Quantifying the impact of African biomass burning on the remote Atlantic atmosphere

Pollution emitted in the tropics can a ff ect the troposphere in both hemispheres resulting in a global influence. Africa covers 20% of the world's landmass including both hemispheres from north of 30 o N to south of 30 o S. Much of Africa's pollution is emitted within 15 o of the equator and longer-lived trace gases are transported to remote areas of the troposphere, where they alter the chemical composition, oxidative capacity, and the radiative budget of the global background atmosphere. Biomass burning in Africa has a strong seasonal cycle: late November to early March in the African northern hemisphere, and July to October in the African southern hemisphere. Africa is the largest source of CO from biomass burning globally; the Global Fires Emissions Database (GFED) estimates that over 50% of global biomass burning CO comes from Africa (1120 Tg C yr -1 1997-2016), with savannah as the dominant fuel source. NASA ATom flights sampled outflow from Africa a number of days downwind from emission in the Atlantic in August 2016, February 2017, October 2017 and May 2018. We use a Lagrangian Particle Dispersion model to calculate the surface influence for these observations and evaluate the highly uncertain emissions inventories for a variety of trace gases, leveraging many of the 300+ trace gases measured during ATom.