A063-0003
Analysis of Aerosol Life Cycles over Indian Region in the ECHAM6-HAM2

Wednesday, 9 December 2020
Poster
Anwesa Bhattacharya, Indian Institute of Technology Bombay, Mumbai, India, Chandra Venkataraman, Indian Institute of Technology Bombay, Chemical Engineering, Mumbai, India, Suman Maity, Sun Yat-sen University, Zhuhai, China and Kaushik Muduchuru, Indian Institute of Technology Bombay, Climate Studies, Mumbai, India
Abstract:
In this study, life cycles of natural and anthropogenic aerosols are analyzed in simulations using the ECHAM6-HAM2 GCM. Simulations are made for 2005-2014, with evolving aerosol emissions from SMoG-India (Pandey et al., 2014; Sadavarte and Venkataraman 2014) for the Indian domain, nested in the global CEDS emissions dataset and with nudging of meteorological variables including divergence, vorticity, temperature and pressure. The SMoG-India emission database includes black carbon (BC), organic carbon (OC), sulfur dioxide (SO2), oxides of nitrogen (NOx), ammonia (NH3), anthropogenic mineral matter (MM). Model simulations consider dust (DU), sea salt (SS), sulfate (SO4), BC and particulate organic matter (POM). Aerosol lifecycle processes considered include emissions inputs of anthropogenic and online parameterizations for natural aerosols, aerosol microphysics, sulfate chemistry, wet and dry deposition and water uptake.

In ECHAM the primary dust emission is dependent on a threshold wind friction velocity. This threshold velocity is a function of a parameter which acts as the regional tuning parameter of dust emission (Tegen et al., 2002). The default tuning parameters, which resulted in low dust emission over India, was resolved by adding a separate tuning parameter for the Indian region, raising the dust emissions to 23.11Tg/yr.

The burden and the residence time of DU, BC, POM and SO4 simulated by ECHAM are nearly equal to the AeroCom multi-model mean (Textor et al., 2006), however SS is an exception. The burden of SS is half of the AeroCom mean. The residence time of SS is more than a day for ECHAM whereas, the multi-model mean of SS found by Textor et al. (2006) is only half a day. That implies that the removal processes are slower in ECHAM compared to other models. This could be due to the smaller particle size of SS simulated by ECHAM.



References

Pandey, A., et al., Atmospheric environment 99 (2014): 341-352.

Sadavarte and Venkataraman., Atmospheric environment 99 (2014): 353-364.

Tegen, I., et al., J. Geophys. Res., 107( D21), 4576, 2002.

Textor, C., et al., Atmospheric Chemistry and Physics 6 (2006): 1777-1813.

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