Aerosols, Clouds, Precipitation, and Hydrological Cycle

Precipitation from clouds is probably the end of the hydrological cycle, and a chief contributor to sustainability of life. Water molecules evaporate from the water bodies on Earth, the soils, and evapo-transpiration from plants, condense to form clouds, and return to earth mainly by precipitation to complete the cycle. While there is an intrinsic space-time distribution for this cycle, any significant changes in the spatial and temporal distribution of rainfall, can have a dramatic effect on climate and society.

Aerosols (suspended particles in the atmosphere) act as cloud condensation nuclei around which water drops are formed; through nucleation and condensation. Hence, changes in the physico-chemcial properties of aerosols are bound to impact cloud properties, precipitation and cloud radiative properties. However, the role of aerosols on cloud properties and precipitation strongly depends on aerosol properties on the one hand (which depends on the sources and microphysics of aerosols) and the cloud properties (cloud drop size distribution, liquid water content, optical depth, altitude etc) which are controlled my atmospheric dynamics and thermodynamics. In addition, the scattering and absorption of solar radiation by aerosols is also a significant pathway to change the ambient atmospheric conditions such as temperature and stability, cloud formation, convection and even large-scale circulation. Though atmospheric water vapour, aerosols, clouds and precipitation are well observed over the globe, scientific studies on the interaction between them are still in the infancy, especially over South Asian region, where complex aerosol system prevails along with highly seasonal synoptic meteorology.

This special session on 'Aerosols, Clouds, Precipitation, and Hydrological Cycle' aims to bring together the scientific fraternity working on the modelling and observational studies on the effects of aerosols on clouds and precipitation, properties and distribution of clouds and precipitation and how various atmospheric processes influences the hydrological cycle.

Last date of submission of abstract: 15 June 2019