Hi MOOCer’s I’m a 2nd year PhD student researching the controls on the Southern Ocean overturning circulation. As a kid my favourite part of the year was visiting the mountains; from our own Welsh and Scottish hills to the slightly more formidable Alps. I had no idea what I wanted to go and do after school, but I knew I didn’t want to be stuck in a lab all day so Earth Sciences which had abundant field trips to mountains seemed like a logical choice. When I was leaving school I was lucky enough to gain a place on a British Exploring Society trip to Greenland where I spent time travelling round amazing fjords (looking pretty cold!) and glaciers. Here we took some photos to compare the glacial extent from 20 years ago, it was shocking to see how much the glacier had receded in so little time!
I did a 4 year undergraduate masters degree in Earth Sciences and as promised there were lots of field trips, however the geology could not compare to what I’d seen in Greenland and I grew increasingly interested in the physics of the climate system. Learning about large scale ocean processes and their place in the climate system soon set me on the path to oceanography. Not only was it fascinating to see quite complex processes broken down into simple approximations balancing the winds and the planets rotation, but also the effects the ocean have on our climate and weather.
I hadn’t heard of oceanography before I went to university, but in my 3rd year when we had to pick an extended essay and a lecturer suggested one on “The Role of Eddies in the Southern Ocean” which sold me of the idea of perusing ocean sciences. Oceanography also came with a field trip in my master’s year to Bermuda!
Apart from the trip to Bermuda I haven’t actually ended spending much time at sea. I went down the route of physical oceanography where there are two main camps: observationalists and modellers. There’s a big drive to get the two more interconnected, but you do tend to end up as one or the other! In my master’s year I got introduced to high resolution state of the art ocean models. In a nutshell you break the ocean down into 1000s of tiny boxes and get a supercomputer to solve a set of fundamental equations to capture the ocean’s behaviour. For my masters project I used MITgcm (MIT General Circulation Model) data to investigate transports of heat and salt by small scale features (less than 100km across, we actually call them mesoscale as you can actually go much smaller scale in the ocean!) called eddies (like ocean storms). Ocean eddies are quite complex features that vary significantly in time and space that can effect large scale processes; modelling them is difficult because it costs a lot to run models at a high enough resolution to capture what they’re doing!
I loved the challenge of working with such a large dataset, there was endless possibilities of interesting features you could investigate. I really enjoyed working on eddy mechanisms and how they fit in to the larger scale processes. These small transient features can that affect the global overturning circulation, which in turn can have massive impacts on our climate system. I didn’t really want to stop, so I started looking into doing a Ph.D and found there’s a lot of interesting research going on out there! I enjoy being able to discuss ideas with people and share information and experience so coming to the National Oceanography Centre with the University of Southampton was a great opportunity I couldn’t turn down.
I’ve now been doing my Ph.D research for a year and it’s been great! I now use the same model from my masters to set up my own experiments running on the local supercomputer here. I use a simple idealised channel model to represent the Southern Ocean. I’m trying to capture the essential physics behind what’s setting the circulation. This is important because of how interconnected the oceans are; changing the Southern Ocean circulation can have large effects on the global overturning circulation. A diagram of my model. Don’t worry too much about the physics! I’ve just set up a box and blown a wind over it to create a flow that represents the Antarctic Circumpolar Current and heated and cooled the surface in a similar way to current observational estimates to see what happens to the circulation!