Ozone measurements from eyewall transects of two Atlantic tropical cyclones

Measurements of ozone (O-3) concentrations obtained during aircraft eyewall crossings of Tropical Cyclones Floyd (September 1999) and Georges (September 1998) by NOAA P-3 hurricane research aircraft showed marked changes between the intensifying and weakening stages of the storms' life cycles. Renewed deepening appeared to be underway near landfall of both storms. During intensification, ozone levels indicated that air either descended from an altitude <1 km above flight level or was strongly diluted with low-O-3 eyewall air. During weakening, Ozone concentrations were low throughout the eye and eyewall, consistent with the eye's being filled with boundary layer air.