WORLD METEOROLOGICAL ORGANIZATIONCOMMISSION FOR ATMOSPHERIC SCIENCESINTERNATIONAL CORE STEERING COMMITTEEFOR THORPEX
Eighth Session
DWD, Offenbach (2 – 4 November 2009)

CAS/ICSC-8/DOC3.3(13 IX.2009)
Item: 3.3

Report of GIFS-TIGGE WG(Submitted by Zoltan Toth and Richard Swinbank)1.

Summary

Currently all ten global weather prediction centres are providing ensemble forecasts to thethree TIGGE data archive centres. All three global archive and data portal centres(ECMWF, NCAR and CMA) have all now been operational for at least one year. The
archives contain data starting in October 2006, so now contain data for more than three
years from some providers. Under a simple registration process access is given with adelay of 48 hours after the initial time of the forecast. Real time access is granted in somecases e.g. for field experiments and projects of special interest. Registration for real time
access is handled by the WWRP-THORPEX International Programme Office at the WMO.
The number of users is currently over 200 (combining the number of users of all threearchive centres) – although this is thought to underestimate the number of active users of
TIGGE data, since some users access ithe data via other routes. A general announcementthat the TIGGE capability and service is available to users was made via the AGU
publication EOS – see Annex 1.
Early science results indicate that multi-model ensemble forecasts are in general better than
the forecasts of the best component system. The benefit appears to be clearer for fields
such as surface air temperature, but only marginal for dynamical variables such as sea levelpressure or geopotential height. Furthermore, the gain is highly variable depending on
component systems, parameters, forecast ranges and bias corrections applied. Moreresearch is needed to establish the cost/benefits of operational multi-model systems.
Research papers based on the TIGGE data set are now starting to be published in peerreviewed journals.
A TIGGE-LAM expert panel has been set up to define arrangements for TIGGE-LAM
databases, building on the global TIGGE arrangements as much as possible. The priority
here is to develop standard formats enhancing the interoperability of the existing systems.
Another objective is to facilitate the use of lateral boundary conditions from various global
systems by limited–area models.
TIGGE is paving the way towards a Global Interactive Forecasting System (GIFS). An
urgent development to make GIFS a reality is to accelerate data exchange between thepartners and a phased approach has been adopted. A pilot project, based on the real-timeexchange of tropical cyclone tracks, was succesfully run during the T-PARC field
programme. In order to carry this work forward, it is proposed to establish a GIFS Researchand Development Project (GIFS-RDP). The GIFS-RDP will provide a framework for theexperimental provision of products to enhance the prediction of high-impact weather. It isplanned that GIFS-RDP will initially operate alongside regional subprojects of the CBS
Severe Weather Forecast Demonstration Project (SWFDP) This will enhance links between
WWRP-THORPEX GIFS and the operational weather forecasting community, and allow
products based on TIGGE forecasts and multi-model ensemble to supplement the data
available from the SWFDP to operational forecasters. Objective verification and user
evaluation of the GIFS products will be a key part of GIFS-RDP. For further details, see thedraft GIFS-RDP proposal (item 7.2).

CAS/ICSC-8/Doc.3.3, p. 2
2.

Meetings

The Third THORPEX International Science Symposium, held in Monterey in September
2009, included a TIGGE user workshop. The components of the TIGGE user workshop
included:• A joint presentation on the TIGGE archive on behalf of the three archive centres• Hands-on user demonstrations of how to access the TIGGE archive byrepresentatives of all three data centres• The opportunity for users to provide feedback to archive centres and data providers.
• Presentations on some early results of research based on TIGGE data.
• Presentation and discussion of plans for the development of GIFS.
• The opportunity to get involved in focus groups to contribute to technicaldevelopments for GIFS.
The GIFS-TIGGE working group held a brief meeting after the symposium session on 15th
September. Minutes of this meeting are shown in Annex II.
A longer working group meeting is proposed in which details of plans for GIFS and the
GIFS-RDP will be discussed with other interested parties, including WWRP, THORPEX,
CBS and representatives of other THORPEX regional committees and working groups. This
meeting is expected to take place in Geneva in February 2010.
.
To develop detailed technical solutions in support of the technical implementation of GIFS
and the GIFS-RDP (including generation of different products, such as TC, PQPF), it is
proposed to create two focus groups:• Focus Group 1: Access to and distribution of real time and archived ensemble data
• Focus Group 2: Ensemble-based products and services for high impact events
During the THORPEX science symposium an additional meeting was held for those who
were interested in participating in either of the GIFS focus groups. Further details of thismeeting are given in Annex III.

CAS/ICSC-8/Doc.3.3, p. 3
ANNEX I
Improving High Impact Weather Forecasts
To accelerate improvements in 1-day to 14-day high impact weather forecasts, the World
Meteorological Organization’s (WMO) World Weather Research Programme established theObserving System Research and Predictability Experiment (THORPEX) Interactive Grand
Global Ensemble (TIGGE) in 2005. The key objectives of TIGGE are enhanced international
collaboration on ensemble prediction, determining new methods for combining ensembles
from different sources, gaining a deeper understanding of forecast error and the feasibility ofinteractive ensemble systems, and developing a prototype for a future Global Interactive
Forecasting System (GIFS).
Scientific data needs and technical implementation for TIGGE were first considered in byinternational representatives from many weather prediction and weather research centers.
A two-phased approach was planned. In phase 1, which became operational in 2006, thedata are collected in near real-time at centralized TIGGE Archive Centers and redistributed
worldwide with a short delay. In Phase 2, which is now proposed to begin in 2009, archiving
will be decentralized (widely distributed), with more focus on real-time access directly fromthe data providers through a common interface employing Web-based technologies. Here,
we report on the implementation and status of Phase 1.
Building Weather Forecast Archives
Three archive centers have been formed to receive, archive, and distribute ensemble model
weather forecast data from 10 international data providers (Table 1). The TIGGE archive
centers are hosted at the China Meteorological Administration (CMA), the European Center
for Medium-Range Weather Forecasts (ECMWF), and the National Center for AtmosphericResearch (NCAR).
The international community has recognized and agreed that the collection of ensemble data
products needs to be as homogeneous as possible to make research easy across multiple
forecast systems. To that end, it was agreed that a set of 73 gridded meteorological data
fields would constitute the TIGGE standard collection: 28 single level fields, five fields oneight pressure levels between 1000 and 200 hectopascals, geopotential height at 50
Hectopascals, potential vorticity (PV) on the 320°K potential temperature surface, and threefields on the ± 2.0 PV surface. Details about the parameter fields are in the electronic
supplement to this Eos issue (http://www.agu.org/eos_elec/). The new WMO Gridded Binary(GRIB) Edition 2 data format was chosen for TIGGE because the format is designed to holdensemble data. ECMWF brought together these details by defining lists of GRIB2 codes,
creating tables and templates for each parameter, and obtaining clarification and acceptancefor new parameters from WMO.
Data providers are encouraged to submit all of the standard fields, but they are not required
to do so. Details about the current state of archive completeness are in the electronic
supplement. Several other data archive dimensions are independently determined by theproviders and reflect their forecast systems: number of forecasts per day, forecast duration,and number of ensemble members (Table 1). Data providers are free to upgrade theirensemble prediction systems and are requested to coordinate changes with the archive
centers. Metadata describing the changes are maintained and made accessible by the data
providers. After a testing period, the first data arrived at the archive centers in October 2006,
and by February 2008 all 10 providers were adding to the TIGGE Archives.
The Unidata Internet Data Distribution, Local Data Manager (IDD/LDM)(http://www.unidata.ucar.edu/) system is the primary data transport mechanism used
between the archive centers. Some data providers also use IDD/LDM, and others use FTP
and HTTP computer protocols to deliver data to the archives in near real-time. Details about

CAS/ICSC-8/Doc.3.3, p. 4
modes of data transport are shown in the electronic supplement. The data transport is about
1.6 million data fields and 240 gigabytes per day to NCAR. ECMWF and CMA receive
somewhat less data because they perform dual roles as archive centers and data providers.
The centers receive and share data every day, and to the greatest extent possible they haveidentical archives.
Access to the Archives
TIGGE data are available to the public for noncommercial research, with a 48-hour delay
after the forecast initialization time. Electronic registration and acceptance of the data policy
is required for all users. Exceptions to these requirements are granted from the THORPEXInternational Program Office, e.g. data support for field projects.
The data access interfaces at all three archive centers are similar; however, the systems
behind each interface vary considerably. At the ECMWF TIGGE Web site(http://tigge.ecmwf.int), users can access a comprehensive set of technical and backgrounddocuments, news, archive monitoring metrics, and the link to the data access portal. Data
access services are provided by the ECMWF Meteorological Archival and Retrieval Systemand thus users can freely select date ranges from the full period of record, spatial subsettingfrom the global domain, individual parameter selection, and interpolation across multiple
center native grids to a uniform resolution. The output data format is GRIB2.
The NCAR TIGGE portal (http://tigge.ucar.edu/) provides access to the most recent two
weeks of data through multiple options. Interfaces are available to browse the archive andselect forecast files for download, or individual parameters, spatial subsets from the global
domain, and user specified grid resolution across multiple centers. Additionally, online data
are stored in a directory and file structure system and are available for direct download. The
forecast files are only available in GRIB2 format, while users have the option of selecting
either GRIB2 or netCDF (Network Common Data Form) output format through the subsettinginterface. A selection of tools that perform data access and analysis are listed with links inthe portal. Persons with NCAR computing privileges have access to the full period of record.
For others, offline files can be restaged for online access.
The TIGGE portal at CMA (http://wisportal.cma.gov.cn/tigge/) has features in common withthose at ECMWF and NCAR. The portal offers the most recent 10 days of data and aninterface for specifying subsetting (temporal range, parameter, levels) across the provider
centers. The interface also provides a way to monitor the data processing status and to
download data by HTTP and FTP protocols.
The archive centers have had strong collaboration with each other in areas of efficient datatransport methods, software for archive preparation, and interface development. The centers
interlink with each other, and a community TIGGE user group Web forum(http://www.unidata.ucar.edu/forums/forum.jspa?forumID=5) has been created for broaduser information exchange.
Modest archive and user access improvements will continue to be implemented at the
TIGGE archive centers as resources and specific user needs become apparent.
International coordination for TIGGE Phase 1 and for the forthcoming Phase 2 is through the
GIFS-TIGGE working group. The working group meets annually, occasionally in conjunction
with other THORPEX meetings. Meeting reports are available from the ECMWF Web site. In
March 2009, the TIGGE working group meeting will be expanded to include a users
workshop. The meeting date and location will be posted on the archive center portals when
they are determined. [Note – the user workshop took place as part of the THORPEX science
symposium in September 2009.]
Acknowledgments
NCAR is sponsored by the U.S. National Science Foundation. The TIGGE working groupinternational representatives and major contributing partners at the archive centers are listed
in the electronic supplement.

CAS/ICSC-8/Doc.3.3, p. 5
Author Information
Steven Worley and Doug Schuster, NCAR, Boulder, Colo.; E-mail: worley@ucar.edu;
Phillipe Bougeault and Baudouin Raoult, ECMWF, Reading, U.K.; and De Hui Chen and
Jiandong Dong, CMA, Beijing
Table 1. Summary of THORPEX Interactive Grand Global Ensemble (TIGGE) Data
Providers on 1 May 2008a
Number ofstandard
fields out of arecommended
set of 73
Number ofensemblemembers
Forecast
length (days)
Number of
forecasts per
day
a

BOM
55

CMAb
60

CMC
56

CPTEC
55

ECMWFb
70

JMA
61

KMA
46

MF
62

NCEP
59

UKMO
70

33

15

21

15

51

51

17

11

21

24

10

10

16

15

15

9

10

2.5

16

15

2

2

2

2

2

1

2

1

4

2

Abbreviations are BOM, Bureau of Meteorology Research Centre; CMA, China
Meteorological Administration; CMC, Centre Météorologique Canadien; CPTEC, Centro dePrevisão de Tempo e Estudos Climáticos; ECMWF, European Centre for Medium-Range
Weather Forecasts; JMA, Japan Meteorological Agency; KMA, Korea Meteorological
Administration; MF, Météo-France; NCEP, National Centers for Environmental Prediction;
UKMO, U.K. Met Office.
b
CMA and ECMWF perform dual roles as data providers and archive centers. NCAR,
not shown in the table, is exclusively an archive center.

CAS/ICSC-8/Doc.3.3, p. 6
ANNEX II
GIFS-TIGGE Working Group Meeting
Seventh meeting
1800, 15 September 2009, Driftwood 1, Portola Hotel, Monterey
MINUTES
Present: Zoltan Toth (NOAA), Richard Swinbank (UKMO), Ken Mylne (UKMO), Carole
Labadie (Meteo-France), David Monkam (Univ. Douala), Jim Caughey (WMO), David
Burridge (WMO), Dave Parsons (WMO), Olivier Talagrand (LMD/CNRS), Tom Hamill(NOAA), Kaustuha Bhattacharya (NCMRWF), Bian Xiaofeng (CMA), Jing Chen (CMA),
Tetsuo Nakazawa (JMA), Mio Matsueda (JMA), Laurie Wilson (EC), Tiziana Pacagnella(ARPA-SIM), Craig Bishop (NRL) Baudouin Raoult (ECMWF), Kamal Puri (BoM), David
Richardson (ECMWF), Peter Chen (WMO), Doug Schuster (NCAR)
1. Opening
RS welcomed everyone to the meeting. Given the limited time available this evening, RS
explained that we would not go through the detailed actions agreed at the previous working
group (WG) meeting, but we would instead limit the agenda to the highest priority items. We
plan to have a full meeting in a few months’ time where issues would be discussed at
greater length. Since several attendees were observers or were standing in for regular WG
members, all the meeting participants introduced themselves before proceeding with theformal agenda.
2. Publicising TIGGE
RS highlighted the importance of publicising TIGGE to both current and potential users of
the TIGGE archive data. A particular priority, to help researchers understand the TIGGE
data, is to ensure that the model descriptions that are available on the website are bothcomplete and up to date. He noted that a few centres had still not provided model
descriptions in the Excel format agreed previously by the WG.

Action 7.2.1: RS to send a further request to centres which have not provided descriptions in
the agreed format.
Action 7.2.2: All to provide updates to model descriptions after significant changes
It was suggested that we should publicise both research studies carried out using TIGGE
data, and information about ensemble forecasting techniques used by the TIGGE forecast
centres. RS noted that the TIGGE website carries a list of TIGGE-related publication,
though this is not necessarily up to date.

Action 7.2.3: All to send details of TIGGE-related papers to ECMWF for inclusion on thewebsite.
DB asked the working group to consider ourselves a group of scientists promoting ensemble
prediction, rather than just technical experts. RS said that the co-chairs would like todevelop the TIGGE website to include more information about the GIFS-TIGGE working
group and our meetings, and to include plans for GIFS as they develop. DR confirmed that
ECMWF are happy to continue hosting the TIGGE website.

Action 7.2.4: RS & ZT to liaise with DR over expanding material on the TIGGE website
Although the usage of the TIGGE data was thought to be higher than suggested by the raw
usage statistics of the TIGGE data, RS said that the WG needs to consider ways to publicise
TIGGE both nationally and regionally. DB asked the co-chairs to provide illustrations andwrite a one-page description to help publicise TIGGE at the GEO plenary. This flyer could
also be used for general promotion of TIGGE. DB suggested promoting TIGGE via national
Meteorological Societies, and volunteered IPO help.

Action 7.2.5: RS & ZT to provide TIGGE illustrations and write one-pager to help promote
TIGGE.

CAS/ICSC-8/Doc.3.3, p. 7
3. GIFS-FDP proposal
RS distributed copies of the latest draft (v4) of the proposal for a GIFS Forecasting
Demonstration Project. The aim of the project is to develop and evaluate products to help
forecast high-impact weather – specifically tropical cyclones and then heavy precipitation. It
is planned to engage with the operational community by initially running GIFS-FDP regional
subprojects in conjunction with the CBS Severe Weather Forecast Demonstration Project.
The current draft takes into account points raised during the WG teleconference that took
place on 10th July. Given that the briefness of this meeting, there would only be limited time
for discussion, but the co-chairs would welcome comments sent by email after the meeting.
DP commented that the project would be more appropriate as a WWRP research &demonstration project (RDP) than a forecast demonstration project (FDP). Verification
should be an important component – including user-oriented verification as well as
conventional verification statistics. It was noted that verification should be a key componentof evaluating products in an RDP. PC commented that, in practice, in was not possible to do
as much verification as intended in the Southern African SWFDP subproject. DB asked for
additional feedback to be sent to the co-chairs by the end of September, to allow a revised
version to be produced in good time for discussion at the ICSC-8.

Action 7.3.1: All to provide any additional comments to RS & ZT by end of September
ZT asked for volunteers to lead the two prototype product development groups. TN agreed
to lead the Tropical Cyclone group, probably in conjunction with a colleague from CMA (tobe nominated). KP suggested Beth Ebert would also be interested in co-leading the TC
group. Although no-one committed themselves to leading the precipitation group, LW said
he would consider this.
4. Proposed extended WG meeting
The next meeting of the GIFS-TIGGE WG is planned to be a joint meeting with WWRPTHORPEX and CBS/SWFDP experts. The main focus of the meeting would be
development of details plans for the GIFS-FDP. RS suggested meeting in Geneva inFebruary 2010; this would facilitate participation by WMO staff. It should also be possible tocoordinate the WG meeting with a planned meeting of the SWFDP Steering Group which isalso proposed for February. It was agreed that this would be a suitable time-frame.

Action 7.4.1: RS/ZT to finalise meeting dates, coordinating with planned SWFDP SG meeting.
5. Any Other Business
RS noted that the planned Shanghai EXPO project in Spring 2010 needs real-time access to
CXML cyclone track forecasts. There was general agreement that this should be expedited.

Action 7.5.1: All data providers requested to enable real-time access to real-time cyclone track
forecasts..

CAS/ICSC-8/Doc.3.3, p. 8

ANNEX III
GIFS Focus Group Meeting - Thursday 17th Sept 1530, Driftwood 1, Portola Hotel,
Monterey.
Present: Zoltan Toth (NOAA), Richard Swinbank (UKMO), Peter Chen (WMO), David
Richardson (ECMWF), David Monkam (Univ Douala), Tiziana Pacagnella (ARPA-SIM),
Stephane Vannitsem (RMI), John Gaynor (NOAA), Olivier Talagrand (LMD/CNRS),
Malaquias Peria (NOAA), Jing Chen (CMA), Tetsuo Nakazawa (JMA), Ken Mylne (UKMO),
Warren Tennant (UKMO), Carole Labadie (Meteo-France), Kaustubha Bhattacharya(NCMRWF), Baudouin Raoult (ECMWF), Andrea Montani (ARPA-SIMC), Craig Bishop(NRL), Warwick Norton (Cumulus), Jennifer Adams (COLA), Laurie Wilson (EC), Doug
Schuster (NCAR) and (via conference phone) Beth Ebert (BoM)
MINUTES
Zoltan Toth welcomed everyone to the meeting, and all introduced themselves. Beth Ebert
participated via the teleconference facility. A sign-up sheet was passed around the room,
allowing all to register an interest in taking part in either of the two focus groups.
Zoltan had prepared some slides. Although there were no facilities to show them in themeeting room, he used them to outline the proposed roles of the focus groups, principally toagree technical approaches for data exchange, product generation and statistical correction.
There was some discussion on how the groups should communicate with one another. It
was agreed that initially, email mailing lists would be best. Other methods, such as weblogs
may be adopted later. [Doug Schuster agreed afterwards to ask Unidata to host two focus
group mailing lists, since they already host the TIGGE users list.]
The role of the proposed focus groups are:1.

Data exchange; archiving; data policy; web interface; exchanging products

2.

Product algorithms; shared software tools; bias correction; standards; testing;
web interface for product display
There is some overlap between the groups; in response to a query to Baudouin, Zoltan said
that the essential distinction was that FG1 was IT-focused, while FG2 was mainly concernedwith algorithms.
The initial aim is to develop technical solutions in support of GIFS-RDP.
GIFS should use WIS (WMO Information System) protocols and guidelines. WIS catalogues
data using ISO standards. Whilst GTS is used just for exchanging operational data, both
GTS and Internet are valid ways to exchange data under WIS. The practicalities of data
access, and where products are calculated are to be resolved by the relevant members of
the focus groups.
Zoltan listed various groups, mainly US-based, who could potentially contribute to technicalwork for GIFS. Zoltan said he would like those groups to be engaged with GIFS, andperhaps join the focus groups. RMORPH and CMORPH links should be added to the TIGGE
website. Richard asked all to suggest similar groups in other countries who could be added
to the list.
Zoltan asked for (one or more) volunteers to coordinate each focus group. Baudouin Raoult
agreed to coordinate FG1. Lacking a volunteer, Richard suggested FG2, since it is moreproduct focused, could be coordinated by the product interest group leads. At the GIFSTIGGE WG, possible coordinators of the interest groups had been discussed. Nakazawasan had agreed to coordinate the tropical cyclones (with probably someone from CMA, andpossibly Beth Ebert). A coordinator for heavy precipitation has not yet been agreed(possibly Laurie?).
Meeting closed at 1625, in time for the symposium session.