Impact of surface emissions to the zonal variability of tropical tropospheric ozone and carbon monoxide for november 2004 Impact of surface emissions

Abstract

Impact of surface emissions to the zonal variability of tropical tropospheric ozone and carbon monoxide for november 2004. Abstract The chemical and dynamical processes governing the zonal variability of tropical tropo-spheric ozone and carbon monoxide are investigated for November 2004 using satellite observations, in-situ measurements, and chemical transport models in conjunction with inverse-estimated surface emissions. Vertical ozone profile estimates from 5 the Tropospheric Emission Spectrometer (TES) and ozone sonde measurements from the Southern Hemisphere Additional Ozonesondes (SHADOZ) network show the so-called zonal "wave-one" pattern, which is characterized by peak ozone concentrations (70-80 ppb) centered over the Atlantic, as well as elevated concentrations of ozone over Indonesia and Australia (60-70 ppb) in the lower troposphere. Observational ev-10 idence from TES CO vertical profiles and Ozone Monitoring Instrument (OMI) NO 2 columns point to regional surface emissions as an important contributor to the elevated ozone over Indonesia. This contribution is investigated with the GEOS-Chem chemistry and transport model using surface emission estimates derived from an optimal inverse model, which was constrained by TES and Measurements Of Pollution In 15 The Troposphere (MOPITT) CO profiles (Jones et al., 2007). These a posteriori estimates , which were over a factor of 2 greater than climatological emissions, reduced differences between GEOS-Chem and TES ozone observations by 30-40% and led to changes in GEOS-Chem upper tropospheric ozone of up to 40% over Indonesia. The remaining residual differences can be explained in part by upper tropospheric ozone 20 produced from lightning NO x in the South Atlantic. Furthermore, model simulations from GEOS-Chem indicate that ozone over Indonesian/Australian is more sensitive to changes in surface emissions of NO x than ozone over the tropical Atlantic.