This week we will be looking at Eswyn Chen’s dissertation. Eswyn is a third year Geographer at Wolfson, and her dissertation is focused on changes in the North-Atlantic jet streams.
What is your dissertation about?
My dissertation is about the changes in the position and waveform of the North Atlantic jet streams, which are bands of fast-moving westerlies just below the tropopause, over the satellite era. To find out how much and in what manner the jets have moved, I need to determine the latitudinal location of their maximum wind speed for each of the summer months over the past 40 years, by processing atmospheric reanalysis data on Matlab using a code that finds the maxima of speeds through space. The time series generated will be statistically compared against CMIP6 model data to see how well the observed excursions are represented in current climate models.
Why is this important?
The North Atlantic jet streams strongly influence regional synoptic conditions by steering weather systems across North America and Western to Central Europe. Coumou et al. (2015) demonstrated that the Northern Hemisphere summer jet has weakened in recent decades, and the hypothesis is that this could lead to the persistence and intensification of extreme heat events (Horton et al., 2015), as weather systems get increasingly ‘stuck’ on the weakened jet stream. There’s a need to clarify the links between jet and temperature anomalies and for climate models to capture these relationships and predict future changes accurately.
How did you find conducting your research remotely?
It was always meant to be desk-based so I didn’t have to change my plans. However, I do find getting in-person technical support more difficult than usual, when the project involves using a programme that isn’t taught in the course, and the processing of an amount of data that exceeds the capacity of my personal laptop. The former can be fixed with some self-learning, but the latter requires a lot more coordination between people in order to access either help or hardware.
What would be your advice to current second years planning their dissertation?
Your dissertation would open up lots of opportunities to acquire new skills and knowledge beyond the curriculum. I’m doing more physics than geography in mine! There’s always a learning curve, which is why you need to pick something you’re really interested in so that you stay motivated in the face of hurdles. The other thing is that discussing and working out the methods/project design (as well as contingency plans) early on with your supervisors would save a lot of unnecessary/additional panic later on, as you’ll just need to follow it through.
Image credits: Eswyn Chen
Bibliography:
Coumou, D., Lehmann, J. and Beckmann, J. (2015). The weakening summer circulation in the Northern Hemisphere mid-latitudes. Science, 348(6232), pp.324-327.
Horton, D., Johnson, N., Singh, D., Swain, D., Rajaratnam, B. and Diffenbaugh, N. (2015). Contribution of changes in atmospheric circulation patterns to extreme temperature trends. Nature, 522(7557), pp.465-469.
DISCLAIMER: THE VIEWS EXPRESSED IN THIS ARTICLE ARE THOSE OF THE AUTHOR ONLY AND DO NOT REPRESENT THE VIEWS OR OPINIONS OF COMPASS MAGAZINE AS A WHOLE OR THE UNIVERSITY OF CAMBRIDGE DEPARTMENT OF GEOGRAPHY.