Evaluation of CO and HCN emissions from Indonesia during 2015 wildfires season using satellite observation.

Indonesia is seasonally affected by intense fire events, often driven by El Ni\ no events. These events release substantial amounts of carbon stored in the soil as peat into the atmosphere, affecting the air quality and the atmospheric composition of the region and on a global scale. During the 2015 El Ni\ no event, a strong enhancement of Indonesian peat fires was observed from space by the Infrared Atmospheric Sounding Interferometer (IASI) instrument monitoring atmospheric carbon monoxide (CO) and hydrogen cyanide (HCN) concentration. These satellite observations are used to estimate CO and HCN fire emissions using the INVICAT inverse modelling framework. The derived emissions in Indonesia are found to be substantially different from the Global Fire Emissions Database (GFEDv4.1s) emission inventory, highlighting uncertainties in its estimates. IASI-based fire emissions capture observed variations more accurately, thus atmospheric composition satellite observations have a high potential to constrain the actual emission inventories whose estimates are based only on fire information such as fire counts, fire radiative power and burned area.