The Effect of Ice Particles on the Tropospheric Ozone Budget via Heterogeneous Conversion processes

Cirrus particles are ubiquitous throughout the mid- to upper troposphere and provide

reactive surfaces onto which trace gas species may become either attached or chemically processed,

thus modifying the chemical cycles active at high altitudes. Here we introduce two simple parameterizations

for the description of the micro-physical properties of ice particle fields into a global 3D

Chemistry Transport Model. We subsequently investigate the influence that the reversible loss of

HNO3 from the gas phase has on the tropospheric ozone budget. In contrast to previous studies

there is a modest increase in the global tropospheric ozone burden, where there are stark hemispheric

differences. By applying the EU-QUANTIFY 2050 aircraft emission scenarios using fixed

meteorology for 2006 we show that the influence of heterogeneous scavenging becomes less important

unless the available surface area upon which scavenging can occur would increase in the future.