Status of ocean observations in the Indian Sector of the Southern Ocean

One of the largest sectors of the Southern Ocean is the Indian Sector, which plays an important role in regulating the Earth’s climate and supports a diverse ecosystem. To understand how climate change impacts the environment in this sector, ocean observations are collected via various platforms, including conventional ship-based technologies, autonomous instruments (e.g., animal-borne sensors, autonomous underwater vehicles, and profiling floats), satellites, and other remote sensing methods. However, the harsh environment, remoteness, and natural obstacles such as sea ice and clouds limit year-round ocean observations by vessel and satellite, respectively. This incomplete data coverage makes predicting future scenarios a challenge. Here, led by the Regional Working Group for the Indian Sector of the Southern Ocean in the Southern Ocean Observing System, we examined the status of multidisciplinary ocean observations in the Indian Sector. Our review covers oceanography, sea ice, biogeochemistry, air–sea flux, pelagic and benthic biology, and direct anthropogenic pressures. We also address seasonal and spatial gaps, along with platform biases. Furthermore, we explore the synergies between modelling and observations, highlighting how models can test hypotheses, address observational gaps, and, in turn, benefit from improved observational data. Finally, we provide recommendations for enhancing the observing system in the Indian Sector of the Southern Ocean to better understand its current state and anticipated future changes.