Impacts of aerosol scattering on the short-wave infrared satellite observations of CO2

Abstract:

Atmospheric aerosols and carbon dioxide (CO₂), as two key factors driving the global climate change, have earned enormous attention from scientist around the world. One challenge for the satellite measurements of CO₂ using this SWIR wavelength range (~1.6μm) is the impact of multiple scattering by aerosols and cirrus. Since the rapid economic growth and associated increase in fossil fuel consumption have caused serious particulate pollution in many regions of China, remote sensing of CO₂ using SWIR band in China needs to pay more attention to the scattering properties of aerosol particles and the multiple scattering. Considering the complexity of morphological and chemical properties, aerosol particles are grouped based on a large number of TEM/SEM images, and then their scattering properties at 1.6μm band are calculated by the T-matrix method and GMM method. In this study, the Monte Carlo method is used to solve the multiple scattering problem by simulating photons transport in the scattering media. We combined this multiple scattering model with the LBLRTM as a forward radiative transfer model for studying the impact of aerosol scattering on the satellite observations of CO₂ using SWIR band. Finally, based on the GOCART aerosol component products, AERONET aerosol size distribution products, CALIPSO aerosol profile products, and MODIS aerosol optical depth and surface albedo products, the monthly variability of errors in CO₂ concentrations over China were calculated and analyzed. The results indicate that CO₂ concentrations are overestimated in western regions of China, especially in desert areas (a maximum of ~7.08%), and those are underestimated in eastern regions (a minimum of ~-6.9%).