Influences of Deep Convection on the Distribution of Upper Tropospheric Ozone as Determined from NOAA20 OMPS, DSCOVR EPIC, and Aura OMI/MLS Satellite Measurements

Ozone within deep convective clouds is controlled by several factors involving photochemical reactions and transport. Gas-phase photochemical reactions and heterogeneous surface chemical reactions involving ice, water particles, and aerosols inside the clouds all contribute to the distribution and net production and loss of ozone. Ozone in clouds is also dependent on convective transport that lifts low troposphere/boundary layer ozone and ozone precursors up into the clouds. Characterizing ozone in thick clouds is an important step for quantifying relationships of ozone with tropospheric H₂O, OH production, and cloud microphysics/transport properties. Although measuring ozone in deep convective clouds from either aircraft or balloon ozonesondes is largely impossible due to extreme meteorological conditions associated with these clouds, it is possible to estimate ozone in thick clouds using backscattered solar UV radiation measured from satellite instruments. Our study considers measurements from multiple satellite instruments for determining ozone concentrations in deep convective clouds beginning in October 2004. These satellite instruments include: (1) the NOAA-20 Ozone Mapping Profiler Suite (OMPS) Nadir Mapper; (2) the EPIC instrument onboard the DSCOVR satellite; (3) the Aura Ozone Monitoring Instrument (OMI). Data from Microwave Limb Sounder (MLS) are used to constrain stratospheric ozone columns. UV measurements are mostly sensitive to ozone concentrations in the upper levels of thick clouds. Our study reveals some key features of ozone in clouds including persistent low ozone values in the tropical Pacific with concentration of ~10 ppbv or less, and higher ozone values of up to 60 ppbv or greater over landmass regions of South America, southern Africa, Australia, and India/east Asia. A combination of these satellite measurements describe variability in ozone concentration in the thick convective clouds from hourly/daily to inter-annual timescales.