The evolution of ARFI and ICARB projects presents the saga of nearly 30 years’ of collective national teamwork, which stood the test of time to become benchmarks in atmospheric science endeavours. Entwining the concepts of in-house design and development of scientific instruments; algorithms for operation, data deduction, and scientific analysis; realizing and maintaining a national network through a collective team effort involving national laboratories, academic institutions, and universities spread across the country, and above all contributing to the noble cause of capacity building, these projects showcase the evolution of a modest research theme into a national endeavour with a unique national and international identity.

The early 1980s witnessed a rejuvenation of atmospheric science research in India, with the advent of the Indian Middle Atmosphere Program (IMAP). During this, a 10-channel multi-wavelength solar radiometer (MWR) was designed and developed in-house in SPL and a mini-national network of MWRs was realized in 1987, instigating the concept of a national network with common protocols for instrumentation and data deduction.

Taking a cue from the success of IMAP, ISRO gave shape to its Geosphere-Biosphere Programme (I-GBP) in 1991, to address to specific scientific themes of national and regional significance, besides fundamental research on Geosphere and Biosphere interactions. This evolved into a professional, multi-pronged, approach in the scientific endeavours related to aerosols, clouds and radiation taking the science on par with the frontline work in the international scene. Leading from the front, SPL gave shape to two major national projects, unparalleled in recent history on aerosols, namely the Aerosol Radiative Forcing over India (ARFI) project and Integrated Campaign on Aerosols and Radiation Budget (ICARB).

From the modest, concept-proving network of 1983, ARFI has travelled a long way to a national operational network of 41 observatories spanning the length and breadth of India; from Trivandrum to Hanle, and Nalia to Dibrugarh, and aims at generating a regional aerosol database, radiative forcing maps and climate impact assessment. The ICARB, on the other hand, envisages mega-field experiments, focusing on specific themes that feed to ARFI.

The exciting and very unique discovery, during ICARB, of the elevated atmospheric warming by aerosol absorption and its northward gradient in height and amplitude led to the formulation of a new scientific experiment ‘Regional Aerosol Warming Experiment (RAWEX)’. Significant progress has been made under RAWEX, which includes establishing an observatory at the high altitude station at Hanle (4.5 km amsl) and high altitude balloon experiments, opening up a new question ‘Do BC makes its own home up in the atmosphere?’.