Center for Astroparticle Physics and Space Science (CAPSS)

Space Science

The understanding of changes in climate and weather conditions, especially the significant changes which has occurred in past decade, necessitates a good knowledge of all the factors contributing to the global radiation budget, aerosols and clouds being the most important ones. Aerosols, small particles suspended in air, may occur naturally, originating from volcanoes, dust storms, forest and grassland fires, living vegetation, and sea spray. Human activities, such as the burning of fossil fuels also generate aerosols. Aerosols, natural and anthropogenic, have a large impact on the radiative balance of the Earth and subsequently on climatic change through the scattering of incoming sunlight, cloud formation, or enhanced absorption of sunlight by soot. On the other hand, clouds also play a major role in climate through their direct interactions with solar radiation and also through a variety of indirect effects, for example cloud lifetime, precipitation and energy redistribution. Clouds absorb the infrared radiation emitted by the earth. So they play an important role in the radiative balance of the earth and also influence the speed of the photochemical reactions.

The aerosol-cloud interaction becomes more complex due to role played by cosmic ray. Cosmic Rays are main source of ionization in the atmosphere, apart from the radioactive sources in the earth’s crust which are dominating source of ionization near the earth’s surface. There has been suggestion of a possible forcing mechanism through the effect of galactic cosmic rays on the weather, involving cloud processes such as condensation nucleus abundances, thunderstorm electrification and thermodynamics, or ice formation in cyclones. On the other hand, cosmic rays are also the carrier of solar variablility to the lower atmosphere. There is a change in the flucx of cosmic ray due to solar phenomena, such as, Forbush decrease which is a sudden decrease in cosmic ray in intensity followed by gradual recovery during several days, even weeks. This is thought to occur as the interplanetary shocks passing through earth’s orbit produce an effective barrier. This shock occurs following solar coronal mass ejection.

To understand these complex phenomena, one needs to understand both physical and chemical aspects of the atmosphere along with the observational aspects. At Bose Institute we are involved in the following aspects of atmospheric science:

Group Members:

Faculty / Scientist Student / RA
Sibaji Raha
Sanjay K. Ghosh
Amitabha Mitra
Partha Sarathi Joardar
Soumendra Singh

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