Decoding the Relationship Between Cloud Electrification, Downdrafts, and Surface Ozone in the Amazon Basin

Summary

The relationship between the electric field of storms and surface ozone (O3) levels in the Amazon Tall Tower Observatory (ATTO) region was investigated. Our findings reveal that surface ozone concentrations increase with the rise in the absolute electric field (|Ez|) of clouds. This phenomenon is linked to the amplification of downdraft magnitudes, which are similarly associated with the |Ez|. Detailed analysis also indicated that stronger downdrafts correlate with higher surface ozone levels. Consequently, the |Ez|-downdrafts-O3 interaction forms a coupled system, influenced by the strength of convective clouds. Notably, a more significant effect is observed when the |Ez| surpasses the threshold of lightning activity, leading to an increment of up to 5 ppbv in surface O3. This increment was shown to be independent of downdraft intensity or cloud height, relating solely to the impact of electrical activity. Based on the observational data, a novel parameterization was developed to predict surface ozone concentrations during storms, effectively incorporating the proportional impact of cloud electrification and downdrafts. This phenomenological model provides a robust tool for understanding and forecasting ozone dynamics in storm events in the Amazon rainforest, highlighting the intricate interplay between cloud electricity, downdrafts, and air chemistry in tropical convective storms.