MEZCAL: Methods for Extending the horiZontal Coverage of the Amoc Latitudinally and retrospectively

Department Name: Science and Technology


The AMOC is a large-scale ocean circulation system composed of currents that carry warm, shallow water northwards and return cold, deeper water southwards. The AMOC is crucial in maintaining the relatively mild winter climate of Northwest Europe. A shutdown of the AMOC would strongly impact European temperature and precipitation variability.

Because of the AMOC's role in regulating the global climate system, several direct ocean observing programmes have been put in place to monitor the AMOC. In the North Atlantic, the two main observing arrays are the Rapid Climate Change Program (RAPID) and the Overturning in the Subpolar North Atlantic Program (OSNAP) at 26N and 50-60N, respectively. While these programmes have transformed our understanding of changes in the AMOC, they are limited to single lines of latitude and have relatively short lifespans (two decades at most). These constraints prevent us from being able to understand changes on long (decadal to centennial) timescales or understand how the AMOC is connected across the latitudes where we don't have direct measurements. Further, the maintenance of the observing arrays is costly and there is no backup system in place in the event of instrumentation failure or loss.

To overcome the limitations of the RAPID and OSNAP observing arrays, the oceanographic community has sought alternative solutions for monitoring the AMOC using cost-effective observing systems, like existing satellite and autonomous ocean robot data that have high spatial and temporal coverage. These alternative solutions for monitoring the AMOC have recently been trialled at a few places in the North Atlantic. At the same time, advances in machine learning and modelling methods are starting to prove useful for monitoring the AMOC from indirect measurements.

The AMOC monitoring at RAPID and OSNAP will soon achieve 20- and 10- years worth of continuous measurements, respectively. The combination of these AMOC records with the recent developments in alternative AMOC monitoring methods means that the oceanographic community now has the tools in place to dramatically improve our ability to understand the AMOC across the North Atlantic Ocean over long time periods. Thus, MEZCAL will combine computational advances with the recent proven alternative methods for monitoring the AMOC to extend the coverage of AMOC observations across the North Atlantic and deliver a new framework that will make a step change in our understanding of AMOC variability. This project will also provide recommendations for how to build a sustainable AMOC monitoring system moving forward.


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