European Climate Assessment

CCl/CLIVARETCCDMI meeting

Norwich, UK24-26 November 2003

Albert Klein TankKNMI, the Netherlands

Guide

1. ECA project

2. Indices

3. Daily dataset

4. Regional workshop planning

5. Available web resources

Guide

ECA project

1. Indices

2. Daily dataset

3. Regional workshop planning

4. Available web resources

ECA project

1. initiated by EUMETNET in 1998; coordinated by KNMI

2. project report issued in 2002; next report in 2006

3. daily station data collated and processed at KNMI

4. at present 41 participants from 39 countries

5. joint paper on ECA dataset published in Int. J. of Climatol, 2002

6. only reliable series kept for trend analyses

7. four common homogeneity tests applied on derived monthly and annual series (see examples)

ECA project –continued–

8. core set of indices for extremes calculated

9. public website presents all results as time series plots and trend maps >> primarily used for discussion

10. website keeps dictionary of agreed definitions for core set of indices (Peterson et al., WMO-TD1071)

11. standardization makes it easy to compare results to other regions

12. results serve as input to worldwide analyses(Frich et al., 2002; Alexander et al., in prep.)

13. results are used for impact studies (e.g. EEA)

Temperature

Precipitation

Wijngaard, Klein Tank and Können, Int. J. of Climatol., 2003

Data quality control and homogeneity

ECA website: www.knmi.nl/samenw/eca

Guide

1. ECA project

Indices

1. Daily dataset

2. Regional workshop planning

3. Available web resources

Klein Tank and Können, J. Climate, 2003

WMO status of global climate in 2002

www.wmo.ch

Relation between relative trend bq/X required for 80% detection probability (5% level) and series length Nfor extreme events with average return period Tret

Klein Tank and Können, J. Climate, 2003

21365~ retTXbq

6x

23~ NXbq

3x

Day-count indices of extremes

Easterling et al. (BAMS, 2000) in IPCC-TAR

Linear trends in rainy season, last ~50 years

“Amplified” response of very wet days

Klein Tank and Können, J. Climate, 2003

Frich et al. (Clim. Res., 2002) in IPCC-TAR

Indices –work in progress–

1. study properties of daily distributions other than expressed in core set of indices

2. consider more advanced statistical methods to supplement the ‘simple’ descriptive indices(cf. Beijing IPCC workshop)

3. consider multi-element indices and impact-specific indices

4. address the possible causes of observed trends by studying the relation with circulation (e.g. NAO)

5. compare observation results to GCM model simulations (e.g. 62mem 1940-2080 CCSM ensemble in Challenge)

Guide

1. ECA project

2. Indices

Daily dataset

1. Regional workshop planning

2. Available web resources

Daily dataset

1. at present over 900 series (Tmin, Tmean, Tmax, Precip) from 300 European stations in ECA-dataset

2. 100% available as derived indices series(cf. dataset used in Frich et al., 2002)

3. 80% available as public daily series through website >> important for additional analyses

4. ECA dataset = European contribution to GSN?

5. in case you hold daily data for Europe or Mediterranean, you should join!

Daily dataset –work in progress–

1. improve station density in data sparse areas

2. provide additional metadata on observations and sites (cf. Aguilar et al., WMO, in prep.)

3. improve data QC procedures (cf. GDCN)

4. explore homogenisation methods for daily series

5. disseminate data in netCDF/DODS for easy model comparison and in STARDEX-, GDCN-, etc. formats

6. explore possibilities for gridded data products

7. blend and auto-update station series using SYNOPs from ECMWF archive (see example)

1900 2003

interrupted station series

nearby station SYNOPs

blended series

Data blending and auto-updating

>> makes it possible to include up-to-date monitoring type of indices products; see example: 2003 summer warmth in Europe >>

Guide

1. ECA project

2. Indices

Daily dataset

Regional workshop planning

Available web resources

ECA website: www.knmi.nl/samenw/eca

Available ECA web resources

1. All information for ECA partners available at(public) website

2. website will remain operational at least until 2008(under EUMETNET contract)

3. concept can easily be shared with other regions, e.g. those of the upcoming workshops(technical support (webserver, etc.) available from KNMI)

Consider that:

1. maintenance is crucial for success:frequently update indices results (and daily data)and check links to other sites (if portal functionality)(ECA at least 6-monthly updates)

2. one should be prepared for significant amount of questions that will be generated by the website(ECA: about 10/week at 30k pageviews/week)

3. future redesign of web interface/software is necessary(at present ECA improves data access and includes monitoring type of indices products like auto-updated indices such as summer heatwave example)

the end … questions?