A roadmap to IndOOS-2: Better observations of the rapidly-warming Indian Ocean

Almost one-third of humanity lives around the Indian Ocean, many in countriesdependent on fisheries and rain-fed agriculture that are vulnerable to climate variabilityand extremes. The Indian Ocean alone has absorbed a quarter of the global oceanic heatuptake over the last two decades and the fate of this heat and its impact on future changeis unknown. Climate models project accelerating sea level rise, more frequent extremes inmonsoon rainfall, and decreasing oceanic productivity. The Indian Ocean ObservingSystem (IndOOS), established in 2006, is a multi-national network of sustained oceanicmeasurements that underpin understanding and forecasting of weather and climate forthe Indian Ocean region and beyond. A three-year, international review of the IndOOSby more than 60 scientific experts highlights the need for an enhanced observing networkthat can better meet regional scientific and societal challenges and provide more reliableforecasts. Here we present core findings from this review, including the need for 1)chemical, biological, and ecosystem measurements alongside physical parameters; 2)expansion into the western tropics to improve understanding of the monsoon circulation;3) better resolved upper-ocean processes to improve understanding of air-sea couplingand yield better sub-seasonal to seasonal predictions; and 4) expansion into key coastalregions and the deep ocean to better constrain the basin-wide energy budget. These goalswill require new partnerships with and among Indian Ocean rim countries, creatingopportunities for them to enhance their monitoring and forecasting capacity as part ofIndOOS-2.