The Indian Ocean Tropical Gyre and associated heat-salt Transport and its ecological impact: A review

With the developing observation system, our understanding of Indian Ocean circulation has advanced in recent years. We have noticed the rapid increase of the ocean content in the Indian Ocean, and its role in global climate changes. In the mean state, a relatively closed current loop is established by an eastward current along the equator and a westward current south of the equator, regarded as the Indian Ocean Tropical Gyre (IOTG). As an important component of Indian Ocean air-sea interaction, the essential impacts of IOTG have been discovered. Due to the monsoon, IOTG displays significant seasonal variations, characterized by the reversal of currents and associated heat-salt redistribution. Also, IOTG interacts with the climate modes. This paper summarizes the advances, including the multi-scale variations of IOTG, associated heat-salt transport, and its ecological impact.