Transcript Geen diatitel

European Climate Assessment
CCl/CLIVAR
ETCCDMI meeting
Norwich, UK
24-26 November 2003
Albert Klein Tank
KNMI, 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)
Data quality control and homogeneity
Temperature
Precipitation
Wijngaard, Klein Tank and Können, Int. J. of Climatol., 2003
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
Day-count indices of extremes
Relation between relative trend bq/X required for 80%
detection probability (5% level) and series length N
for extreme events with average return period Tret
bq X ~  Tret 365 1 2
bq X ~ N 3 2
3x
6x
Klein Tank and Können, J. Climate, 2003
“Amplified” response of very wet days
Linear trends in rainy season, last ~50 years
Easterling et al. (BAMS, 2000) in IPCC-TAR
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)
Data blending and auto-updating
1900
2003
interrupted station series
nearby station
SYNOPs
blended series
>> 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?