Forward modelling low-spectral-resolution Cassini/CIRS observations of Titan

Area of Science:

• Planetary Science
• Atmospheric Science
• Spectroscopy

Background:

• Cassini spacecraft's Composite InfraRed Spectrometer (CIRS) collected 8.4 million spectral observations of Titan.
• A significant portion of these low-spectral-resolution (SR) observations remain underutilized for atmospheric analysis due to data volume and spectral feature complexity.

Purpose of the Study:

• To develop and validate computationally efficient forward modeling techniques for the vast CIRS low-SR dataset of Titan.
• To enable more comprehensive analysis of Titan's atmospheric composition using previously underused spectral data.

Main Methods:

• Application of a computationally efficient correlated-k method for forward modeling CIRS FP3/4 nadir low-SR observations.
• Quantification of wavenumber-dependent forward modeling errors for improved retrieval accuracy.
• Demonstration of an optimized line-by-line method for higher accuracy when needed.

Main Results:

• Accurate forward modeling of CIRS low-SR Titan observations was achieved using the correlated-k method.
• Wavenumber-dependent forward modeling errors were quantified, providing crucial data for future atmospheric retrievals.
• The optimized line-by-line method offers a viable alternative for high-accuracy modeling, with reduced computation time.

Conclusions:

• The developed forward modeling techniques significantly enhance the usability of the extensive CIRS low-SR dataset for Titan atmospheric studies.
• This work paves the way for more rigorous and comprehensive analysis of Titan's atmospheric composition.
• Efficient modeling strategies are crucial for unlocking the full scientific potential of large planetary science datasets.