A rain radar image, ©BGS NERC

The DIAMET project aims to improve our ability to forecast mesoscale structures of cyclonic storms. DIAMET stands for diabatic influences on mesoscale structures in extratropical storms.

Impacts of cyclonic storms

Strong winds and heavy rain are two of the first things to come to mind when talking about extreme weather events. In the UK such weather commonly occurs in cyclonic storms, which we experience in all seasons but are more frequent in autumn and winter.

Windstorms such as Jeanette in 2002 and Erwin in 2005 are each estimated to have caused around £1bn of damage over Northern Europe. The extensive flooding in the UK at Tewksbury and Cockermouth also resulted from cyclonic storms. Thus it is very important that such storms are accurately forecast.

Better understanding of mesoscale structures

Although cyclonic storms are generally well forecast by modern weather forecasting models, the same is not so true of the details within them – and it is in the details that the extremes of weather are found. Meteorologists refer to such detail as mesoscale structures, and they include familiar concepts such as fronts as well as more exotic phenomena like sting jets (the cause of the destruction in the two windstorms mentioned above).

The DIAMET project seeks to improve the forecasting of these structures by focusing on key processes in the energy balance of the storms: the feedback between cloud processes and the dynamics, and the transfer of heat, momentum and moisture between the atmosphere and ocean.

Components of the DIAMET project

DIAMET has three main components:

  1. A field campaign, using the NERC FAAM aircraft to probe mesoscale structures in storms approaching the UK, with high-resolution modelling of these events
  2. The results of the field campaign will be used to improve the Met Office Unified Model in a few key areas (convection, air-sea fluxes and microphysics)
  3. The project is concerned with the fundamental predictability of mesoscale structures, and how best to use measured data to constrain model simulations at these scales.


Norris, J., Vaughan, G. and Schultz, D. M. (2013), Snowbands over the English Channel and Irish Sea during cold-air outbreaks. Quarterly Journal of the Royal Meteorological Society, 139: 1747–1761. doi: 10.1002/qj.2079

David M. Schultz and Joseph M. Sienkiewicz, 2013: Using Frontogenesis to Identify Sting Jets in Extratropical Cyclones. Weather and Forecasting, 28, 603–613. doi: http://dx.doi.org/10.1175/WAF-D-12-00126.1

Martínez-Alvarado, O., Joos, H., Chagnon, J., Boettcher, M., Gray, S. L., Plant, R. S., Methven, J. and Wernli, H. (2014), The dichotomous structure of the warm conveyor belt. Quarterly Journal of the Royal Meteorological Society, 140: 1809–1824. doi: 10.1002/qj.2276

Martínez-Alvarado, O. and Plant, R. S. (2014), Parametrized diabatic processes in numerical simulations of an extratropical cyclone. Quarterly Journal of the Royal Meteorological Society, 140: 1742–1755. doi: 10.1002/qj.2254

Cook, P. A. and Renfrew, I. A. (2014), Aircraft-based observations of air–sea turbulent fluxes around the British Isles. Quarterly Journal of the Royal Meteorological Society. doi: 10.1002/qj.2345

Baker, L. H., Rudd, A. C., Migliorini, S., and Bannister, R. N.: Representation of model error in a convective-scale ensemble prediction system, Nonlinear Processes in Geophysics, 21, 19-39, doi:10.5194/npg-21-19-2014, 2014.

Oscar Martínez-Alvarado, Laura H. Baker, Suzanne L. Gray, John Methven, and Robert S. Plant, 2014: Distinguishing the Cold Conveyor Belt and Sting Jet Airstreams in an Intense Extratropical Cyclone. Monthly Weather Review, 142, 2571–2595. doi: http://dx.doi.org/10.1175/MWR-D-13-00348.1

Gray, S. L., C. M. Dunning, J. Methven, G. Masato, and J. M. Chagnon (2014), Systematic model forecast error in Rossby wave structure, Geophysical Research Letters, 41, 2979–2987, doi:10.1002/2014GL059282.

Jesse Norris, Geraint Vaughan, and David M. Schultz, 2014: Precipitation Banding in Idealized Baroclinic Waves. Monthly Weather Review, 142, 3081–3099. doi: http://dx.doi.org/10.1175/MWR-D-13-00343.1

Methven, J. (2014), Potential vorticity in warm conveyor belt outflow. Quarterly Journal of the Royal Meteorological Society. doi: 10.1002/qj.2393

Key project members of DIAMET

Principal Investigator: Professor Geraint Vaughan, University of Manchester


Professor Tom Choularton, University of Manchester

Professor Martin Gallagher, University of Manchester

Dr Keith Bower, University of Manchester

Dr Paul Connolly, University of Manchester

Dr David Schultz, University of Manchester

Professor Peter van Leeuwen, University of Reading

Dr John Methven, University of Reading

Dr Sue Gray, University of Reading

Dr Bob Plant, University of Reading

Dr Ross Bannister, University of Reading

Dr Stefano Migliorini, University of Reading

Professor Doug Parker, University of Leeds

Professor Alan Blyth, University of Leeds

Professor Stephen Mobbs, University of Leeds

Dr Peter Knippertz, University of Leeds

Professor Ian Renfrew, University of East Anglia

Ms Sue Ballard, Met Office

Dr . Dale Barker, Met Office

Mr. Phil Brown, Met Office

Dr. Paul Field, Met Office

Dr. Roy Kershaw, Met Office

Mr. Malcolm Kitchen, Met Office

Dr. Humphrey Lean, Met Office

Mr. Nigel Roberts, Met Office

Dr. Richard Swinbank, Met Office

Dr. Jonathan Taylor , Met Office

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