Modeling and analysis of aerosol processes in an interactive chemistry general circulation model

Abstract

[1] An ''online'' aerosol dynamics and chemistry module is included in the Laboratoire de Météorologie Dynamique general circulation model (LMDZ), so that the chemical species are advected at each dynamical time step and evolve through chemical and physical processes that have been parameterized consistently with the meteorology. These processes include anthropogenic and biogenic emissions, over 50 gas/aqueous phase chemical reactions, transport due to advection, vertical diffusion and convection, dry deposition and wet scavenging. We have introduced a size-resolved representation of aerosols which undergo various processes such as coagulation, nucleation and dry and wet scavenging. The model considers 16 prognostic tracers: water vapor, liquid water, dimethyl sulfide (DMS), hydrogen sulfide (H 2 S), dimethyl sulphoxide (DMSO), methanesulphonic acid (MSA), sulfur dioxide (SO 2 ), nitrogen oxides (NO X ), carbon monoxide (CO), nitric acid (HNO 3 ), ozone (O 3 ), hydrogen peroxide (H 2 O 2 ), sulfate mass and number for Aitken and accumulation modes. The scheme accounts for two-way interactions between tropospheric chemistry and aerosols. The oxidants and chemical species fields that represent the sulfate aerosol formation are evolved interactively with the model dynamics. A detailed description on the coupled climate-chemistry interactive module is presented with the evaluation of chemical species in winter and summer seasons. Aqueous phase reactions in cloud accounted for 71% of sulfate production rate, while only 45% of the sulfate burden in the troposphere is derived from in-cloud oxidation.Citation: Verma, S., O. Boucher, M. S. Reddy, H. C. Upadhyaya, P. Le Van, F. S. Binkowski, and O. P. Sharma (2007), Modeling and analysis of aerosol processes in an interactive chemistry general circulation model,

Variations in sulphate aerosols concentration during winter monsoon season for two consecutive years using a general circulation model

“…1) however, the magnitudes of these plumes can be underestimated at a point location, as is also evident from earlier studies using the model version described here (Verma et al, 2006(Verma et al, , 2007(Verma et al, , 2012. The results (Fig.…”

“…The LMDZ model has the capability of reproducing the spatial distribution of aerosols over Asia and capturing the major features of AOD spatial distribution, as is evident from Verma et al, 2006Verma et al, , 2007 ) has been evident in EXP01 and EXP02 simulations. The average sulphate concentration has been enhanced over Indian continents with a value of 1.5-3 to 3-6 µg m -3 (Fig.…”

“…The shortwave radiative processes within the LMDZT are accounted by dividing the shortwave spectrum into two intervals of 0.25-0.68 µm and 0.68-4 µm wavebands. More description on the model can be found in Verma et al (2007).…”

“…The present simulations of sulphate aerosol distribution were carried out with the general circulation model LMDZT with interactive sulphur chemistry of the Laboratoire de Météorologie Dynamique (Verma et al, 2007). The sulphur chemistry is calculated directly within the LMDZT and allows for the complex interaction between chemistry and climate to consider the role of sulphate aerosols on the climate system, in comparison to other chemical transport models (CTMs) which employ analyzed meteorology or observations to derive the CTM.…”

“…The connection between the winter circulation pattern and the dynamics of formation of sulphate aerosols concentration is also illustrated, which can improve understanding on the role of sulphate aerosols on global climate. For this purpose an interactive chemistry module developed at IIT Delhi combined with LMDZ (a variable grid GCM of Dynamic Meterological Lab, Paris) is used to simulate sulphur chemistry during INDOEX (Verma et al, 2007).…”