A cloud-ozone data product from Aura OMI and MLS satellite measurements

摘要

Ozone within deep convective clouds is controlled by several factorsinvolving photochemical reactions and transport. Gas-phase photochemicalreactions and heterogeneous surface chemical reactions involving ice, waterparticles, and aerosols inside the clouds all contribute to the distributionand net production and loss of ozone. Ozone in clouds is also dependent onconvective transport that carries low-troposphere/boundary-layer ozone andozone precursors upward into the clouds. Characterizing ozone in thick cloudsis an important step for quantifying relationships of ozone with troposphericHO, OH production, and cloud microphysics/transportproperties. Although measuring ozone in deep convective clouds from eitheraircraft or balloon ozonesondes is largely impossible due to extrememeteorological conditions associated with these clouds, it is possible toestimate ozone in thick clouds using backscattered solar UV radiationmeasured by satellite instruments. Our study combines Aura Ozone MonitoringInstrument (OMI) and Microwave Limb Sounder (MLS) satellite measurements togenerate a new research product of monthly-mean ozone concentrations in deepconvective clouds between 30° S and 30° N for October 2004–April 2016.These measurements represent mean ozone concentration primarilyin the upper levels of thick clouds and reveal key features of cloud ozoneincluding: persistent low ozone concentrations in the tropical Pacific of ∼ 10 ppbv or less; concentrations of up to 60 pphv or greaterover landmass regions of South America, southern Africa, Australia, andIndia/east Asia; connections with tropical ENSO events; andintraseasonal/Madden–Julian oscillation variability. Analysis of OMI aerosolmeasurements suggests a cause and effect relation between boundary-layerpollution and elevated ozone inside thick clouds over landmass regionsincluding southern Africa and India/east Asia.