A general model for sun and sky glint removal in above-water optical radiometry: mathematical description and Python code

The 3C model for removing glint from above-water optical radiometry is updated to remove a number of limitations. The expression of the aquatic reflectance, formerly based on the model proposed by Albert and Mobley, neglected the effect of the relative azimuth to the sun’s location. The new model “3C-O25” incorporates an adaptation of the O25 model, a physically based approach for aquatic bidirectional studies and IOP retrieval that adequately accounts for the sun-view geometry and bio-optics. The former code backend, implemented in the deprecated Theano library, has been replaced with a NumPy implementation that prioritizes computational and I/O efficiency, making it suitable for integration into large data processing pipelines. Model, documentation and examples are available as open source on a GitHub repository, providing the community with a robust tool for accurate above-water radiometry processing across a wide range of atmospheric and aquatic conditions. The 3C model framework has been updated with state-of-the-art physical models. Results validate usage of the model in a wide range of glint conditions. The model has been completely recoded in Python/NumPy. An Open-Access GitHub repository has been created.