Variations in aerosol optical and microphysical properties during an Indian festival observed with space-borne and ground-based observations

K. VIJAYAKUMAR, P. C. S. DEVARA

Abstract

This study analyzes changes in the response of meteorological parameters, aerosol, ozone, and water vapor properties over a tropical urban station in Pune, India, using ground-based and satellite data sets from February 23 to March 4, 2010 covering the Holi festival period. Continuous ground-based measurements of Microprocessor-based Total Ozone Portable Spectrometer (Microtops II) were made. The variations in aerosol optical depth (AOD) showed higher values on March 1, 2010 which coincide with the peak festival time. Using the least squares method, Ångström exponent (α) is calculated in the spectral interval of 340-1020 nm, along with the coefficient a2 of the second-order polynomial fit to the plot of log AOD versus the log wavelength. The correlation between the coefficient a2 vs. AOD500 nm is discussed. Results from ground-based Microtops and CIMEL sun-sky radiometer observations are also found to match well with satellite retrievals. The aerosol index (AI) derived from the Ozone Monitoring Instrument (OMI) along with AOD derived from the Moderate-Resolution Imaging Spectrometer (MODIS) indicate positive correlation. This suggests that satellite observations over the region confirm the presence of absorbing aerosols mainly due to bio-mass burning and colored powder spray activities during the festival.

Keywords

Microtops II; Ångström exponent; sun-sky radiometer; aerosol optical depth; Holi; OMI; MODIS

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