Observations show that oceanic flows, temperature and salinity vary on space-time scales of centimetres and seconds to planetary and decadal scales. Debasis Sengupta studies physical processes in the ocean, planetary waves and coherent modes of variability in the ocean and atmosphere. He has worked with students and collaborators on several field campaigns using research ships, deep sea moorings and robotic instruments. The high-resolution observations reveal many new facets of oceanic flows, such as 5 km-wide jets and eddies, sharp changes of ocean salinity, and swift surface currents driven by monsoon winds. The oceanic pathways of river water, and the influence of river water on weather and climate is an abiding interest: Freshwater entering the Bay of Bengal from the great monsoonal rivers of south Asia does not readily mix with saltier ocean water – the low-salinity signature of river water can be traced across the Indian Ocean to the shores of east Africa and Madagascar. In the Bay of Bengal itself, river water inhibits turbulent mixing and storm-induced cooling of sea surface temperature, favouring rapid intensification of post-monsoon tropical cyclones.
Prof. Sengupta studied physics at IIT Delhi and oceanography at NIO Goa. He joined the Centre for Atmospheric and Oceanic Sciences (CAOS), IISc. Bangalore in 1992. His research is supported by DST and MoES.