HR: 15:28h
AN: A23D-09 [Abstracts]
TI: Black Carbon Absorption Over Kanpur (an Industrial City in the Indo-Gangetic Basin) Retrieved From
AERONET Data
AU: * Tripathi, S N
EM: snt@iitk.ac.in
AF: Assistant Professor,Department of Civil Engineering, Indian Institute of Technology, Kanpur, Department
of Civil Engineering, Indian Institute of Technology, Kanpur, Kanpur, UP 208016
India
AU: Dey, S
EM: sagnik@iitk.ac.in
AF: Assistant Professor,Department of Civil Engineering, Indian Institute of Technology, Kanpur, Department
of Civil Engineering, Indian Institute of Technology, Kanpur, Kanpur, UP 208016
India
AU: Singh, R P
EM: rsingh3@gmu.edu
AF: Assistant Professor,Department of Civil Engineering, Indian Institute of Technology, Kanpur, Department
of Civil Engineering, Indian Institute of Technology, Kanpur, Kanpur, UP 208016
India
AU: Singh, R P
EM: rsingh3@gmu.edu
AF: School of Computational Sciences, George Mason University, School of Computational Sciences, George
Mason University, Fairfax, Virginia 22030, USA, Fairfax, VRG 22030
United States
AB:
Black carbon (BC) is the main anthropogenic absorbing particles in the atmosphere causing large positive radiative forcing.
In India, BC concentration is being monitored by aethalometer at few locations, mostly in campaign modes. However, the
Indo-Gangetic basin in northern India, one of the most populated basins in the world is devoid of any such direct
measurements. An automatic sun/sky radiometer has been deployed in Kanpur, an industrial city in the heart of the
Indo-Gangetic basin, in collaboration with NASA under Aerosol Robotic Network (AERONET) to monitor aerosol parameters since
January 2001. In this paper, we have retrieved column-integrated BC concentration and specific absorption cross section
($\alpha$_{a}$) due to BC using Maxwell Garnett dielectric functions assuming internal mixing of BC with other aerosols.
Values of refractive indices (real and imaginary parts) retrieved by AERONET have been used in BC volume fraction
calculations. We have considered spherical retrieval for winter (December-February) and post-monsoon (September-November)
seasons, spheroid retrieval for pre-monsoon (April-May) and monsoon (June-August) seasons and combined spherical and spheroid
retrievals for March and September during the transition months based on the aerosol optical properties.
BC concentration over Kanpur is found to be higher during the winter and post-monsoon seasons compared to that during the
pre-monsoon and monsoon seasons. Yearly averaged column-integrated BC concentrations over Kanpur are found to be 8.185, 5.564
and 7.723 mg/m2, whereas the corresponding values of $\alpha$_{a}$ are found to be 9.562, 11.976 and 10.07 m2/g at 0.44
$\mu$m wavelength for 2001, 2002 and 2003 respectively. $\alpha$_{a}$ is found to be higher during the pre-monsoon season due
to the preponderance of coarser dust particles. During the post-monsoon to winter seasons, anthropogenic pollutants are
transported over the region by northwesterly winds. Spectral signature of single scattering albedo also supports the idea
that the post-monsoon and winter seasons are characterized by relatively higher concentrations of absorbing particles. In
this paper, the inter-annual, seasonal and diurnal variations of BC concentrations over Kanpur will be discussed in view of
their effect on the regional climatology.
DE: 3309 Climatology (1620)
DE: 1610 Atmosphere (0315, 0325)
DE: 0305 Aerosols and particles (0345, 4801)
SC: Atmospheric Sciences [A]
MN: 2004 AGU Fall Meeting