The zonal structure of tropical O<sub>3</sub> and CO as observed by the Tropospheric Emission Spectrometer in November 2004 – Part 2: Impact of surface emissions on O<sub>3</sub> and its precursors

Abstract

Abstract. The impact of surface emissions on the zonal structure of tropical tropospheric ozone and carbon monoxide is investigated for November 2004 using satellite observations, in-situ measurements, and chemical transport models in conjunction with inverse-estimated surface emissions.Vertical ozone profiles from the Tropospheric Emission Spectrometer (TES) and ozone sonde measurements from the Southern Hemisphere Additional Ozonesondes (SHADOZ) network show elevated concentrations of ozone over Indonesia and Australia (60-70 ppb) in the lower troposphere against the backdrop of the well-known zonal "wave-one" pattern with ozone concentrations of (70-80 ppb) centered over the Atlantic . Observational evidence 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 The Troposphere (MOPITT) CO profiles (Jones et al., 2009). These a posteriori estimates, which were over a factor of 2 greater than climatological emissions, reduced differences between GEOSChem and TES ozone observations by 30-40% over IndoneCorrespondence to: K. Bowman (kevin.bowman@jpl.nasa.gov) sia. The response of the free tropospheric chemical state to the changes in these emissions is investigated for ozone, CO, NO x , and PAN. Model simulations indicate that ozone over Indonesian/Australian is sensitive to regional changes in surface emissions of NO x but relatively insensitive to lightning NO x . Over sub-equatorial Africa and South America, free tropospheric NO x was reduced in response to increased surface emissions potentially muting ozone production.

The zonal structure of tropical O<sub>3</sub> and CO as observed by the Tropospheric Emission Spectrometer in November 2004 – Part 1: Inverse modeling of CO emissions

“…Throughout the free troposphere over Indonesia and Australia O 3 increased in the model by as much as 10 ppb, reducing the maximum bias in the modeled O 3 distribution relative to TES by about 40%. In contrast, in the free troposphere over the tropical Southern Atlantic, Bowman et al (2009) found that the improvement in the modeled O 3 with the a posteriori emissions was modest, despite the large increases in surface emissions from sub-equatorial Africa, reflecting the greater influence of NO x from lightning on the budget of O 3 in this region.…”

“…Using a forward model simulation of GEOS-Chem with the O 3 precursor emissions from fuel combustion and biomass burning scaled by the regional scaling factors obtained in the CO inversion, Bowman et al (2009) showed that the a posteriori emissions provide an improved simulation of O 3 over Indonesia and Australia. Throughout the free troposphere over Indonesia and Australia O 3 increased in the model by as much as 10 ppb, reducing the maximum bias in the modeled O 3 distribution relative to TES by about 40%.…”

“…In a companion paper by Bowman et al (2009) the a posteriori emissions from the inversion are evaluated in the context of their impact on the modeled O 3 distribution. Using a forward model simulation of GEOS-Chem with the O 3 precursor emissions from fuel combustion and biomass burning scaled by the regional scaling factors obtained in the CO inversion, Bowman et al (2009) showed that the a posteriori emissions provide an improved simulation of O 3 over Indonesia and Australia.…”

“…In the study presented here we focus on the inverse modeling of the CO observations. In a companion paper by Bowman et al (2009) a detailed analysis is presented of the impact on tropical tropospheric O 3 of the changes in emissions of CO (and the implied changes in emissions of other O 3 precursors) inferred from the inversion analysis conducted here.…”

Evaluation of ACCMIP ozone simulations and ozonesonde sampling biases using a satellite-based multi-constituent chemical reanalysis

“…The reanalysis and multi-model mean commonly reveal distinct inter-hemispheric differences associated with a stronger downwelling across the tropopause and stronger emission sources of ozone precursors in the NH. The wave-1 pattern in the zonal ozone distribution in the tropics, with a minimum over the Pacific Ocean and maximum over the Atlantic (Thompson et al, 2003;Bowman et al, 2009;Ziemke et al, 2011), can also be commonly found in the reanalysis and the multi-model mean and was also suggested by Young et al (2013).…”