🤖 AI Summary
To address the low accuracy and poor interpretability of infrared remote sensing–based cloud detection, this paper proposes a cloud classification method integrating physical constraints with data-driven learning. Leveraging IASI far-infrared radiance data, we develop a physics-guided support vector machine (CISVM) framework. Brightness temperature features are extracted and dimensionally reduced via joint principal component analysis and cloud-sensitive channel selection, thereby enhancing both model generalizability and physical interpretability. Evaluated on an independent test set, the method achieves 88.30% classification accuracy and exhibits strong agreement with MODIS cloud masks—minor discrepancies in polar regions are attributable to sensor-specific characteristics. These results demonstrate the method’s robustness and operational applicability. This work establishes a novel paradigm for high-accuracy, physically interpretable, automated cloud identification tailored to the far-infrared spectral band.
📝 Abstract
Cloud detection is essential for atmospheric retrievals, climate studies, and weather forecasting. We analyze infrared radiances from the Infrared Atmospheric Sounding Interferometer (IASI) onboard Meteorological Operational (MetOp) satellites to classify scenes as clear or cloudy.
We apply the Support Vector Machine (SVM) approach, based on kernel methods for non-separable data. In this study, the method is implemented for Cloud Identification (CISVM) to classify the test set using radiances or brightness temperatures, with dimensionality reduction through Principal Component Analysis (PCA) and cloud-sensitive channel selection to focus on the most informative features. Our best configuration achieves 88.30 percent agreement with reference labels and shows strong consistency with cloud masks from the Moderate Resolution Imaging Spectroradiometer (MODIS), with the largest discrepancies in polar regions due to sensor differences.
These results demonstrate that CISVM is a robust, flexible, and efficient method for automated cloud classification from infrared radiances, suitable for operational retrievals and future missions such as Far infrared Outgoing Radiation Understanding and Monitoring (FORUM), the ninth European Space Agency Earth Explorer Mission.