SO-CHIC: Southern Ocean Carbon and Heat Impact on Climate

The topic I will be discussing is how the southern ocean influences climate change and how the SO-CHIC (southern ocean carbon and heat impact on climate change) project aims to understand and quantify the variability of heat and carbon dioxide in the southern ocean.

The oceans of the world play a crucial role in regulating the earth’s climate. Oceans absorb the majority of radiation from the sun and distribute this heat around the globe. When ocean water is heated it evaporates and it affects the humidity of the surrounding air to form rain and cause storms and so the ocean affects climate and weather. The southern ocean is disproportionately responsible for absorbing 75% the excess heat and 60% carbon dioxide associated with anthropogenic climate change. However due to the low human population and hostile environment of the southern ocean the way in which heat and carbon dioxide is exchanged between the atmosphere ocean and ice has not been as much as the other oceans.

SO-CHIC is a 5 year long (2019-2024) EU funded project which will investigate this atmosphere-ocean-ice exchange by looking at the key processes controlling this exchange using a combination of observational and modelling approaches. One of these approaches is using a technological instrument called the Air-Sea Interaction Profiler (ASIP) developed in Ireland by Professor Brian Ward of NUI Galway. ASIP is used to observe what is happening in the upper 100 m of the ocean in very fine and temporal detail which fills in the crucial gaps that the longer term instruments provide. It is an autonomous instrument and it runs pre-programmed without any human intervention. ASIP has three thrusters which allow it to submerge into the ocean and then ascend with its own buoyancy. There are sensors mounted on the top of it which provide data on turbulence, temperature and conductivity. When it reaches the surface it connects to a GPS satellite to determine its position and to transmit a message using the Iridium global satellite constellation. After sitting on the ocean surface for 20 minutes it repeated the profile. ASIP is limited by its lithium-ion batteries which provide 7000 m of profiling and need to be replaced once they are used up.