The Global Precipitation Climatology Centre (GPCC) Serving the Hydro-Climatology Community Bruno Rudolf, Andreas Becker , Udo Schneider , Anja Meyer-Christoffer, Markus Ziese, Peter Finger D t h W tt di t Deutscher Wetterdienst Department of Hydrometeorology Global Precipitation Climatology Centre 1
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The Global Precipitation Climatology Centre (GPCC) Serving ( ) g
the Hydro-Climatology Community
Bruno Rudolf, Andreas Becker, Udo Schneider, , , ,Anja Meyer-Christoffer, Markus Ziese, Peter Finger
D t h W tt di tDeutscher WetterdienstDepartment of Hydrometeorology
Global Precipitation Climatology Centre 1
GPCCGPCC
Outline
• Background and functions of the Global Precipitation Climatology Centre• Background and functions of the Global Precipitation Climatology Centre (GPCC)
• GPCC data base and provenancep
• Methods in use for QC and gridding
• GPCC Products
• Sampling error vs. high-resolution products and trend analysis
• Frequencies of extreme eventsq
• Outlook
Global Precipitation Climatology Centre 2
GPCCGPCC
Outline
• Background and functions of the Global Precipitation Climatology Centre• Background and functions of the Global Precipitation Climatology Centre (GPCC)
• GPCC data base and provenancep
• Methods in use for QC and gridding
• GPCC Products
• Sampling error vs. high-resolution products and trend analysis
• Frequencies of extreme eventsq
• Outlook
Global Precipitation Climatology Centre 3
GPCCGPCC
The Global Precipitation Climatology Centre (GPCC)
Established by the World Meteorological Organization WMO in the year 1988
undertaken by Deutscher Wetterdienst DWD
contributes to the Global Climate Observing System GCOS and the World Climate Research Programme WCRPg thousands of users world-wide scientific task: quantitative assessment of global precipitationq g p p
and investigation of the global water cycle
Global Precipitation Climatology Centre 4
GPCCGPCC
The functions of the GPCC
collection of observed precipitation data world-wide
data processing, quality control, storage
data analysis, production of gridded data fields
distribution of the gridded data fields distribution of the gridded data fields
contribution to international programs contribution to international programs
Global Precipitation Climatology Centre 5
GPCCGPCC
Outline
• Background and functions of the Global Precipitation Climatology Centre• Background and functions of the Global Precipitation Climatology Centre (GPCC)
• GPCC data base and provenancep
• Methods in use for QC and gridding
• GPCC Products
• Sampling error vs. high-resolution products and trend analysis
• Frequencies of extreme eventsq
• Outlook
Global Precipitation Climatology Centre 6
data sourcesGPCC data sources
Near real-time regularly exchanged data
GPCC
• hourly/daily weather reports (SYNOP)
Near real time regularly exchanged datavia the WMO Global Main Telecommunication Network
hourly/daily weather reports (SYNOP) ca. 6,500 stations
• monthly climatological totals (CLIMAT)o t y c ato og ca tota s (C ) ca. 2,300 stations
ca. 8,000 stations ca. 8,000 stations
Non real-time:Non real time:Additional data received from ca. 190 countries
• Historical data collections (CRU FAO GHCN)plus: • Historical data collections (CRU, FAO, GHCN)• International project data (GEWEX and other)
plus:
totally more than 64 000 stations
Global Precipitation Climatology Centre 7
totally more than 64,000 stations
GPCC data baseGPCC data base
Data coverageData coverageby country
Global Precipitation Climatology Centre 8
GPCC data baseGPCC data base
More than 64,000 stations providing normal means – status 2010More than 64,000 stations providing climatic means – status 2010/10
Global Precipitation Climatology Centre 9
Data used as climatologic background for GPCC gridded data sets
GPCCGPCC
Outline
• Background and functions of the Global Precipitation Climatology Centre• Background and functions of the Global Precipitation Climatology Centre (GPCC)
• GPCC data base and provenancep
• Methods in use for QC and gridding
• GPCC Products
• Sampling error vs. high-resolution products and trend analysis
• Frequencies of extreme eventsq
• Outlook
Global Precipitation Climatology Centre 10
GPCC quality controlSeparate storage of the data from different sources
GPCC quality control
The source specific storage of the data serves an important basis for quality control as well as p q yfor understanding, traceability and later re-production
Global Precipitation Climatology Centre 11
GPCC quality controlQuality-control with 4 levels:
GPCC quality control
1a: Pre-control of SYNOPs 1b: Pre-control of CLIMATs 1c: Format check of individual1c: Format-check of individual data sets 2: Overall visual control of2: Overall visual control of individual data sets 3: Check of station meta data during the loading process
4: Semi-automatic QC of
monthly precipitation data: monthly precipitation data: Statistical pre-control and visual check of questionables
Global Precipitation Climatology Centre 12
griddingGPCC
Gridding of the station data for individual months
griddingGPCC
Gridding of the station data for individual monthsLong term mean monthly precipitation ‘normals’
Monthly precipitation anomaly gridded from station anomaliesprecipitation normals gridded from station anomalies
Gridded monthly precipitation totals
Global Precipitation Climatology Centre 13
precipitation totals
GPCCGPCC
Outline
• Background and functions of the Global Precipitation Climatology Centre• Background and functions of the Global Precipitation Climatology Centre (GPCC)
• GPCC data base and provenancep
• Methods in use for QC and gridding
• GPCC Products
• Sampling error vs. high-resolution products and trend analysis
• Frequencies of extreme eventsq
• Outlook
Global Precipitation Climatology Centre 14
GPCC products
GPCC near real-time products
GPCC products
pRoutinely produced gridded data setsavailable within: application: number of stations:
5 days First Guess Anomalies drought monitoring FAO ~ 6,500
available within: application: number of stations:
2 months Monitoring Product WCRP/GEWEX early reference ~ 7,500
Additional information provided for monitoring product• Number of stations per grid box
Schedule for the release of new products Global Precipitation Mean Climatology
i d 1951 2000- period 1951-2000- based on about 64,000 stations Nov 2010
Full Data Reanalysis Version 5- period 1901-2009
b d ll il bl d t (64 000 t ti ) N 2010- based on all available data (64,000 stations) Nov 2010
Trend analysis for selected data time-series - period 1951-2005- based on complete data time-series (~ 16,000 stations) early 2011
publication of the methods used and results to be submitted early 2011
Global Precipitation Climatology Centre 16
to be submitted early 2011
GPCC data baseTemporal data coverage Full Data Product Version 4 and Version 5
GPCC data base
Global Precipitation Climatology Centre 17
GPCCGPCC Product examples: GPCC Product examples:
GPCC
a) First Guess Analysis for August 2010 (total & anomaly)a) First Guess Analysis for July 2010 (total
Global total patterns typical for La Nina season
Global Precipitation Climatology Centre 18
Global total patterns typical for La Nina seasonAnomalies across Indian sub-continent contain precipitation causing Pakistan flooding
GPCC P d t lGPCCGPCC Product examples:
b) Monitoring (top row) and (c) Full Data Product El Nino Winter 1997/98
GPCC
Please note the excellent overall quality of the monitoring product available 2 months
Global Precipitation Climatology Centre 19
Please note the excellent overall quality of the monitoring product available 2 months after the fact, but also the improvement in the Full Data Product across central Africa!
GPCCGPCC
Outline
• Background and functions of the Global Precipitation Climatology Centre• Background and functions of the Global Precipitation Climatology Centre (GPCC)
• GPCC data base and provenancep
• Methods in use for QC and gridding
• GPCC Products
• Sampling error vs. high-resolution products and trend analysis
40 stations per grid40 stations per grid required !!
Figure: GPCC after Jenne and Joseph
Global Precipitation Climatology Centre 21
Jenne and Joseph,WMO-No. 115, 1985
station densityGPCC station densityGPCC
Monthly precipitationerror < 10%error < 10%
16 stations per grid,per grid,
i.e. approximately 40 000 stations
required globallyq g y
GPCC Climatology 1951-2000: Number of stations per 1º grid cellgy p g
Global Precipitation Climatology Centre 22
Areas in dark green and blue = Sufficient station density
station densityGPCC station densityGPCC
DailyDaily precipitationerror < 20%
40 stations per grid required !!
i e approximatelyGPCC, Monitoring Product, Sep 2009: No. of stations per 2,5º grid cell i.e. approximately100 000 stations
required globally!!
, g , p p , g
Global Precipitation Climatology Centre 23
globally!!Areas in blue = Sufficient station density
Daily data analysisDaily data analysis
- 0.40
- 0.31
- 0.04
0 04
Linear trend (slope) for number of days with daily precipitation of- 0.04 daily precipitation of 30 mm/d or more
i d 1931 2008- 0.17- 0.24
period 1931-2008
- 0.55
- 0.18
0 78 decreasearea size ca. 50x50 km2- 0.78
- 0.18
decrease ca. 50x50 km2200 - 400 msl
Global Precipitation Climatology Centre 24
Daily data analysis
+ 0 55
Daily data analysis
+ 0.92+ 0.55
+ 1 05
+ 0.15
+ 0 07
Linear trend (slope) for number of days with daily precipitation of
+ 0.36 + 0.30
+ 1.05
+ 1.37+ 0.52+ 0.34
+ 0.07 daily precipitation of 30 mm/d or more
i d 1931 2008+ 0.26 + 0. 73
+ 1 55
+ 1.62 period 1931-2008
+ 0.33+ 1.55+ 2.03
+ 0.80+ 0.95
+ 0 86
+ 0.46
+ 0.46+ 0.29
+ 0.86
+ 0.65+ 0 17
increase area size ca. 50x50 km2
+ 0.45+ 0.17 ca. 50x50 km2
200 - 400 msl
Global Precipitation Climatology Centre 25
Daily data analysis
+ 0 55
Daily data analysis
- 0.40
- 0.31
- 0.04
0 04
+ 0.92+ 0.55
+ 1 05
+ 0.15
+ 0 07
Linear trend (slope) for number of days with daily precipitation of
+ 0.36
- 0.04
+ 0.30
+ 1.05
+ 1.37+ 0.52+ 0.34
+ 0.07 daily precipitation of 30 mm/d or more
i d 1931 2008+ 0.26 + 0. 73
- 0.17- 0.24
+ 1 55
+ 1.62 period 1931-2008
all 37 stations
+ 0.33- 0.55
- 0.18
+ 1.55+ 2.03+ 0.80+ 0.95
+ 0 86
0 78 + 0.46
+ 0.46+ 0.29
+ 0.86
+ 0.65+ 0 17
increasedecrease
area size ca. 50x50 km2- 0.78
- 0.18
+ 0.45+ 0.17 decrease ca. 50x50 km2
200 - 400 msl
Global Precipitation Climatology Centre 26
GPCCGPCC
Outline
• Background and functions of the Global Precipitation Climatology Centre• Background and functions of the Global Precipitation Climatology Centre (GPCC)
• GPCC data base and provenancep
• Methods in use for QC and gridding
• GPCC Products
• Sampling error vs. high-resolution products and trend analysis
• Frequencies of extreme eventsq
• Outlook
Global Precipitation Climatology Centre 27
1955-1964 1965-1974 1975-1984 1985-1994 1995-2004
SUUMMER Number of days with heavy rain (i.e. days with totals exceeding 60 mm) for decades
WIINTTE
Global Precipitation Climatology Centre 28
R
1955-1964 1965-1974 1975-1984 1985-1994 1995-2004
SUUMMER Number of dry days (i.e. days with totals less than 1 mm) for decades
WIINTTE
Global Precipitation Climatology Centre 29
R
GPCCGPCC
Outline
• Background and functions of the Global Precipitation Climatology Centre• Background and functions of the Global Precipitation Climatology Centre (GPCC)
• GPCC data base and provenancep
• Methods in use for QC and gridding
• GPCC Products
• Sampling error vs. high-resolution products and trend analysis
• Frequencies of extreme eventsq
• Outlook
Global Precipitation Climatology Centre 30
GPCCGPCC
Further Outlook:•GPCC Climatology 2010 and Full Data Product Version 5 (almost done)•Peer-reviewed publication on GPCC data base (ASAP)•Peer-reviewed publication on GPCC data base (ASAP)•Upload to IPCC portal – Contribution to IPCC (Q1 2011)
•Selection of homogeneous time series for assembling a new homogenizedSelection of homogeneous time series for assembling a new homogenized precipitation re-analysis (HOMPRA) (Year 2011)
•Commence near real-time daily SYNOP-based Products (Year 2011)•Extend daily analysis to re-analysis of historical data (from 2011 ongoing)
Global Precipitation Climatology Centre 31
GPCC Web siteAccess to GPCC‘s Precipitation Products
Dr. Andreas Becker (scientist, head of GPCC)Udo Schneider (scientist)( )Anja Meyer-Christoffer (scientist)Markus Ziese (scientist new member)Markus Ziese (scientist, new member)Peter Finger (programmer)P t St d (t h i i )Peter Stender (technician)Astrid Heller (technician)Jan Niclas Breidenbach (technician)Dr. Bruno Rudolf (supervisor, dir. dept. hydrometeorology)
Global Precipitation Climatology Centre 33
…
GPCCGPCC
Additional Material:
Global Precipitation Climatology Centre 34
GPCC data basThe data base Jan 1901 – Oct 2010 for gridded products
GPCC data basg
Global Precipitation Climatology Centre 35
GPCC data sourcesTemporal data coverage of the eight different data sources and the total
GPCC data sources
GTS = near realtime
Global Precipitation Climatology Centre 36
near realtimeSYNOP, CLIMAT
GPCC gridding
Gridding of the stations monthly long-term mean data
GPCC gridding
g y g1. Interpolation of station based monthly normals to gridpoint normals
(distance of the grid-points 0.25° lat/lon)
2. Calculation of area-mean precipitation for regular grid-boxes for all continents and islands(grid si e 0 5° lat b 0 5° lon 1 0° lat b 1 0° lon and 2 5° lat b 2 5° lon
Gridding of the gauge data for individual months (e.g. July 2010)
(grid size 0.5° lat by 0.5° lon, 1.0° lat by 1.0° lon, and 2.5° lat by 2.5° lon
1. Calculation of precipitation (mm/month) anomalies on the stations usingall available data
2 Interpolation of station based monthly anomalies to grid point anomalies2. Interpolation of station based monthly anomalies to grid-point anomalies and calculation of area means on the grid-boxes (as above)
3. Calculation of area-mean precipitation totals for the grid-boxes bybi ti f th idd d li d lcombination of the gridded anomalies and normals
The anomaly-based interpolation is used at the GPCC since 2008
Global Precipitation Climatology Centre 37
The anomaly based interpolation is used at the GPCC since 2008
GPCC quality controlLoading new data – check station meta data against the existing data
GPCC quality control
Station with new data
base
he d
ata
bon
s in
thst
atio
decision support
optio
ns
Questionable Meta Data Expert Decision
Global Precipitation Climatology Centre 38
o Expert Decision
GPCC quality controlGPCC quality control
Metadata and precipitation observation data are intensively
lit t ll d d if
Major challenges:• Incorrect station location;
S ti f i i quality controlled and – if necessary – corrected by GPCC based on automatic as well as
• Separation of missing values from 0 mm;
• Separation of true from
Global Precipitation Climatology Centre 39
manual QC procedures false extremes;
GPCC quality controlGPCC quality controlData errors discovered by comparisons and homogeneity tests
Barisal, Maijde Court, Comilla/BGD: GHCN data
Save/BEN: Reg. data for 1922-1924 and1927 1936 too large by a factor of 2 54!!
, j ,for 1991-2000 too small by a factor*10!!
Puna/BOL: FAO and GHCN data 1930-
1927-1936 too large by a factor of 2.54!!
Puna/BOL: FAO and GHCN data 1930-1948 do not belong there!! Cantillan/PHL: Nat. data
1977-1982 all „0“!!
Puerto Puyuhuapi, Coyhaique/CHL:Nat. data 1992-1995 all „0“!!
Global Precipitation Climatology Centre 40
GPCC
Free access to GPCC gridded data sets via internet