Filter-based Correction Algorithm for Aerosol Optical Properties in Support of the COALESCE network

SLP Topic for the IITB-WUStl Joint Masters program

Collaborator: Prof. Rajan Chakrabarty (WUStL)


This project is focused on developing robust process-based correction schemes for accurately determining aerosol optical properties using filter-based measurement techniques and bounding the associated errors. Wavelength-dependent correction factors, based on first principles, will be established for aerosol emitted in urban and biomass burning environments. New filter-aerosol correction schemes and process-based understanding resulting from this study will be applied to absorbance datastreams collected during the COALESCE [1] project, a multi-institution network led by IIT Bombay. The proposed work is expected to enable more faithful representation of aerosol optical properties from India in regional climate models and emission inventories.

Aerosol light absorption and scattering of solar radiation play an important role in the earth’s atmosphere in terms of direct and semi-direct radiative forcing.  Optical parameters of importance to the radiative transfer modules in climate models include absorption and scattering coefficients, single scattering albedo (SSA), absorption Angstrom exponents (AAE), and the asymmetry parameter (g). These parameters depend on aerosol size, shape and composition (refractive index), and are spectrally sensitive in the shortwave region. Additionally, these parameters have a complex dependency on the emission source, especially for carbonaceous aerosols. 

The development and application of improved correction algorithms for processing of ambient raw filter measurement datasets and value-added products (VAPs) such as SSA, AAE, and g (singe scatter albedo, absorption angstrom exponent and asymmetry parameter) is essential to enable use of processed data products by the community toward developing, evaluating, and ultimately improving the parameterization of aerosol-radiation processes in climate models. 

Note: A Master’s student working on this project can expect technical help provided by graduate students and postdocs at Washington University in St. Louis.

Evaluation: Regular progress presentations during the semester to advisors; report and presentation to an examining committee at the end of the semester.



1. Venkataraman, C., M. Bhushan, S. Dey, D. Ganguly, T. Gupta, G. Habib, A. Kesarkar, H. Phuleria, R. Sunder Raman (2020) Indian network project on Carbonaceous Aerosol Emissions, Source Apportionment and Climate Impacts (COALESCE), Bull. Am. Met. Soc.,

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