MATLAB Simulation of HITRAN Database for Gas Absorption Coefficient Calculation

Simulating gas absorption coefficients using MATLAB with the HITRAN database is a widely adopted spectroscopic analysis method, extensively applied in atmospheric science, remote sensing, and laser transmission fields. The HITRAN database provides detailed molecular absorption line parameters, and MATLAB enables efficient extraction and processing of this data to calculate gas absorption characteristics under specific conditions. The implementation approach primarily follows these steps: First, retrieve the required molecular absorption line data from the HITRAN database, including parameters such as line position, intensity, and linewidth. In MATLAB, use functions like `textscan` or `readtable` to parse HITRAN's structured text format, or implement custom binary readers for optimized data loading. Then, utilize these parameters along with environmental conditions like target gas temperature and pressure to build a computational model for absorption coefficients. This involves implementing algorithms for Voigt profile calculations to account for both Doppler and pressure broadening effects. Finally, compute the total absorption coefficient across specific spectral bands using numerical integration methods (e.g., `trapz` function) or line-by-line summation techniques. To enhance computational efficiency, optimize data reading strategies by using binary formats or pre-processing HITRAN data to reduce memory usage—consider implementing caching mechanisms with MATLAB's `matfile` for large datasets. To ensure simulation accuracy, incorporate spectral line broadening effects (Doppler and pressure broadening) using appropriate line shape functions and account for molecular interactions through collision broadening models. Leveraging MATLAB's powerful matrix operations (vectorized computations with operators like `.*` and `./`) and rich visualization capabilities (e.g., `plot` and `semilogy` functions), users can intuitively display gas absorption line characteristics as functions of wavelength, facilitating analysis and validation of simulation results. This methodology is applicable not only to single-gas absorption calculations but can also be extended to study spectroscopic properties of gas mixtures through weighted summation or iterative solvers for multi-component systems.