Argo Profiling Floats

Argo floats are another revolutionary change in in-situ ocean observing in the Indian Ocean. The build-up began in 2003 as part of the global description of the variability of the upper ocean thermohaline structure and circulation on seasonal and inter-annual time scales. Data from these floats, together with the satellite based-and other in-situ observations, would enhance the understanding of the ocean circulation pattern and its influence on the global climate variability and would contribute to improve prediction skills of seasonal climate variability. The Indian Ocean (north of 40°S) requires 450 floats to meet the Argo design of one float per 3° x 3° grid. Around 441 floats are active as on October 31, 2009. Still there are some gaps and other places where more than required floats are present. The Argo program's unprecedented spatial and temporal coverage of density and geostrophic current is opening new perspectives on circulation-research. The new observations combined with a hierarchy of models are likely to address many unanswered questions.

Argo observations in the Indian Ocean are creating many new insights by many different authors studying many aspects of the Indian Ocean. Thus Argo enables a new understanding of the upper ocean variability of Arabian sea, such as summer cooling during contrasting monsoons, temporal variability of the core-depth of Arabian Sea High Salinity Water mass (ASHSW), buoyancy flux variations and their role in air sea interaction, identification of the low-salinity plume off the Gulf of Khambhat, India, during post-monsoon period, mixed layer variability of western Arabian Sea, seasonal variability of the observed barrier layer, the importance of upper ocean temperature and salinity during cyclones, to reveal a pronounced westward propagation of subsurface warming in the southern tropical Indian Ocean associated with Rossby waves on the sloping thermocline, intense cooling of the sea surface at intraseasonal time scales in the southern tropical Indian Ocean during austral summer, etc. Also these data are used to study the the impact of assimilation in simulating temperature and salinity in the Indian Ocean (Masumoto et al. 2009 and references therein).

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