Dust events in Kanpur, northern India: Chemical evidence for source and implications to radiative forcing

Dust samples were collected and analyzed during May 2004 in Kanpur (in Ganga basin), Northern India for the first time. Chemical evidence along with the air mass trajectories suggests three major sources of the mineral dusts transported to the Ganga basin. High concentration of Pb and Cd indicates possible mixing with the anthropogenic pollution. The composite aerosol model reveals low single scattering albedo (∼0.74) due to the presence of black carbon. During the dust storms, shortwave (SW) clear‐sky diurnally averaged top of the atmosphere (TOA) and surface forcing come out to be +11 ± 0.7 and −26 ± 3 W m−2, respectively. Corresponding forcings in the longwave (LW) region are +1.9 ± 0.6 and +1.6 ± 0.4 W m−2. Net atmospheric forcing (i.e., SW+LW, 36 W m−2) corresponds to heating rate of ∼1.02° K/day in the lower atmosphere. Dust alone has resulted in the net TOA and surface forcings of +7 and −12 W m−2.

[1]  B. N. Holben,et al.  Retrieval of black carbon and specific absorption over Kanpur city, northern India during 2001-2003 using AERONET data , 2006 .

[2]  R. B. Singh,et al.  Aerosols over Delhi during pre‐monsoon months: Characteristics and effects on surface radiation forcing , 2005 .

[3]  J. Srinivasan,et al.  Regional distribution of absorbing efficiency of dust aerosols over India and adjacent continents inferred using satellite remote sensing , 2005 .

[4]  Brent N. Holben,et al.  Seasonal variability of the aerosol parameters over Kanpur, an urban site in Indo-Gangetic basin , 2005 .

[5]  Brent N. Holben,et al.  Influence of dust storms on the aerosol optical properties over the Indo‐Gangetic basin , 2004 .

[6]  J. Perlwitz,et al.  Surface radiative forcing by soil dust aerosols and the hydrologic cycle , 2004 .

[7]  Anju D K Banerjee.  Heavy metal levels and solid phase speciation in street dusts of Delhi, India. , 2003, Environmental pollution.

[8]  O. Torres,et al.  ENVIRONMENTAL CHARACTERIZATION OF GLOBAL SOURCES OF ATMOSPHERIC SOIL DUST IDENTIFIED WITH THE NIMBUS 7 TOTAL OZONE MAPPING SPECTROMETER (TOMS) ABSORBING AEROSOL PRODUCT , 2002 .

[9]  J. Seinfeld,et al.  Radiative forcing by mineral dust aerosols : sensitivity to key variables , 1998 .

[10]  Catherine Gautier,et al.  SBDART: A Research and Teaching Software Tool for Plane-Parallel Radiative Transfer in the Earth's Atmosphere. , 1998 .

[11]  Patrick Pease,et al.  Aerosols over the Arabian Sea: geochemistry and source areas for aeolian desert dust , 1998 .

[12]  P. Koepke,et al.  Optical Properties of Aerosols and Clouds: The Software Package OPAC , 1998 .

[13]  Nick Middleton,et al.  A geography of dust storms in South‐West Asia , 1986 .