Downward transport of ozone due to convection near Manaus, Brazil

Estimating changes in greenhouse gas concentration in the troposphere can assist the development of more accurate numerical models designed to determine the radiative effects and influences on the climate. This study investigates the downward transport of ozone, a greenhouse gas, by the process of convection near Manaus, Brazil. Ozone data were recorded at a site located southwest of Manaus as part of the GOAmazon project. Ground-level ozone measurements were made during the months of February and March 2014. Infrared satellite imagery and legacy radar images were analyzed to determine convective storms associated with downward ozone transport. Satellite imagery is used to create two subcategories of spatial extent (large and small) as well as two subcategories of storm type (squall and individual). Average ozone enhancements due to convection (all categories of convection) on a 5-min resolution reached ~4 ppb and ranged from 2 to 11 parts per billion (ppb). The mean ozone change for large events was 7 ppb and for small events was 5 ppb. Large and small mesoscale convective events showed no significant difference (p=.0806) in the magnitude of ozone transported when a two sample t-test was run. Similar inconclusive results were found with the study of the type of storm (squall: 6 ppb, individual: 5 ppb, p-value: .5136). This new understanding of the magnitude of downward ozone transport within tropical convection will assist in the development of more accurate predictions of the climate.