https://doi.org/10.5194/acp-2019-731 Preprint. Discussion started: 26 November 2019 c Author(s) 2019. CC BY 4.0 License. Manuscript for Atmos. Chem. Phys. 1 2 3 4 5 6 7 8 9 10 Space-time variability of ambient PM2.5 diurnal pattern over India 11 from 18-years (2000-2017) of MERRA-2 reanalysis data 12 13 14 15 16 1Kunal Bali*, 1,2Sagnik Dey, 1Dilip Ganguly and 3, 4Kirk R. Smith 17 1Centre for Atmospheric Sciences, Indian Institute of Technology Delhi, Hauz Khas, 18 New Delhi, India 19 20 2Centre of Excellence for Research on Clean Air, Indian Institute of Technology 21 Delhi, Hauz Khas, New Delhi, India 22 23 3School of Public Health, University of California, Berkeley, USA 24 25 4Collaborative Clean Air Policy Center, New Delhi, India 26 27 28 29 *Corresponding author:
[email protected] 30 31 32 33 34 35 36 37 38 1 https://doi.org/10.5194/acp-2019-731 Preprint. Discussion started: 26 November 2019 c Author(s) 2019. CC BY 4.0 License. Manuscript for Atmos. Chem. Phys. 39 Abstract 40 Estimating ambient PM2.5 (fine particulate matter) concentrations in India over many 41 years is challenging because spatial coverage of ground-based monitoring, while 42 better recently, is still inadequate and satellite-based assessment lacks temporal 43 continuity. Here we analyze MERRA-2 reanalysis aerosol products to estimate PM2.5 44 at hourly scale to fill the space-time sampling gap. MERRA-2 PM2.5 are calibrated 45 and validated (r = 0.94, slope of the regression = 0.99) against coincident in-situ 46 measurements.