Indirect forcings from emissions of NOx and CO: Is the location of emissions important?

摘要

Emissions of ozone precursors (NOx, CO and hydrocarbons) lead to formation of tropospheric ozone and radiative forcing (RF) of climate. In general the formation of ozone is dependent on the chemical/physical conditions where the emissions take place. We have used two global 3-D chemistry/transport models (CTMs) to estimate the changes in ozone and OH due to CO and NOx emissions in Europe and South-East Asia. Corresponding RFs are then calculated by two radiative transfer models. We find that the differences in the RF due to ozone changes to be 15-35% for changes in the location of CO emissions, while for NOx the difference is a factor 4.5 - 8. However, this result seems to be quite robust between the combination of models used in the study, which means that it could form the basis for deriving regional GWPs for the ozone precursors.