Satellite observations and modelling of hydrogen cyanide in the Earth's atmosphere

Hydrogen cyanide (HCN) is one of the most abundant cyanidespresent in the global atmosphere, and is a tracer of biomass burning, especially forpeatland wildfires. In this work we present observations of HCN during the 2015Indonesian peatland fires from the IASI (Infrared Atmospheric Sounding Interfer-ometer) satellite instrument. We also investigate HCN variability using an updatedversion of the TOMCAT three-dimensional (3-D) chemical transport model (CTM),which is evaluated using HCN profiles measured by the Atmospheric ChemistryExperiment Fourier Transform Spectrometer (ACE-FTS) and FTIR ground-basedinstruments in the NDACC (Network for the Detection of Atmospheric CompositionChange) network. Here, we compare model simulations with the IASI measurements over Indonesia