The surface measurements of aerosols and trace gases, "Land Campaign on Aerosols" was complemented by balloon-borne radiosonde and Ozonesonde measurements made up to an altitude of 33 km over Hyderabad. It provided temperature, humidity and Ozone profiles to understand the horizontal and vertical movements. An aerial surveillance was also performed to sample the ambient Carbon Monoxide, Nitrogen Oxides, and Black Carbon in a 100 km north-south corridor over Hyderabad at 4 altitude levels covering 300 meters, 800 meters, 1200 meters and 2000 meters. A Mobile Pulse Lidar (MPL) was also flown both during day and night using an NRSA aircraft covering 6 and 8 km altitudes. The MPL helps in studying the physical properties of atmospheric aerosols in a continuous pulse mode by the green laser of 568 nanometer wavelength.

NRSA aircraft used for aerosol sampling

The deployment of instuments for sampling airborne aerosols and trace gas measurements, as well as these observations over the Indian continent heralds a new chapter in aerosol research and climate observations initiated by ISRO.

The land based aerosol campaign of ISRO-GBP has been carried out for the first time on such
a magnitude in a collaborative manner to characterise the atmospheric aerosols and trace gases. It is also planned to cover the north, northwestern and northeastern parts of India later. With these campaigns, it is possible to provide aerosol optical depth map of India substantially characterised by their chemical constituents, optical properties and trace gas distribution. This study would also provide better insights on the natural and man made sources of aerosols and trace gases and their transport mechanism to distant places. It will be used in the Aerosol Radiation Budget Studies as well as to understand chemical transport mechanism. It will serve as a valuable input to further enhance
our understanding of the different aspects of aerosals and their role in climate studies.

(This article was contributed by Prof Shyam Lal of PRL, Dr C B S Dutt and Dr V Jayaraman of ISRO GBP Programme Office)