CLIMATE ‘MEMORY’ MAY AID LONG RANGE FORECASTS

Posted 17 March 2003

Embargoed until Monday, 24 March 2003

RESEARCHERS AT Harper Adams University College, Shropshire, believe a ‘memory’ in the climate system could be tapped to improve long-range weather forecasts.

In the April edition of ‘Weather,’ the journal of the Royal Meteorological Society, an article co-written by Dr Peter Kettlewell will show how summer rainfall levels in the UK are affected by ‘remembered’ changes in winter air pressure over the North Atlantic ocean.

The article is based upon the work of a team headed by Dr Kettlewell, a senior researcher at Harper Adams, and co-author Dr David Stephenson, Head of the Climate Analysis Group at the University of Reading. Sponsored by the Home Grown Cereals Authority (HGCA), this work has previously shown that the quality of UK wheat grain is directly affected by the climate changes over the North Atlantic Ocean. Large-scale alterations in air pressure between the northern and southern regions of the North Atlantic, known as the North Atlantic Oscillation or NAO, take place during the winter and affect the quality of wheat grain that is harvested during the following summer.

Continuing work on the phenomenon has now shown that the winter NAO affects wheat quality by influencing summer rainfall levels. High NAO levels in winter tend to be followed by a dry summer in England and Wales, while wet summers tend to be preceded by low NAO winters.

This relationship holds true for much of northwestern Europe and southern Scandinavia and has allowed Dr Kettlewell to build up a two category forecasting system, of above or below average summer rainfall.

Although, it is not yet possible to forecast exact rainfall levels, Dr Kettlewell hopes continuing studies will lead to improved long-range weather forecasts.

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Notes to Editors: (1) The full article reference is as follows: P. S. Kettlewell, D. B. Stephenson, M. D. Atkinson and P. D. Hollins (2003) Summer rainfall and wheat grain quality: Relationships with the North Atlantic Oscillation. Weather - Volume 58, Issue Number 4 (April), p.155. (2) Initial research into the effects of the NAO on wheat grain quality was conducted by Dr Peter Kettlewell and other crop scientists at Harper Adams University College and the University of Minnesota, USA. (3) Continuing research into the effect of the NAO on wheat quality has taken place as part of a project sponsored by the Home Grown Cereals Authority (HGCA) and several companies from the UK cereals industry. Dr Kettlewell’s research team at Harper Adams, working in conjunction with Dr David Stephenson’s team at the University of Reading, has conducted this further research. (4) Dr Peter Kettlewell and Dr David Stephenson will be available for comment at Harper Adams University College on Tuesday, April 1, 2003. Please contact the Press & Publications Officer Nick Barnes if you wish to arrange an interview.