Publications

Lu, XM; Zhang, XY; Li, FJ; Cochrane, MA (2019). Investigating Smoke Aerosol Emission Coefficients Using MODIS Active Fire and Aerosol Products: A Case Study in the CONUS and Indonesia. JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES, 124(6), 1413-1429.

Abstract
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 (C-e). However, it remains challenging to quantify C-e appropriately through satellite observations. In this study, an innovative approach was put forward to explore C-e 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 C-e using an ordinary least squares regression. The results show that FRE and TPM are significantly correlated (r(2) >= 0.63, p < 0.001) with the C-e varying across regions and fuel types. In the CONtiguous United States, forest C-e values are 21.3 and 34.1 g/MJ and savanna C-e values are 18.2 and 22.8 g/MJ for western and eastern regions, respectively; additionally, C-e is 20.9 g/MJ for grasslands and 5.0 g/MJ for shrublands. In Indonesia, C-e is 52.4 and 30.0 g/MJ for peatlands and forests, respectively. Overall, this study improves our understanding of C-e variations with fuel types and climate regions. Plain Language Summary Hundreds to thousands of fire events happen yearly in both the temperate climate of the CONtiguous United States and tropical Indonesia. These fires are major sources of air pollution, greenhouse gases, and aerosols, which greatly affect regional climate, weather, air quality, and human health. It is therefore important to estimate the amounts of particulate emissions released during these fires. We propose here a simple but robust method for accurately estimating fire particulate emissions from satellite observations that enables assessing variations by climatic region and land cover type. By analyzing Moderate Resolution Imaging Spectroradiometer-based active fire and aerosol products, we found that, for a given fire size, (1) forest fire particulate emission levels are larger than those from grasslands, savannas, and shrublands in the CONtiguous United States; (2) particulate emissions from peatland fires are substantially greater than those from forest fires in Indonesia; and (3) forest fire particulate emissions are greater in Indonesia than the CONtiguous United States as a whole. The results from this study improve our understanding of fire emissions by climatic region and land cover type that can better explain regional impacts on environmental conditions and human health.

DOI:
10.1029/2018JG004974

ISSN:
2169-8953