Lead Supervisor: Oscar Martínez-Alvarado, National Centre for Atmospheric Science (NCAS) and Department of Meteorology, University of Reading
Co-supervisors: Ben Harvey, National Centre for Atmospheric Science (NCAS) and Department of Meteorology, University of Reading; Ambrogio Volonté, National Centre for Atmospheric Science (NCAS) and Department of Meteorology, University of Reading; Richard Dixon, Inigo Insurance / Visiting Research Fellow, University of Reading
Figure 1. Windstorm Eunice as it approached the UK on 18 February 2022: (a) Near-surface wind speed, and (b) infrared satellite imagery from the SEVIRI instrument on board the MSG satellite.
Windstorms, a particularly hazardous form of the low-pressure systems that typically occur in the mid-latitudes in the autumn and winter, are one of the most important natural hazards impacting the UK. Their associated strong surface winds and gusts can lead to economic loss and loss of life. Windstorms Eunice in February 2022 (Fig. 1; Volonté et al. 2023a,b) and Agnes in September 2023 are two examples of recent windstorms impacting the UK.
While climate projections strongly suggest a reduction in the total number of windstorms per year, several studies have highlighted a risk increase associated with the most intense of these storms (Martínez-Alvarado et al. 2018, Manning et al. 2023). However, both the uncertainty associated with these projections and the mechanisms driving these effects are not yet well understood.
Windstorm hazards are generated by near-surface airstreams within these cyclones, whose characteristic length scales range from a thousand to a few tens of kilometres. The airstreams at the smaller “mesoscale” length scales represent a research challenge as they cannot be represented by climate models unless these have sufficiently high resolution. While, this requirement is not yet met by even state-of-the-art global climate models, recent research using very high-resolution models has shown the importance of representing mesoscale features by revealing risk differences with respect to lower-resolution models (Manning et al. 2023). However, the physics behind these differences have not yet been fully investigated.
This project will address the following science questions:
- What is the uncertainty due to internal variability in projections of wind hazards associated with mid-latitude cyclones?
- How do large-scale changes over the North Atlantic affect the risk associated with windstorms impacting the UK?
- What proportion of the expected changes in cyclone-related wind hazard is driven by synoptic-scale processes and what proportion is driven by mesoscale processes?
The first question deals with the quantification of uncertainty due to internal variability. The second question deals with the impact of changes in drivers over the North Atlantic, such as changes in the North Atlantic jet (Harvey et al. 2023), on the development of windstorms. We know that particularly strong windstorms tend to originate at lower latitudes (e.g., Martínez-Alvarado et al. 2018), possibly linked to hurricanes and post-tropical cyclones (Sainsbury et al. 2022). Therefore, there is scope to investigate whether active North Atlantic hurricane seasons with warm sea surface temperature and frequent tropical cyclones increase the early-season extra-tropical cyclone risk and increase correlation between these two perils. The third question deals with changes in processes within windstorms themselves, such as changes in moisture availability leading to exacerbated latent heating processes in clouds.
The project offers an exciting opportunity to investigate brand-new climate datasets with techniques that have not been used in the context of climate change research before. The new datasets, whose production is being led by the project’s supervisors, consists of a large set of simulations of windstorms produced using a high-resolution weather forecasting model driven by atmospheric states obtained from many plausible realisations of the future climate out to the end of the century. The analysis techniques involve newly developed diagnostics to classify storms and assess the likelihood of occurrence of mesoscale airstreams such as sting jets (descending airstreams potentially leading to strong surface winds and gusts). Furthermore, bespoke diagnostic output will enable the atmospheric processes involved in these storms (such as latent heating in clouds) to be interrogated.
The project will be associated with the CANARI programme, involving seven research centres and scientists with a wide-ranging expertise, including hydrologists, oceanographers and groundwater scientists. The student will have the opportunity to collaborate with these scientists to learn about the broader implications of climate change to the UK and Europe. The project will be developed in collaboration with Inigo insurance, a global specialist of high-risk, high-capacity insurance and reinsurance. The collaboration includes a three-month placement to learn on-the-job how science results are used in an industrial context. These activities are optional and can be adjusted to suit the student’s circumstances.
We are seeking a highly self-motivated student with an interest in the relationship between atmospheric dynamics, high-impact weather and climate change. Prospective students will also have an interest in developing science without losing view of its consequences on and applications to everyday life. The project will be suitable for students with an academic first degree on a subject with a substantial level of numeracy (e.g., meteorology, mathematics, physics, engineering or other closely related environmental of physical science). The project’s supervisors are committed to the improvement of diversity and inclusion in environmental sciences. All applications will be very welcome.
This project has CASE support from Inigo Insurance
Harvey, B., Hawkins, E., & Sutton, R. (2023). Storylines for future changes of the North Atlantic jet and associated impacts on the UK. International Journal of Climatology.
Manning, C., Kendon, E. J., Fowler, H. J., & Roberts, N. M. (2023). Projected increase in windstorm severity and contribution from sting jets over the UK and Ireland. Weather and Climate Extremes, 40, 100562.
Martínez-Alvarado, O., Gray, S. L., Hart, N. C., Clark, P. A., Hodges, K., & Roberts, M. J. (2018). Increased wind risk from sting-jet windstorms with climate change. Environmental Research Letters, 13, 044002.
Sainsbury, E. M., Schiemann, R. K., Hodges, K. I., Baker, A. J., Shaffrey, L. C., & Bhatia, K. T. (2022). Why do some post-tropical cyclones impact Europe?. Monthly Weather Review, 150, 2553-2571.
Volonté, A., Gray, S. L., Clark, P. A., Martínez‐Alvarado, O., & Ackerley, D. (2023a). Strong surface winds in Storm Eunice. Part 1: storm overview and indications of sting jet activity from observations and model data. Weather.
Volonté, A., Gray, S. L., Clark, P. A., Martínez‐Alvarado, O., & Ackerley, D. (2023b). Strong surface winds in Storm Eunice. Part 2: airstream analysis. Weather.