A dive into tropical waters: understanding the mechanisms of sea surface temperature patterns that drive global climate and weather

Description

Sea surface temperature patterns in tropical oceans influence climate and weather around the globe. The El Niño Southern Oscillation (ENSO, 1, 2) in the Pacific and its teleconnections drive rainfall patterns nearby and far, as well as influences the occurrence of Marine Heat Waves in remote areas. Analogous to ENSO, the tropical Atlantic displays a pattern of interannually changing sea surface temperatures (SST), the Atlantic Niño (3). The Atlantic Niño influences weather over African, South America and Europe. Both SST patterns display alternating warming and cooling of the eastern equatorial cold tongues. The cold tongues are regions of cold SST in the tropical belts that absorb large amounts of heat into the oceans, providing the ocean circulation with energy (4, 5). These regions of the ocean are therefore crucial regulators of global climate and weather and the het balance of the planet.

ENSO and the Atlantic Niño are driven by coupled air-sea interaction: the ocean triggers a change in the atmosphere which then again triggers a change in the ocean, creating a feedback loop. This feedback includes processes on basin-wide scales on the order of thousands of miles, down to small scale ocean mixing on the order of centimetres.

The overarching goal of the project is to advance our understanding and our ability to simulate tropical Atlantic and Pacific SST variability, which can be achieved in many ways. Possible routes of scientific investigation are:

• Analysis of scale-interactions in the tropical oceans based on existing high resolution ocean model output and historic data.
• Comparison of the processes driving Atlantic and Pacific variability, how do they differ and how are they similar? Can we learn from one ocean basin about the other, and what are the differentiating factors?
• Evaluation of the representation of the small-scale processes involved in this air-sea coupling as they are currently implemented in ocean models, devising strategies to compare to the (sparse) existing data and potentially .

The successful candidate will have the opportunity to choose their desired path or a combination of the above outlined questions. You can investigate the scale-interactions behind these impactful SST patterns in the Atlantic and Pacific ocean, as well as their effect on climate, and how they are represented in climate models. Some of these processes can be explicitly represented in climate models, while others are too small scale and must be approximated by parameterizations to include their effect. The successful candidate will have the opportunity to learn more about parameterizations and help advance our ability to reliably simulate the ocean (the modelling route), but there is also an opportunity to choose a path that requires analysing and possibly generating more model simulations together with available data (the analysis route). These two paths do not have to be mutually exclusive.

As the successful PhD candidate you will have access to a large number of ocean model simulations at various resolutions to be analysed, together with the historic record of observational data. There is an opportunity to accompany the lead PI on oceanographic expeditions to the tropical Pacific and gather observational oceanography experience. This work is to be performed in the framework of a major upcoming field campaign targeting the observation and understanding of equatorial Pacific coupled air-sea processes, TEPEX (6). The successful PhD candidate will have the opportunity to collaborate with the international team of researchers contributing to the campaign, as well as the international collaborators of the lead PI based at, for example, the National Centre for Atmospheric Research (NCAR) in Boulder, Colorado, the National Oceanic and Atmospheric Administration (NOAA), Scripps Institution of Oceanography in San Diego, California and the University of Washington in Seattle, Washington.

For full consideration, please apply before the 31st of January. Applications will continue to be reviewed until a suitable candidate is selected