M.P. Raju

Vertical profiles of black carbon aerosols over the urban locations in South India

Vertical profiles of black carbon (BC) aerosol were determined from aircraft measurements under the Cloud Aerosol Interaction and Precipitation Enhancement Experiment (CAIPEEX) program conducted by the Indian Institute of Tropical Meteorology, India during 2009 over Bangalore and Hyderabad in south India. BC mass loadings decreased approximately monotonically from 10(3) to 10(4) ng/m(3) at the surface to ~10(2) ng/m(3) at an altitude of about 7 km; although layers at intermediate levels containing anomalously high BC loadings were frequently encountered that were attributed mainly to the convective transport from surface sources accompanied by changes in the local boundary layer and atmospheric stability. In addition, as evidenced from air mass back trajectories; long range transport from distant sources contributed to some anomalous spikes in BC concentration. The presence of BC in cloud forming regions of the free troposphere could have important implications for cloud microphysics and subsequent rainfall mechanism over this region. Apart from this, the effects on human health are equally important.

Impact of anthropogenic activity and cyclonic storm on black carbon during winter at a tropical urban city, Pune

AbstractnBlack carbon (BC) aerosols are emitted into the atmosphere as a byproduct of different combustion processes and are reported to be a very strong absorber of solar radiation. In this paper, we present results on BC aerosols over Pune, a tropical urban city in south west India during Diwali festival in the month of November 2010. Daily mean BC showed about 5xa0% increase on Diwali day compared with preceding and succeeding period with concentrations reaching as high as about 21xa0μg/m3 in the morning on Diwali day, mainly due to the influence of extensive fireworks. However, the strong winds accompanied by occasional rainfall due to severe cyclonic storm “Jal” formed in the Bay of Bengal on the same day dampened this effect and reduced BC to about 2xa0μg/m3 within 6xa0h. There was only 5xa0% increase in mean BC concentration on Diwali day during 2010 as compared to the average increase of about 17xa0% during preceding 4xa0years on Diwali day, mainly due to the impact of weather conditions induced by Jal.