Seasonal and inter-annual variability of tropospheric aerosol and trace gases over India: observation and modeling study

Rapid economic development in the last few decades throughout much of India led to dramatic increase in anthropogenic emissions of trace gases (both short-lived and long-lived) and aerosols. Aerosols originating from biomass burning, vehicular and industrial emission, long-range transport of dust in Indian subcontinent are recognized as the major source of pollution. Multiple satellite observations are used to examine mean and variability of aerosol optical depth (AOD) and mixing ratios of pollutant like CO, O3 and NO. Multi-year analysis of different aerosol species (BC, Dust, Sulfate) simulated by GOCART aerosol transport model are used to study local and regional source and sinks of each individual species in temporal scale and possible interrelation between them. In the northern part of the country, Dust aerosols dominate between April-July, Sulfate during monsoon months (JJAS) and BC during winter season (DJF). Meteorological variables from NCEP Climate Forecast System Reanalysis (CFSR) are used to understand control of meteorology on the spatial and temporal variability of these species over the region. Finally, relative performance (based on annual and seasonal scale and variability) of a subset of models participating in the 5th Coupled Model Intercomparison Project (CMIP5) are assessed against observations.