WWRP-THORPEXTIGGEThe THORPEX Interactive Grand Global Ensemble (TIGGE)
provides a data base of ensemble predictions from theleading global NWP centres, for scientific research on
predictability and development of probabilistic weather
forecasting methods
http://tigge.ecmwf.int

THORPEX
THORPEX is an international research programme to accelerate improvements in the accuracy andutility of high-impact weather forecasts up to two weeks ahead.
THORPEX – THe Observing system Research and Predictability EXperiment – was established in2003 by the Fourteenth World Meteorological Congress. THORPEX is part of the World Weather
Research Programme, under the auspices of the WMO Commission for Atmospheric Sciences(CAS), and is a key research component of the WMO Natural Disaster Reduction and Mitigation
Programme.
Forecasting high-impact weather
The current success of numerical weather prediction represents one of the most significant scientificachievements of the 20th century. Despite the notable increase in forecast skill over recent decades
there is room for further improvement, both in the accuracy of forecasts of high-impact weather andthe use of weather forecast information for socio-economic risk reduction.
Many weather forecast situations may be characterised as low probability/high risk – the event may
be unlikely but the consequences may be catastrophic in terms of loss of life, property damage, lossof revenue etc. Probabilistic forecasting is a powerful tool to improve early warning of such highimpact events.
TIGGE objectives
TIGGE is a major element of the THORPEX
research programme:• Enhancing collaboration on ensemble
prediction, internationally and between
operational centres and universities.
• Supporting research on weather forecasting,especially applications of ensembleforecasting.
• Enabling new probabilistic forecast products
for a future Global Interactive Forecast System(GIFS).

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Predicting flood alerts forRomania using TIGGE
Forecasting strike probabilities
for Hurricane Ike by combining
two TIGGE ensembles

The TIGGE Archive
Ensemble forecasts are collected in near-real time using a common format at three data archive anddistribution centres: China Meteorological Administration (CMA), European Centre for Medium-range
Weather Forecasts (ECMWF) and US National Center for Atmospheric Research (NCAR).

The operational forecasting centres supplying
daily global forecasts are:
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Australian Bureau of Meteorology (BoM)
Brazilian Centra de Previsao deTempo e Estudos Climatico (CPTEC)
China Meteorological Administration (CMA)The European Centre for Medium-Range
Weather Forecasts (ECMWF)
Japan Meteorological Agency (JMA)
Korea Meteorological Administration (KMA)
Meteorological Service of Canada (MSC)
Météo-France (MF)
UK Met Office (UKMO)US National Centers forEnvironmental Prediction (NCEP)

Data flow that builds the TIGGE Archives

Using TIGGE data
We invite scientists to use the TIGGE data as a resource for research projects. The data are available
for research and education after a simple electronic registration process. Access is normally provided
with a 48-hour delay after the initial time of the forecast. Access to data as soon as it becomes
available may be granted for field experiments and projects of special interest to THORPEX.
Registration for real-time access is handled via the THORPEX International Programme Office.

Data are available via the TIGGE data portals:
CMA: http://wisportal.cma.gov.cn/tigge
ECMWF: http://tigge-portal.ecmwf.int
NCAR: http://tigge.ucar.edu
Please visit the portals for further details about thefunctions and tools provided.

TIGGE data illustrates
uncertainties in a 3−day
forecast of atmospheric flow

Research using TIGGE Data
The TIGGE data set is a major resource for research and development for weather forecasting,including:• Calibration of ensemble forecasts, including bias correction and downscaling.
• Combination of ensembles produced by multiple models.
• Development of probabilistic forecast products.
• Predictability and dynamical processes.
• Hydrological applications.
This list is not exhaustive. The TIGGE website includes a full listing of TIGGE research publications.
TIGGE-LAM
To complement the global TIGGE data set, a panel of experts (called TIGGE-LAM) has been set-up toorganize a limited-area-model component of TIGGE. High-priority data from LAM ensemble prediction
systems will be also available from the three archive centres.
See http://www.smr.arpa.emr.it/tiggelam/ for more information.
Outlook
TIGGE provides the basis for the development of a future Global
Interactive Forecast System. GIFS aims to improve theprobabilistic early warnings of severe weather based on TIGGE
research and other strands of the THORPEX programme.

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GenerateProducts

As a first step, GIFS products are being developed to support
forecasts of tropical cyclones and heavy precipitation, to betested in regional Forecast Development Projects.
The TIGGE project is also developing a collaboration with theClimate Historical Forecast project(see http://www.clivar.org/organization/wgsip/chfp/chfp.php)
to address seamless ensemble forecasting from days andweeks through seasonal timescales.

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RegionalCentreNationalCentreNational
Centreusers

usersNationalCentreusersusers

Process for generating anddistributing GIFS products
Further information
The TIGGE project is managed by the THORPEX GIFS-TIGGE working group, with the support of theTHORPEX international programme office at WMO. TIGGE is also part of the Global Earth Observation
System of Systems (GEOSS).
• Further information about the THORPEX research programme is available at
http://www.wmo.int/thorpex/• For more information about TIGGE, GIFS and related research, please see the TIGGE website at
http://tigge.ecmwf.int