Research Interests

Mesoscale convection and regional circulation

How does convection influence the regional circulation features over central and southern Africa? Guided by this question, I am addressing how representation of this convection in weather and climate models affects both regional climate and the sensitivity to remote drivers. This work is part of efforts to improve information available on local to regional rainfall variability and change and is carried out with colleagues in UK and southern Africa institutions. This research is supported by extensions to the UMFULA and IMPALA projects (co-I).

A tropical-extratropical interaction as simulated by Pan-African convection-permitting Met Office UM simulation. Animation shows OLR (greyscale) and 200 hPa circulation (streamlines).

Tropical-Extratropical Interactions

Tropical-extratropical interactions frequently produce large bands of deep convective cloud in the Southern Hemisphere subtropical convergence zones. I am working on questions related to the climate dynamics which drive interannual variability in event frequency, the answers to which, also have much bearing on diagnosing reasons underlying model biases in the SH convergence zones events in climate simulations. This work is supported by FCFA UMFULA & IMPALA projects and a Newton Fund CSSP-Brazil grant (PI).

A Tropical-Extratropical cloud band that developed over southern African 19 Jan 2010 (MSG2 IR image-courtesy EUMETSAT).

Sting Jet Windstorms

Sting jet windstorms are a high-impact mesoscale feature associated with explosively developing extratropical cyclones. Together with Prof Sue Gray and Prof Peter Clark, we have been studying the mechanisms involved in the variability of sting jets and how this relates to short-range prediction of the most severe winds. We have also worked on quantifying the contribution of sting jet windstorms to climatological windstorm risk across the North Atlantic. Ambrogio Volonte is studying the evolution of mesoscale instability associated with sting jet descents. The project "Sting Jet Windstorms in Current and Future Climates" continues earlier work by Laura Baker and Oscar Martinez-Alvarado. This work was supported by AXA-Research Fund.

Sting jet trajectory ensemble from a MetUM simulation of cyclone Friedhelm. Shading indicates number of pressure levels with conditional symmetric instability (CSI).