A stratospheric bridge linking Arctic sea ice loss to cold European winters


A stratospheric bridge linking Arctic sea ice loss to cold European winters


Project Description


Dr Hua Lu (British Antarctic Survey)

Dr Thomas Bracegirdle (BAS)

Dr. Manoj Joshi (UEA Environmental Sciences)

Prof David Stevens (UEA Mathematics)


Scientific Background

Rapid Arctic sea-ice decline has been implicated in causing more frequent extreme cold winters over Northern Europe, including the UK. Recent research suggests that the stratosphere (15-40 km above the surface) plays a crucial role in mediating such a connection. However, the stratospheric response to sea-ice loss is known to be complex, and is a key missing link in our understanding of how European climate responds to Arctic seaice changes. One possible missing element is downward wave reflection from the stratosphere. Under certain conditions, the winter stratospheric polar vortex is able to reflect so-called Rossby waves back into the troposphere. We postulate that such reflective waves mediate the dynamical coupling between Arctic sea ice and the jet stream, altering winter weather patterns over Northern Europe. Your research will pave the way for improved seasonal forecasting.

Objective & Methodology

The objective is to understand how wave reflection, and the feedbacks associated with it, connects tropospheric climate anomalies in different regions. You will carry out numerical simulations using a global circulation model to evaluate the impact of these processes on the troposphere and its climate. Novel diagnostics will be developed enabling identification of the crucial changes and positive feedback that lead to significant tropospheric responses.


You will be based at the British Antarctic Survey and receive additional supervision from the University of East Anglia. You will be trained in the theory of atmospheric dynamics, computer modelling of weather and climate, and analysis of big data, supplemented by summer schools and a diverse range of workshops. You will be guided through the process of preparing your results for publication, and will have the opportunity to present your research at national/international conferences. This project will suit an applicant with creative ideas and a desire to become a meteorologist, polar scientist, or geoscientist.


We seek an enthusiastic, proactive student with strong scientific interests and selfmotivation, who holds or expects to gain at least an upper-second class undergraduate degree in applied mathematics, atmospheric or oceanic sciences, computer science, engineering, physics, statistics or a related field. Programming experience and written skills are advantageous

The successful candidate will be registered for a PhD in the University of East Anglia’s School of Environmental Sciences.


  • Nakamura, T., K. Yamazaki, K. Iwamoto, M. Honda, Y. Miyoshi, Y. Ogawa, Y. Tomikawa, and J. Ukita (2016). The stratospheric pathway for Arctic impacts on midlatitude climate, Geophysical Research Letters, 43, 3494–3501, doi: 10.1002/2016GL068330.
  • McKenna, C. M., Bracegirdle, T. J., Shuckburgh, E. F., Haynes, P. H., & Joshi, M. M. (2018). Arctic sea ice loss in different regions leads to contrasting Northern Hemisphere impacts. Geophysical Research Letters, 45, 945–954, doi: 10.1002/2017GL076433
  • Screen, J. A., C. Deser, D. M. Smith, X. Zhang, R. Blackport, P. J. Kushner, T. Oudar, K. E. McCusker, L. Sun (2018). Consistency and discrepancy in the atmospheric response to Arctic seaice loss across climate models. Nature Geoscience, 11, 155–163, doi: 10.1038/s41561-018-0059-y.
  • Lu, H., A.A. Scaife, G.J. Marshall, J. Turner, and L.J. Gray (2017). Downward wave reflection as a mechanism for the stratosphere–troposphere response to the 11-Yr solar cycle. Journal of Climate, 30, 2395–2414, https://doi.org/10.1175/JCLI-D-16-0400.1
  • O'Callaghan, A., M. Joshi and D. Stevens (2014). The effects of different Sudden Stratospheric Warming types on the ocean, Geophysical Research Letters, 41, 7739-7745, doi: 10.1002/2014GL062179.

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