Introducing STARDEX:STAtistical and Regional dynamical

Downscaling of EXtremes for European regions

Clare Goodess* & the STARDEX team*Climatic Research Unit, UEA, Norwich, UK

February 2002 to July 2005

http://www.cru.uea.ac.uk/projects/stardex

COP10, 13 December 2004

The STARDEX team• University of East Anglia, UK • King's College London, UK• Fundación para la Investigación del Clima, Spain • University of Bern, Switzerland • Centre National de la Recherche Scientifique, France• Servizio Meteorologico Regional, ARPA-Emilia Romagna, Italy• Atmospheric dynamics group, University of Bologna, Italy• Danish Meteorological Institute, Denmark • Eidgenössische Technische Hochschule, Switzerland• Fachhochschule Stuttgart - Hochschule für Technik, Germany• Institut für Wasserbau, Germany• University of Thessaloniki, Greece

• PRUDENCE focuses on dynamical downscaling

• STARDEX is evaluating an alternative, complementary approach to providing high-resolution information: statistical downscaling (SDS)

• This approach has some advantages:– Provides station/point values– Less computer intensive than dynamical downscaling

• STARDEX is performing a rigorous and systematic inter-comparison and evaluation of SDS methods and comparison with dynamical downscaling

STARDEX is focusing on temperature & rainfall extremes:

• 10 core indices covering frequency, magnitude and persistence (the STARDEX software package calculates 57 indices in total)

• The more robust SDS methods will be used to construct scenarios of extremes for end of 21st century for 6 regions & Europe as a whole

The underlying principles of SDS:

• Observed relationships between the local surface climate and larger-scale climate (e.g., circulation patterns, atmospheric humidity) are established…

• And applied to GCM output for the future…

• On the assumption that these relationships will be unchanged in the future….

• And that the larger-scale climate is better simulated by GCMs than local climate

Greenland Anticyclone Sole Cyclone

1971-1983 (left) & 1983-1995 (right)

Examples of strong relationships between intense rainfall and

circulation established by STARDEX:

Guy Plaut, CNRS-INLN András Bárdossy, USTUTT-IWS

French Alpes Maritime German Rhine (winter)

Circulation pattern optimisation technique - CP02

So STARDEX has done a lot of work analysing observed data:

• Including a unique data set of daily station records for ~500 European stations - indices available from http://www.cru.uea.ac.uk/projects/stardex

• And denser station networks for 6 regions: Iberia, Greece, UK, German Rhine, Alps, northern Italy

1958-2000 trend in DJF frost days

Scale is days per year. Red is decreasing

AthensAthensFebruary 2004February 2004

Malcolm Haylock, UEA

1958-2000 trend in JJA heat wave duration

Scale is days per year. Red is increasing Malcolm Haylock, UEA

Property damage: US$ 13 bnProperty damage: US$ 13 bnFatalities: 27,000 (14,800 in France)Fatalities: 27,000 (14,800 in France)

Western EuropeWestern EuropeAugust 2003August 2003

1958-2000 trend in JJA heavy rain events

Scale is days per year. Blue is increasing

Central and Eastern EuropeCentral and Eastern EuropeAugust 2002August 2002

Fatalities: > 100Fatalities: > 100Economic losses: > US$18 bnEconomic losses: > US$18 bnInsured losses: > US$3 bnInsured losses: > US$3 bn

Malcolm Haylock, UEA

In part, these changes can be explained by changes in circulation

& other predictors used in SDS

E.g., Heavy winter rainfall and links with North Atlantic Oscillation/SLPHaylock & Goodess, IJC, 2004

A major, systematic inter-comparison of SDS methods is underway in STARDEX:

20+ methods, 7 regions, 13 indices and 4 seasons

Iberian Peninsula – Spearman correlations for 6 SDS models and 4 seasons averaged across 7 extreme rainfall indices and 16 stations

Neural network methods perform best in this example – but skill always varies betweenseason & index

Malcolm Haylock, UEA

• Currently drawing up recommendations on the most appropriate downscaling methods and guidance for users (building on IPCC guidelines)

• And constructing future scenarios….

• Will summarise changes and their reliability for a broader audience

STARDEX has 7 months to go:

STARDEX outputs, in a variety of formats for different audiences, are available from the web site:

http://www.cru.uea.ac.uk/projects/stardex

e.g., information sheets (2-sides A4)