF":4.4,"publicationDate":"2025-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024MS004651","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143849052","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}