Measurement of tropospheric ozone by thermal emission spectroscopy

A new technique has been developed for the remote sensing of tropospheric ozone. In this technique the thermal radiation from ozone is measured against the cold background blackbody emission of clouds using ground-based FTIR spectroscopy. Preliminary measurements obtained in the springtime at Peterborough, Ontario, using this new technique, have indicated an average tropospheric ozone mixing ratio of 50 ± 7 ppbv within a 2.7 km layer from the surface for air flowing from a heavily industrialized and highly urbanized region. Ozone concentrations of this magnitude are in accordance with the amounts obtained for moderately polluted, springtime air using traditional in situ measurement techniques. The greenhouse radiation flux associated with this amount of ozone was estimated to be 0.61 W m−2 ± 13%. Since there are few techniques available for the remote sensing of tropospheric air pollutants, this new technique could be a potentially valuable development.