Satellite Derived Biogenic Emissions

Vegetation and land use change play a significant but uncertain role in both air quality and climate. Biogenic non-methane volatile organic compounds (NMVOCs) emitted from plants are precursors to ozone, methane and secondary organic aerosols (SOA) which affect air quality and have both a warming influence (since ozone and methane are greenhouse gases) and a cooling influence (from the SOAs) on climate. Quantifying biogenic emissions is therefore necessary for both air quality and climate predictions. 

Biogenic emissions, such as isoprene are quickly converted by photolysis to other chemical species such as formaldehyde, which in turn is converted mainly to carbon monoxide (CO). Both formaldehyde and CO can be observed via satellite remote sensing. A new study by Worden et al., (2019) uses a Bayesian approach to estimate CO from biogenic sources by repartitioning CO fluxes obtained from inverse modeling of satellite CO observations from MOPITT. This study shows that estimated biogenic CO fluxes have similar spatial and seasonal variability compared to isoprene emission estimates from the inverse modeling of satellite formaldehyde observations from OMI. The repartitioned top-down estimates presented in the study provide an independent constraint for testing and improving models of biogenic emissions that are used for chemistry and climate predictions.

Biogenic CO fluxes
Figure 1. Biogenic CO fluxes from model predictions (left) and estimated biogenic CO fluxes from the repartitioned top-down total CO flux (right). Figure taken from Worden et al., ACP, 2019. Click for larger image.

Reference

Worden, H. M., Bloom, A. A., Worden, J. R., Jiang, Z., Marais, E., Stavrakou, T., Gaubert, B., and Lacey, F.: New Constraints on Biogenic Emissions using Satellite-Based Estimates of Carbon Monoxide Fluxes, Atmos. Chem. Phys., 19, 13569–13579, https://doi.org/10.5194/acp-19-13569-2019, 2019.