Expanding the Langley Calibration Method to Infrared Wavelengths: Modeling, Validation, and Applications

Aerosol optical depth (AOD) observations are usually focused on the visible wavelength. Recent studies highlight the potential of the infrared emission waveband in providing valuable insights for aerosol compositions (Ji et al., 2023). Expanding AOD measurements into the infrared spectrum offers an approach to enhance our understanding of aerosol properties. In this study, we use solar absorption spectra measured by Fourier Transform Infrared Spectrometer (FTIR) to obtain the infrared spectrum AOD using Langley method (Barreto et al., 2020) in several stations, including Ny-Ålesund (Arctic), Bremen (mid-latitude), and Palau (tropics). Integrating FTIR and sun-photometer observations, we obtain AOD in visible and infrared spetrum regions. This work highlights the possibility of extending traditional AOD retrieval method in visible wavelengths to a broad spectrum range.

 

Reference:

Ji, D., Palm, M., Ritter, C., Richter, P., Sun, X., Buschmann, M., and Notholt, J.: Ground-based remote sensing of aerosol properties using high-resolution infrared emission and lidar observations in the High Arctic, Atmos. Meas. Tech., 16, 1865–1879, https://doi.org/10.5194/amt-16-1865-2023, 2023.

Barreto, África, Omaira Elena García, Matthias Schneider, Rosa Delia García, Frank Hase, Eliezer Sepúlveda, Antonio Fernando Almansa, Emilio Cuevas, and Thomas Blumenstock. 2020. "Spectral Aerosol Optical Depth Retrievals by Ground-Based Fourier Transform Infrared Spectrometry" Remote Sensing 12, no. 19: 3148. https://doi.org/10.3390/rs12193148