Investigating Smoke Aerosol Emission Coefficients Using MODIS Active Fire and Aerosol Products: A Case Study in the CONUS and Indonesia

摘要

Smoke aerosols released from biomass burning greatly influence air quality, weather, and climate. The total particulate matter (TPM) of smoke aerosols has been demonstrated to be a linear function of fire radiative energy (FRE) during a period of biomass burning via a smoke aerosol emission coefficient (Ce). However, it remains challenging to quantify Ce appropriately through satellite observations. In this study, an innovative approach was put forward to explore Ce by establishing the relationships between FRE and TPM in two regions, the CONtiguous United States and Indonesia. Specifically, we identified 584 isolated fire clusters and smoke plumes in the CONtiguous United States and 248 in Indonesia using Moderate Resolution Imaging Spectroradiometer natural color images, and then calculated FRE from Moderate Resolution Imaging Spectroradiometer active fire product and TPM from Moderate Resolution Imaging Spectroradiometer aerosol optical depth product for each fire-smoke matchup during Terra and Aqua overpasses. The relationships between TPM and FRE were constructed to determine Ce using an ordinary least squares regression. The results show that FRE and TPM are significantly correlated (r2 ≥ 0.63, p < 0.001) with the Ce varying across regions and fuel types. In the CONtiguous United States, forest Ce values are 21.3 and 34.1 g/MJ and savanna Ce values are 18.2 and 22.8 g/MJ for western and eastern regions, respectively; additionally, Ce is 20.9 g/MJ for grasslands and 5.0 g/MJ for shrublands. In Indonesia, Ce is 52.4 and 30.0 g/MJ for peatlands and forests, respectively. Overall, this study improves our understanding of Ce variations with fuel types and climate regions.