About

The AMT4CO2flux project is working to develop a processing chain for satellite products and uncertainties for the air-sea flux of carbon dioxide and ocean acidification parameters. This will provide monthly measurements of these parameters which will then be used in estimating global carbon budgets.

This programme builds upon the work of the AMT4OceanSatFlux programme which measured the flux of carbon dioxide between the atmosphere and the ocean; and the AMT4SentinelFRM programme which made fiducial reference measurements at sea to calibrate and ensure the quality of data from the Sentinel satellites. This work enables us to use the data from the satellites with greater confidence. With it we can address large scale issues and scientific questions on the effects of climate change in the global ocean, focusing on those that have a direct bearing on societal issues that humankind will face in the coming decades.

Why measure CO₂ flux

Accurate measurements of CO₂ flux are essential for a better understanding of how anthropogenic emissions of the greenhouse gas CO₂ influence climate and the ocean’s role in the system. To date the oceans have absorbed around 40% of past emissions of CO₂, this has a buffering effect on the atmospheric concentration of the gas, but is also changing the chemistry of the ocean.

The addition of eddy co-variance data to the range of high quality measurements on board the AMT cruise provides verification of state-of-the-art methods for estimating gas exchange. Combining multi-sensor data allows the calculation of global ocean-atmosphere CO₂ fluxes, which is central to our understanding of how the oceans regulate increasing levels of CO₂ and the extent to which this leads to ocean acidification. This large-scale analysis of satellite CO₂ air-sea flux estimates has never been achieved before in the Atlantic Ocean.

left: eddy covariance set-up, centre: radiometers, right: optics rig being deployed

What is ocean acidification?

The absorption of CO₂ is causing a gradual decrease in the pH of the oceans, a phenomenon called ocean acidification. This is having an adverse effect on many important marine species such as corals, oysters, crabs and plankton, and due to the unparalleled rate of acidification the organisms may not have time to evolve mechanisms to cope with the changing ocean chemistry.

What is the Atlantic Meridional Transect?

The Atlantic Meridional Transect (AMT) is a multidisciplinary programme which undertakes biological, chemical and physical oceanographic research during an annual voyage between the UK and destinations in the South Atlantic, a distance of up to 13,500km. The transect crosses a wide range of ecosystems from sub-polar to tropical and from euphotic shelf seas and upwelling systems to oligotrophic mid-ocean gyres making it an ideal platform for monitoring the health of our seas. The programme began in 1995 and provides a unique record of conditions in the Atlantic Ocean.