Shi et al. (2025) An Accelerated Discrete Ordinate Method (ADOM) Developed for Scalar Radiative Transfer by Merging Adjacent Clear‐Sky Atmospheric Layers: Forward and Jacobians Derivation

⚠️ Warning: This summary was generated from the abstract only, as the full text was not available.

Identification

• Journal: Journal of Advances in Modeling Earth Systems
• Year: 2025
• Date: 2025-11-26
• Authors: Yi‐Ning Shi, Fuzhong Weng
• DOI: 10.1029/2025ms005136

Research Groups

Not specified in the abstract.

Short Summary

This study proposes an Accelerated Discrete Ordinate Method (ADOM) to significantly improve the computational efficiency of multi-layer radiative transfer simulations by applying the Discrete Ordinate Method only in scattering layers and merging adjacent clear-sky layers. ADOM maintains high accuracy, is applicable from visible to microwave spectra, and includes tangent linear and adjoint modules for accurate Jacobian computation in satellite radiance assimilation.

Objective

• To develop an Accelerated Discrete Ordinate Method (ADOM) that enhances the computational efficiency of multi-layer radiative transfer simulations while maintaining high accuracy.
• To develop tangent linear and adjoint modules for ADOM to accurately compute Jacobians of relevant parameters for satellite radiance assimilation, even for merged clear-sky layers.

Study Configuration

• Spatial Scale: Vertical atmospheric layers.
• Temporal Scale: Not specified in the abstract.

Methodology and Data

• Models used: Accelerated Discrete Ordinate Method (ADOM), Discrete Ordinate Method (DOM), non-scattering radiative transfer theory.
• Data sources: Evaluation against 128-stream DOM and finite difference results based on DOM.

Main Results

• ADOM enhances computational efficiency by applying DOM only in scattering layers and merging adjacent clear-sky layers using non-scattering radiative transfer theory.
• The merging process significantly reduces the number of layers, while fully accounting for the vertical structure of the Planck function and Rayleigh scattering single-scattering albedo.
• ADOM is applicable across the visible to microwave spectrum.
• Tangent linear and adjoint modules of ADOM were developed to compute Jacobians of all relevant parameters for satellite radiance assimilation.
• Jacobians of properties in each merged clear-sky layer can be accurately computed by constructing an adjoint module of the merging process.
• The accuracy of both forward and adjoint ADOM modules was evaluated against 128-stream DOM and finite difference results based on DOM.
• The computational efficiency gain of ADOM is directly influenced by the ratio of clear-sky layers to cloud layers; efficiency increases as the number of cloud layers decreases.
• In fully cloudy conditions, ADOM's runtime converges to that of DOM.

Contributions

• Introduction of ADOM, a novel hybrid radiative transfer approach that significantly improves computational efficiency for multi-layer simulations by intelligently combining DOM with non-scattering RT theory for clear-sky layers.
• Development of comprehensive tangent linear and adjoint modules for ADOM, enabling accurate Jacobian computations for satellite radiance assimilation, including for properties within merged clear-sky layers.
• Demonstration of ADOM's broad applicability across the visible to microwave spectral range.

Funding

Not specified in the abstract.

Citation

@article{Shi2025Accelerated,
  author = {Shi, Yi‐Ning and Weng, Fuzhong},
  title = {An Accelerated Discrete Ordinate Method (ADOM) Developed for Scalar Radiative Transfer by Merging Adjacent Clear‐Sky Atmospheric Layers: Forward and Jacobians Derivation},
  journal = {Journal of Advances in Modeling Earth Systems},
  year = {2025},
  doi = {10.1029/2025ms005136},
  url = {https://doi.org/10.1029/2025ms005136}
}