Organizations: State Key Laboratory of Physical Oceanography and Faculty of Information Science and Engineering, Ocean University of China, Qingdao 266100, China · School of Psychology and Neuroscience, University of Glasgow, Glasgow G12 8QQ, U.K.
Accurate modeling of sea ice concentration (SIC) evolution is essential for polar climate assessment and short?range sea ice prediction. Numerical and data-driven approaches constitute major foundations for SIC modeling, but the former often require complex parameterizations and substantial compu?tation, whereas the latter rarely encode physical dependencies explicitly. This study presents the Physics-Informed Hybrid Ice Model (PIHIM), a differentiable data-driven hybrid ice model for daily SIC evolution that organizes its network structure according to the physical dependencies encoded in the sea ice continuity equation and explicitly accounts for dynamical transport, ther?modynamically driven areal growth and loss, and unresolved local processes. PIHIM preserves the representation capacity of deep learning while providing a process-decomposed formulation of ice displacement, freeze-melt areal change, and local error closure. Two evaluation settings are adopted: reanalysis-forced simulation examines SIC evolution stability under reanalysis forcing, and forecast-forced prediction assesses short-range performance un?der forecast-forced conditions, with reanalysis and observational SIC serving as verification references. Results indicate enhanced ice-edge preservation and error-growth control in reanalysis?forced simulation, while PIHIM retains measurable short-range prediction skill under forecast-forced conditions. Our code will be made publicly available after the paper is accepted.
Figures & tables
Fig. 1: Conceptual overview. (a) SIC evolution is jointly driven by ice movement, freeze/melt processes, and local unresolved changes. (b) Black-box neural networks cannot explicitly attribute SIC changes to different physical processes. (c) PIHIM decomposes neural prediction into process-guided components for movement, freeze/melt, and local changes.
Fig. 2: PIHIM network overview. (a) The conceptual structure links the SIC continuity-equation decomposition to movement, freeze/melt processes, and local unresolved changes. (b) The implementation-level architecture presents the corresponding module inputs, outputs, and autoregressive rollout for multi-day prediction.
Category
Setting
Role
Evaluation setting
reanalysis-forced simulation
Setting defined in Section 4.1 for assessing SIC evolution under reanalysis forcing
Evaluation setting
forecast-forced prediction
Setting defined in Section 4.1 for assessing D1-D9 short-range prediction under forecast-forced conditions
AIFS provides air temperature and wind speed, RTOFS provides SST, and the sea ice velocity channel is set to zero
Observational verification
OSI SAF [ 54 ]
Satellite SIC for assessing whether the results depend on the GLORYS reference
Numerical reference
SEAS5 [ 17 ]
Serves as a contextual numerical reference rather than a task-equivalent baseline
TABLE I: Summary of experimental settings, data, metrics, and baselines
Fig. 3: Seasonal cycles of SIA/SIE in calendar-year integrations from 2022 to 2024
Fig. 4: SIA/SIE trajectories in multi-year continuous integration over the 2022-2024 test period
Fig. 5: Rapid ice-edge retreat case in reanalysis-forced simulation. Panels (a)-(d) correspond to D2, D6, D10, and D14 from the July 2, 2024 initialization.
Fig. 6: Rapid ice-edge expansion case in reanalysis-forced simulation. Panels (a)-(d) correspond to D2, D6, D10, and D14 from the October 16, 2024 initialization.
Fig. 7: GLORYS-verified ice-edge case in 99-case forecast-forced prediction. Panels (a)-(c) correspond to D3, D6, and D9 from the May 22, 2024 initialization.
Fig. 8: OSI SAF-verified ice-edge case in 99-case forecast-forced prediction. Panels (a)-(c) correspond to D3, D6, and D9 from the May 22, 2024 initialization.
Fig. 9: GLORYS-verified ice-edge comparison in SEAS5-intersection 25-case forecast-forced prediction. Panels (a)-(c) correspond to D3, D6, and D9 from the April 1, 2026 initialization.
Fig. 10: OSI SAF-verified ice-edge comparison in SEAS5-intersection 25-case forecast-forced prediction. Panels (a)-(c) correspond to D3, D6, and D9 from the April 1, 2026 initialization.
Accurate modeling of the daily evolution of sea ice concentration (SIC) is central to improving the credibility and operational forecasting capability of deep learning-based sea ice prediction. However, existing deep learning methods often couple the underlying sea ice evolution relationships and data errors within high-dimensional nonlinear mappings, making it difficult to construct a stable and verifiable evolution core and apply it reliably to practical forecasting. To address this issue, this study proposes a reanalysis-forecast dual-domain decoupled framework for learning sea ice evolution operators. The framework builds upon a lightweight physical baseline to generate daily evolution trajectories, employs a temporally constrained joint multi-lead compensation network to com?pensate for unresolved processes, and introduces an ice-mass?aware transport mechanism to suppress numerical dissipation. In the forecasting stage, the parameters of the base evolution core are fixed, while a lightweight variable-semantic adaptation mechanism calibrates inter-domain distributions and evolution responses, thereby separating forecast-domain errors from base evolution errors. Experiments show that the constructed base evolution core can accurately and stably simulate daily sea ice evolution at both short-term and annual scales under reanal?ysis forcing, and can be effectively transferred to the forecast domain through lightweight adaptation, achieving stable prac?tical forecasting capability while preserving the base evolution structure. The source code will be made publicly available at https://github.com/zhangmaqun65535/SNM upon acceptance of this manuscript.
Maqun Zhang, Feng Gao, Wankun Chen +3
State Key Laboratory of Physical Oceanography and Faculty of Information Science and Engineering, Ocean University of China, Qingdao 266100, China · School of Psychology and Neuroscience, University of Glasgow, Glasgow G12 8QQ, U.K.
Greenland iceberg discharge exhibits complex nonlinear dynamics with limited observability, challenging traditional predictive models. We present a Hybrid NARX-LLM framework that combines a nonlinear autoregressive model with exogenous inputs (NARX) and a large language model (LLM) for residual correction. We further propose a Physics-Informed Prompt (PIP) method that transforms unstructured physical knowledge into structured prompts for zero-shot in-context reasoning. The primary objective is to explore the corrective potential of this framework for modeling Greenland iceberg discharge, rather than merely optimizing predictive accuracy. The NARX component captures intrinsic temporal dependencies, while the LLM, guided by PIP, encodes glacier dynamics and environmental drivers and perceives key trend patterns to correct systematic prediction errors. This integration allows the model to reason about unmodeled factors and produce interpretable residuals, enhancing overall predictive accuracy. Applied to Greenland iceberg discharge time series, our approach addresses extreme events that are difficult to predict due to rare variations and nonstationary trends, a limitation often overlooked by traditional methods. By fusing structured time-series modeling with knowledge-driven foundation AI, the framework offers a scalable and interpretable pathway to bridge data-limited climate forecasting with physics-informed LLM reasoning. The code is available.
Yiquan Gao, Duohui Xu
1Heriot-Watt University. · 2StudioYG. · This work was completed before the first author’s affiliation with Heriot-Watt University and was conducted entirely independently of the institution.
Sea ice forecasts are issued several days ahead, allowing errors to accumulate while new, often sparse sea ice concentration (SIC) observations become available. We find that fixed-propagation errors concentrate near structured, high-gradient ice edges, whereas homogeneous interiors require limited propagation, suggesting that propagation distance should be state dependent. We therefore introduce ECHO (Evidence-guided Correction with Heterogeneous prOpagation), where ECHO-Scale adapts propagation distance while preserving correction geometry, and ECHO-Delta learns a bounded residual around fixed propagation. Across all 96 standard evaluation settings spanning diverse priors, observation times, sparsity levels, geometries, and noise conditions, both outperform fixed propagation. ECHO-Delta achieves the best average accuracy, while ECHO-Scale is more robust to geometry shifts. Code is available at https://github.com/yingtian22/TAKING-A-SECOND-LOOK.
Tianshuo Zhang, Xianglei Xing, Aowen Yang +4
College of Intelligent Systems Science and Engineering, Harbin Engineering University, Harbin 150001, China