Meet Dr Adele Morrison: close encounters with the Southern Ocean

Exploring the Southern Ocean has been the focus of Dr Adele Morrison’s scientific career. Since her PhD, she has been looking at the physical processes that drive the ocean circulation, trying to understand the impact of these movements on the global climate and sea level.

“I started doing physics as an undergraduate, but when I finished I was not quite ready to go into research. After some time teaching high school maths and physics, I returned to academia. I found climate science was the right place for me: a nice combination of physics with a tangible application to the world’s problems. It is also much easier to explain to your mother what you do and why than the abstract concepts of pure physics.”

Dr Morrison has tackled some of the many mysteries of the effects of climate change on ocean circulation in the Antarctic region.

“We don’t understand yet why the ocean is warming and causing Antarctica to melt. We need to know that to be able to predict how the planet is going to change in the future and, in a more local context, the impact for Australia where 85 per cent of our population live in areas that may be affected by rising sea levels during the next century”.

To do this, Dr Morrison and her colleagues use high resolution ocean and climate models, which are one of the main tools for climate scientists, just like telescopes are for astronomers.

“I have used the ACCESS Ocean Model (ACCESS-OM2) for many years now and have been involved with developing the model configurations, mostly in the validation stage, when we compare the simulations to observations and decide if we need to make changes in the models to be closer to reality.

“Climate models work by dividing the ocean up into little grid boxes. We then work out how water mass moves out and in each tiny box based on things like mass, temperature, heat and salinity. Once you add up all those boxes together, we use physical laws that describe how much stuff moves from one box to another box.”

When you do that over the whole world and have enough resolution, you end up with a perspective of the ocean circulation that looks amazingly real, even with few observations.

A day in an ocean modeller’s life

You might think someone who spends her days wondering how oceans work would live on a boat or at least by the beach, but the reality is quite different.

Dr Morrison lives hours from the beach and spends her days in front of a computer, analysing the data produced by ocean models.

“Our models run on supercomputers, like Gadi at the National Computational Infrastructure. This supercomputer runs the models sometimes for many weeks, producing massive quantities of data that we then analyse. I spend most of my time making sense of all this data in front of my computer.”

It is however, not a lonely enterprise. “Many of our science projects these days are very collaborative. In each of these projects, we have fortnightly hackathons, where we meet online for a couple of hours with 5-10 of us from around Australia. We code and discuss results together and it’s very interactive and collaborative. It’s so much more fun than working on a problem on your own and we learn a lot from each other.”

Dr Morrison notes that being part of the ACCESS community also gives researchers access to many resources.

“In the past, scientists spent a lot of time developing new model configurations. Now, with the new ACCESS National Research Infrastructure, we will have code and documentation available to speed up this task. It is really amazing having research software engineers to support model development – firstly because they are way better at it than most scientists, and secondly because it frees up more of our time to focus on answering scientific questions.”

Collaboration is key

According to Dr Morrison, collaboration is essential for her work, because different researchers bring different expertise and talents to the project.

“In contrast with other areas of science like physics, where often groups are targeting the same question and competing to publish their results first, in climate science the scope of what we have to do is so enormous that there are not enough people to answer all the questions.”

“We work with the ACCESS-OM2 model configuration, which is so massive that it would not have been possible for one person to develop it on their own. It really needed a team behind it to look at all the aspects needed, run the simulations and to work together to analyse the output.”

“In the case of ocean modelling in Australia, we have found that by working together we can develop more accurate and complex models and that we are more productive in terms of the science outputs.  If I was doing this my own, I could evaluate how the model does in the Southern Ocean. But a global ocean – sea ice model needs input and expertise from scientists studying the North Atlantic, the tropics, air-sea interactions, sea-ice and many others.”

Dr Morrison is passionate about changing the culture of science.

“Until now, academia has been structured around the hero model, where an eminent tenured academic leads a team of junior researchers and students. The lead academic gets the credit for the team’s work and more than their share of funding. Junior researchers are only deemed successful once they themselves are tenured and become the next hero professors. This has led to a pervasive competitiveness in academia, and has driven away a lot of good researchers who aren’t driven by competition and fame.

“I prefer a more flat structure, and we have strived to implement this in our collaborative projects – at each meeting we rotate leadership, and the order of the author list is decided after the paper has been written, not at the start of the project. We treat everyone equally, it doesn’t matter if they are a researcher, a student or a software engineer. These projects have been hugely successful – it turns out many people are more motivated working in a team like this, rather than toiling away for a hero professor.”

When you don’t have observations, ask seals

Dr Morrison focuses on an area quite close to the Antarctic, known as the Antarctic margins.

Scientists know that Antarctica is melting because warm water circulates under the ice that hangs out over the ocean (also known as ice-shelves) and melts the ice from underneath, causing Antarctica to dump fresh water into the ocean, which in turn changes the ocean circulation.

“We are trying to work out why the ocean is warming and predict what will happen to the ocean circulation if we change things like the winds or the quantity of water coming from Antarctica”.

The problem is that there are barely any observations in that area of the world because ships can only access in summer and it is very far away and expensive to get them there.

“There is so much we don’t know, even without climate change just in terms of steady state circulation. The best observations we have come from seals. In the last 15 years they have been putting temperature and salinity sensors on the seals’ heads because they can swim under the sea ice, and forage down there in winter.”

Researchers also use Argo floats, which is another common way to measure the ocean globally. They float in the top 2000m of the ocean and measure temperature and salinity. However, these instruments get trapped under the sea ice, so they can’t send the data back or use GPS to track their location.

“The seals are amazing because when they need to breathe, they find the holes in the sea ice, connect to GPS and send the data back. Still, the data they produce is not very large. That is where climate models are super useful tools because they fill the gaps in the sparse observations we have.”

Currently, researchers can predict how much Antarctica is going to melt based on the models and analysis coming from the ice sheet researchers. The ice sheet models use temperature output from ocean models to provide the ocean forcing that melts the ice shelves. Ocean modellers then use the melt rate outputs from ice sheet models to investigate how ocean circulation will respond to the added meltwater.

“The problem is that we are modelling the ocean and ice sheet using separate systems, as the models are not linked yet. Coupling the ice sheet and ocean models is really important to include the effect of ice – ocean feedbacks. This is our next big step as well as connecting and collaborating between our two communities of researchers.”