Effect of sulfate aerosol on tropospheric NO_x and ozone budgets: Model simulations and TOPSE evidence

Abstract

[1] The distributions of NO x and O 3 are analyzed during TOPSE (Tropospheric Ozone Production about the Spring Equinox). In this study these data are compared with the calculations of a global chemical/transport model (Model for OZone And Related chemical Tracers (MOZART)). Specifically, the effect that hydrolysis of N 2 O 5 on sulfate aerosols has on tropospheric NO x and O 3 budgets is studied. The results show that without this heterogeneous reaction, the model significantly overestimates NO x concentrations at high latitudes of the Northern Hemisphere (NH) in winter and spring in comparison to the observations during TOPSE; with this reaction, modeled NO x concentrations are close to the measured values. This comparison provides evidence that the hydrolysis of N 2 O 5 on sulfate aerosol plays an important role in controlling the tropospheric NO x and O 3 budgets. The calculated reduction of NO x attributed to this reaction is 80 to 90% in winter at high latitudes over North America. Because of the reduction of NO x , O 3 concentrations are also decreased. The maximum O 3 reduction occurs in spring although the maximum NO x reduction occurs in winter when photochemical O 3 production is relatively low. The uncertainties related to uptake coefficient and aerosol loading in the model is analyzed. The analysis indicates that the changes in NO x due to these uncertainties are much smaller than the impact of hydrolysis of N 2 O 5 on sulfate aerosol. The effect that hydrolysis of N 2 O 5 on global NO x and O 3 budgets are also assessed by the model. The results suggest that in the Northern Hemisphere, the average NO x budget decreases 50% due to this reaction in winter and 5% in summer. The average O 3 budget is reduced by 8% in winter and 6% in summer. In the Southern Hemisphere (SH), the sulfate aerosol loading is significantly smaller than in the Northern Hemisphere. As a result, sulfate aerosol has little impact on NO x and O 3 budgets of the Southern Hemisphere.

Simulation of Mexico City plumes during the MIRAGE-Mex field campaign using the WRF-Chem model

“…In addition, there is also an important pathway to convert NO x to NO y through the hydrolysis of N 2 O 5 on the sulfate aerosols. However, this later reaction becomes important only when sulfate aerosol loading is high and solar radiation is low (e.g., at high latitudes or during nighttime) (Tie et al, 2003b(Tie et al, , 2005. In Mexico City, the later reaction to convert NO x to NO y can be neglected.…”

“…The version of the model, as used in the present study, includes on-line calculation of dynamical inputs (winds, temperature, boundary layer, clouds etc. ), transport (advective, convective, and diffusive), dry deposition (Wesely et al, 1989), gas phase chemistry, radiation and photolysis rates (Madronich and Flocke, 1999;Tie et al, 2003a), and surface emissions (including an on-line calculation of biogenic emission). The ozone formation chemistry is represented in the model by (West et al, 2004) 2.25×10 5 1.77×10 6 2.05×10 5 1.43×10 6 TIE 0.14×10 5 1.73×10 6 0.74×10 5 1.57×10 6 This study * 2.50×10 5 2.39×10 6 1.69×10 5 1.23×10 6 * The emissions include other smaller cities outside of Mexico within in 1000×1000 km domain.…”

Upgrading photolysis in the p-TOMCAT CTM: model evaluation and assessment of the role of clouds

“…The reaction rates for all species were updated in March 2005 according to the latest IUPAC (Atkinson et al, 2005) and other published rates. We also include the heterogeneous removal of N 2 O 5 on sulfate aerosol following the method in the MOZART model (Tie et al, 2003a), with the addition of a more detailed calculation of the uptake coefficient based on Evans and Jacob (2005). Offline monthly mean aerosols were taken from the GOCART model output (Chin et al, 2002) to be used as input for this calculation.…”

The sensitivity of Western European NO2 columns to interannual variability of meteorology and emissions: a model—GOME study

“…Lightning emissions of NO x are based on the parameterization of Price and Rind (1992) as implemented by Stockwell et al (1999) with an average emission for 1996-2000 of 3.9 Tg (N ) per year. The modeled heterogeneous removal of N 2 O 5 on sulfate aerosol is based on that in the MOZART model as described in Tie et al (2003). Offline sulfate aerosol data were taken from the GOCART model (Chin et al, 2002) and an uptake coefficient of 0.04 was assumed.…”