IMPACT, the LLNL 3‐D global atmospheric chemical transport model for the combined troposphere and stratosphere: Model description and analysis of ozone and other trace gases

Rotman, D.; Atherton, C. S.; Bergmann, D.; Cameron-Smith, P. J.; Chuang, Catherine C.; Connell, Peter S.; Dignon, J.; Franz, Amy; Grant, K. E.; Kinnison, Douglas E.; Molenkamp, C.R.; Proctor, Deanne D.; Tannahill, J.

doi:10.1029/2002jd003155

Cited by 115 publications

(118 citation statements)

References 145 publications

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“…GEOS operational meteorological products have been widely used for off-line CTM applications including by the University of Maryland (UMD) CTM (Allen et al, 1996), GEOS-Chem , Global Modeling Initiative (GMI) CTM (Douglass et al, 1999(Douglass et al, , 2004, Integrated Massively Parallel Atmospheric Chemical Transport (IM-PACT) model (Rotman et al, 2004), MOZART (Emmons et al, 2010), CAM-Chem (Lamarque et al, 2012), and the GEOS CTM . Chemical transport simulations can also be performed online within the GEOS-5 GCM (Colarco et al, 2010;Oman and Douglass, 2014;Long et al, 2015;Strode et al, 2015;Li et al, 2016).…”

Section: Geos-5 Gcmmentioning

confidence: 99%

Errors and improvements in the use of archived meteorological data for chemical transport modeling: an analysis using GEOS-Chem v11-01 driven by GEOS-5 meteorology

Keller

Jacob

et al. 2018

Geosci. Model Dev.

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Abstract. Global simulations of atmospheric chemistry are commonly conducted with off-line chemical transport models (CTMs) driven by archived meteorological data from general circulation models (GCMs). The off-line approach has the advantages of simplicity and expediency, but it incurs errors due to temporal averaging in the meteorological archive and the inability to reproduce the GCM transport algorithms exactly. The CTM simulation is also often conducted at coarser grid resolution than the parent GCM. Here we investigate this cascade of CTM errors by using 222 Pb and 7 Be against aerosol deposition are affected by 5-10 %. The lost vertical transport in the coarse-resolution GEOS-Chem simulation can be partly restored by recomputing the convective mass fluxes at the appropriate resolution to replace the archived convective mass fluxes and by correcting for bias in the spatial averaging of boundary layer mixing depths.

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Section: Geos-5 Gcmmentioning

confidence: 99%

Errors and improvements in the use of archived meteorological data for chemical transport modeling: an analysis using GEOS-Chem v11-01 driven by GEOS-5 meteorology

Keller

Jacob

et al. 2018

Geosci. Model Dev.

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“…We use an aerosol chemistry version of the Integrated Massively Parallel Atmospheric Chemical Transport (IMPACT) model (Rotman et al, 2004;Liu et al, 2005;Feng and Penner, 2007;Ito et al, 2009) as a framework for this study. The model is driven by assimilated meteorological fields for the year of 2001 from the Goddard Earth Observation System (GEOS) of the NASA Global Modeling and Assimilation Office (GMAO).…”

Section: Atmospheric Aerosol Chemistry Transport Modelmentioning

confidence: 99%

Role of dust alkalinity in acid mobilization of iron

2010

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Abstract. Atmospheric processing of mineral aerosols by acid gases (e.g., SO 2 , HNO 3 , N 2 O 5 , and HCl) may play a key role in the transformation of insoluble iron (Fe in the oxidized or ferric (III) form) to soluble forms (e.g., Fe(II), inorganic soluble species of Fe(III), and organic complexes of iron). On the other hand, mineral dust particles have a potential of neutralizing the acidic species due to the alkaline buffer ability of carbonate minerals (e.g., CaCO 3 and MgCO 3 ). Here we demonstrate the impact of dust alkalinity on the acid mobilization of iron in a three-dimensional aerosol chemistry transport model that includes a mineral dissolution scheme. In our model simulations, most of the alkaline dust minerals cannot be entirely consumed by inorganic acids during the transport across the North Pacific Ocean. As a result, the inclusion of alkaline compounds in aqueous chemistry substantially limits the iron dissolution during the long-range transport to the North Pacific Ocean: only a small fraction of iron (<0.2%) dissolves from hematite in the coarse-mode dust aerosols with 0.45% soluble iron initially. On the other hand, a significant fraction of iron (1-2%) dissolves in the fine-mode dust aerosols due to the acid mobilization of the iron-containing minerals externally mixed with carbonate minerals. Consequently, the model quantitatively reproduces higher iron solubility in smaller particles as suggested by measurements over the Pacific Ocean. It implies that the buffering effect of alkaline content in dust aerosols might help to explain the inverse relationship between aerosol iron solubility and particle size. We also demonstrate that the iron solubility is sensitive to the chemical specification of iron-containing minerals in dust. Compared with the dust sources, soluble iron from combustion sources contributes to a relatively marginal effect for deCorrespondence to: A. Ito (akinorii@jamstec.go.jp) position of soluble iron over the North Pacific Ocean during springtime. Our results suggest that more comprehensive data for chemical specificity of iron-rich dust is needed to improve the predictive capability for size-segregated soluble iron particles.

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“…A global aerosol and chemistry transport model, the University of Michigan (UMICH) version of the Lawrence Livermore National Laboratory (LLNL) IMPACT model [Liu and Penner, 2002;Feng et al, 2004;Rotman et al, 2004;Liu et al, submitted, 2005], was used as the framework for this study. The spatial resolution of the IMPACT model is 2° latitude by 2.5° longitude in the horizontal, with 26 layers in the vertical from the surface to 0.1 hPa (the mean pressure levels are 994,971,930,875,813,745,675,605,537,472,410,353,302,258,220,187,158,133,112,94.1,79.3,67.0,56.7,37.7,14.3,and 2.64 hPa).…”

Section: Global Aerosol and Chemistry Transport Modelmentioning

confidence: 99%

“…The cumulus mass flux and convective cloud detrainment used in the scheme are derived from the DAO meteorological fields. A full description of the transport and deposition schemes is given in Rotman et al [2004] for the original IMPACT model. [Penner et al, 1994].…”

Section: Global Aerosol and Chemistry Transport Modelmentioning

confidence: 99%

Heterogeneous Chemistry: Understanding Aerosol/Oxidant Interactions

Penner¹

2005

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Abstract. Global radiative forcing of nitrate and ammonium aerosols has mostly been estimated from aerosol concentrations calculated at thermodynamic equilibrium or using approximate treatments for their uptake by aerosols. In this study, a more accurate hybrid dynamical approach (DYN) was used to simulate the uptake of nitrate and ammonium by aerosols and the interaction with tropospheric reactive nitrogen chemistry in a threedimensional global aerosol and chemistry model, IMPACT, which also treats sulfate, sea salt and mineral dust aerosol. 43% of the global annual average nitrate aerosol burden, 0.16 TgN, and 92% of the global annual average ammonium aerosol burden, 0.29 TgN, exist in the fine mode (D<1.25µm) that scatters most efficiently. Results from an equilibrium calculation differ significantly from those of DYN since the fraction of finemode nitrate to total nitrate (gas plus aerosol) is 9.8%, compared to 13% in DYN. Our results suggest that the estimates of aerosol forcing from equilibrium concentrations will be underestimated. We also show that two common approaches used to treat nitrate and ammonium in aerosol in global models, including the first-order gas-to-particle approximation based on uptake coefficients (UPTAKE) and a hybrid method that combines the former with an equilibrium model (HYB), significantly overpredict the nitrate uptake by aerosols especially that by coarse particles, resulting in total nitrate 2 aerosol burdens higher than that in DYN by +106% and +47%, respectively. Thus, nitrate aerosol in the coarse mode calculated by HYB is 0.18 Tg N, a factor of 2 more than that in DYN (0.086 Tg N). Excessive formation of the coarse-mode nitrate in HYB leads to near surface nitrate concentrations in the fine mode lower than that in DYN by up to 50% over continents. In addition, near-surface HNO 3 and NO x concentrations are underpredicted by HYB by up to 90% and 5%, respectively. UPTAKE overpredicts the NO x burden by 56% and near-surface NO x concentrations by a factor of 2-5. These results suggest the importance of using the more accurate hybrid dynamical method in the estimates of both aerosol forcing and tropospheric ozone chemistry.3

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IMPACT, the LLNL 3‐D global atmospheric chemical transport model for the combined troposphere and stratosphere: Model description and analysis of ozone and other trace gases

Cited by 115 publications

References 145 publications

Errors and improvements in the use of archived meteorological data for chemical transport modeling: an analysis using GEOS-Chem v11-01 driven by GEOS-5 meteorology

Errors and improvements in the use of archived meteorological data for chemical transport modeling: an analysis using GEOS-Chem v11-01 driven by GEOS-5 meteorology

Role of dust alkalinity in acid mobilization of iron

Heterogeneous Chemistry: Understanding Aerosol/Oxidant Interactions

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