TIGGE Implementation Meeting - Report
ECMWF 9-10 November 2005

9-10 November 2005

Slide 1ECMWF

Participantsz

Richard Swinbank richard.swinbank@metoffice.gov.uk

zSimon Thompson simon.thompson@metoffice.gov.ukz

Tan Le t.le@bom.gov.auz

Peiliang Shi shipl@cma.gov.cnz

Jean Nicolau jean.nicolau@meteo.frzWaldenio Almeida gambi@cptec.inpe.brz

Yves Pelletier yves.pelletier@ec.gc.caz

David Burridge d.m.burridge@btinternet.comz

Horst Boettger horst.boettger@ecmwf.intz

Baudouin Raoult baudouin.raoult@ecmwf.intzManuel Fuentes manuel.fuentes@ecmwf.int

zDavid Richardson david.richardson@ecmwf.intzWalter Zwieflhofer walter.zwieflhofer@ecmwf.intzPhilippe Bougeault philippe.bougeault@ecmwf.int

9-10 November 2005

Slide 2

ECMWF

Overviewz 1st TIGGE Workshop was held at ECMWF 1-3 March2005 (report available from www.wmo.int/thorpex)z Working Group on archiving (representatives fromthe three archive centres - CMA, ECMWF, NCAR)
met at ECMWF 19-21 September 2005 (report andsummary slides available from ECMWF)z Implementation Meeting at ECMWF 9-10 November

2005 held to address technical issues raised by thetwo preceding meetings. Participants from archivecentres and data providersz These slides constitute the report of thisimplementation meeting
9-10 November 2005

Slide 3

ECMWF

Definition of TIGGE databasez List of products
Î Reviewed the list of products (parameters, levels, steps) fromthe March Workshop
Î Data Providers (those present) agreed that they would aim tosupply these products to the Archive Centres. This would
require changes in the post-processing by the Data Providers.
Noting possible operational constraints, it was understoodthat there may be omissions from the list
Î No core dataset (compulsory list) was defined since enoughoverlap will exist between Data Providers

9-10 November 2005

Slide 4ECMWFDefinition of TIGGE databasez The following details were agreed:Î All accumulations to start from the beginning of the forecast
Î Geopotential Height to be used rather than Geopotential
Î Temperature extremes (max/min) to be provided over 6 hourintervals
Î Specific humidity to be provided in the free atmosphereÎ “2 metre temperature” to be used to refer to near surface

temperature parametersÎ All fields to use units as defined in GRIB Edition 2
Î Orography and Land-sea mask to be provided for the Control

for each output time-step. CMC to check whether this meetsthe requirement for their system. Orography to be provided as
geopotential height.
9-10 November 2005

Slide 5ECMWFList of products: single level
Parameter

Level

Unit

Output frequency

Comment

Mean sea level pressure

MSLPa6h

instantaneous

Surface Pressuresurface

Pa6h

inst

10m U-velocity

10mm s**-16h

inst

10m V-velocity

10mm s**-16h

inst

2m temperature

2mK

6h

inst

2m dew point temperature

2mK

6h

inst

2m max temperature

2m

K

6h

6_h

2m min temperature

2m

K

6h

6_h

Total precipitation (liquid + frozen)

surfacem6h

acc_stSnow fallsurfacem of water equivalent6hacc_stSnow depth

surfacem of water equivalent

6h

inst

z 6_h: accumulated over previous 6 hours
z acc_st: accumulated from start of forecast

9-10 November 2005

Slide 6ECMWFList of products: single level fields
ParameterLevelUnit

Output frequency

Comment

Total cloud coversurface0-100%

6h

instantaneous

Total column water

surfacekg m**-26h

inst

Surface latent heat flux

surfaceW m**-2 s6h

acc_stSurface sensible heat flux

surfaceW m**-2 s

6h

acc_stSurface solar radiation

surfaceW m**-2 s

6h

acc_stSurface thermal radiation

surfaceW m**-2 s6h

acc_stSunshine duration

surfaces6h

acc_stConvective available potential
energysurfaceJ kg**-16h

inst

Orography (Geopotential
height at the surface)surfaceminst

Land-sea masksurface0-1

inst

z acc_st: accumulated from start of forecastz Orography and Land-sea mask to be provided for

the Control for each output step
9-10 November 2005

Slide 7ECMWFList of products: upper air fields
Parameter

Unit

Output frequency

Comments

TemperatureK6hinstantaneous

Geopotential height

m6h

inst

U-velocity

m s**-16h

inst

V-velocity

m s**-1

6h

inst

Specific Humidity

kg kg**-1

6h

inst

z 5 parameters on 9 pressure levels, i.e. 45 fields.
z The 9 levels are 1000, 925, 850, 700, 600, 500, 300,

250 and 200 hPa.

9-10 November 2005

Slide 8ECMWFDefinition of TIGGE database: remaining
issues to be addressed by GIFS/TIGGE WG
z Products defining the initial conditions to evaluate
the various perturbation systems (more levels).
This may eventually require additional data out to48 hours
z Requirement for 3-hourly post-processing for alimited number of parameters for e.g. hydrologicalstudies. Operational constraints may make thisdifficult to implement, especially for the full rangeof the forecastz Investigation of the requirements for additional sea-ice, land snow/ice and soil parameters

9-10 November 2005

Slide 9ECMWFDefinition of TIGGE database (homogeneity)z Common terminology: naming of products
Î Agree to use the same names (implications for existingapplications)Î To be used for cataloguing and searching and requesting data
Î Aliases to be used to accommodate differences in local

naming conventions

9-10 November 2005

Slide 10ECMWFDefinition of TIGGE database (homogeneity)z Common data format
Î Agree to use the same format: GRIB Edition 2
Î Preserve native grids and resolutions
Î Data Providers to supply interpolation routines for conversion

to regular lat-lon grids and for point extraction
Î Archive Centres to specify interfaces for interpolation routines
Î Archive Centres may endeavour to return data in regular grids

using these interpolation routines

9-10 November 2005

Slide 11ECMWFTechnical aspects of data exchangez Data flowÎ NCAR to complete study of IDD/LDM, including security

requirements. IDD/LDM has all the tools that are required forTIGGE, ie, statistics, monitoring, re-transmission, network
checksumÎ BoM noted different costs for pushing vs pulling.

9-10 November 2005

Slide 12

ECMWF

Data formats: GRIB2 issues
z Proposals to WMO expert team on codes:
Î Missing TIGGE parameters
Î Support for checksum
Î New production status of data: THORPEX or TIGGE
Î Some Centres may require additions for encoding their nativegrids

z If GRIB2 cannot accommodate all TIGGE

requirements, eg checksum, a TIGGE local
extension (section 2) understood by all partners
may be needed.

9-10 November 2005

Slide 13

ECMWF

Data Formats: GRIB2 issues
z Noted the need for a version of the data for testingpurposes (0001 for production data)z Guidelines on GRIB 2 usage (best practise) toensure common coding will be drafted andcirculated for comments

9-10 November 2005

Slide 14ECMWF

File structurez Agreed on the proposed file structure and naming

convention
z Archive Centres will use the file structure tovalidate the contents of the filez Propose to WMO expert group to change theextension to .grib2 instead of .bin

9-10 November 2005

Slide 15

ECMWFOrganisation of data exchangez Completeness of dataÎ Missing data is unavoidable. Dummy fields will not bearchived instead.
Î Data will be considered late after 24 hours (timeliness).

Archive Centres will take action to investigate missing data.

z Procedures and control mechanisms
Î Agreed that Archive Centres are technical coordinators
Î ECMWF offered to host a Website and mailing lists
Î All TIGGE Data Providers and Archive Centres to nominate

contact points

9-10 November 2005

Slide 16ECMWF

User access: Registrationz Data Providers to supply their products to theArchive Centres under an agreed set of rules, which
will include re-distribution rights
z Access to be provided for Research & Education

through a simple electronic registration process,with valid e-mail address and acknowledgment ofconditions of supply
z Under the simple registration process, access to begiven with a delay (48 hours) after initial time of theforecast (reference time of data in GRIB2)z Registration for real-time access to be handled via

the THORPEX IPO
9-10 November 2005

Slide 17ECMWF

User access: Data retrieval
z It is unavoidable that in Phase 1 each Archive

Centre will provide data through a different userinterface
z Feedback is required to check if the field orderproposed is sufficient to meet most user
requirements

9-10 November 2005

Slide 18

ECMWF

Implementation plan : Data transportz Test transfer rates between Archive Centres: NCAR,ECMWF and CMA. Find best buffer sizes.
z Investigate other candidates for data transport:

IDD/LDM, AFD, sftp
z Test transfer rates between Data Providers (e.g.

CMC) and Archive Centres: NCAR, ECMWF andCMA.
z Results of these tests to be provided on the TIGGE

Website9-10 November 2005

Slide 19

ECMWF

Implementation plan : GRIB2z ECMWF to consult with NAEFS and WMO Expert

Team on Data Representation and Codes (ET-DRC)
to make sure that there is agreement on the proper
encoding of the fields in GRIB2z ECMWF to provide sample model output to the DataProvidersz ECMWF to provide a series of example programs tocreate these files
Î These tools may have to be adapted by Data Providers inorder to handle their own data and metadata mapping

9-10 November 2005

Slide 20

ECMWF

Implementation planz Establish archive management communications:Î Mailing lists, web sites and collaborative tools
Î Collect list of contact points from Data Providers and ArchiveCentresz Start filling the TIGGE database with data fromparticipating Data Providers after initiating the dataexchange through the THORPEX IPO

9-10 November 2005

Slide 21

ECMWF