1 The GEMS production systems and retrospective reanalysis Adrian Simmons.

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The GEMS production systems and retrospective reanalysis

Adrian Simmons

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• ERA-40

• ENVISAT cal/val and assimilation experience

• Development of analysis of CO2 from AIRS radiances

• Development of fast RT models

• Other developments of the ECMWF forecasting system

GEMS production systems and reanalysis will build on several ECMWF activities, including:

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• A reanalysis from September 1957 to August 2002

• Based on cycle 23r4 of ECMWF forecasting system- operational from June 2001 to January 2002

• Six-hourly 3D-Var analysis- operations uses 12-hourly 4D-Var

• T159 horizontal resolution (~125km grid)- operations uses T511 (~39km grid)

• Uses full 60-level resolution

The ERA-40 data assimilation system

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Trend and variability in two-metre temperature over land

CRUTEM2v from Jones and Moberg (2003)CRUTEM2v from Jones and Moberg (2003)

Linear trend: CRUTEM2v 0.171OC/decade

ERA-40 0.169OC/decade

ERA-40

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Linear trend in two-metre temperature (OC/decade)

CRUTEM2v from Jones and Moberg (2003)ERA-40

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Trend and variability in lower stratospheric temperature

Linear trend: MSU-4 - 0.39OC/decade

ERA-40 - 0.30OC/decade

NCEP - 0.82OC/decade

MSU-4 data analyzed by Mears et al. (2003)ERA-40 equivalent from Ben Santer, PCMDI

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Total ozone (following Pascal Simon, Météo-France)

Blue: ERA-40 (TOMS and SBUV data assimilated 1979-1988 and

1991-2002)

Red: Ground-based

measurements (NOAA/CMDL)

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Equatorial specific humidity

Model simulation

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100

1

hPa

One year

ERA-40

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100

1

hPa

One year

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Humidity and rainfall over the tropical oceans

Year

ERA-40

24 - 36h forecast

24h forecast

SSM/I retrievals from Remote Sensing Systems

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• ERA-40 production system was based on ECMWF’s prepIFS software for preparing and managing experimentation with its forecasting system

• prepIFS is available to Member-State users of the ECMWF forecasting system

• ERA-40 system was used remotely by Reading University and KNMI for studies of data denial

• Updated system will be available to GEMS partners

• GEMS funding will enable ECMWF to provide better support for external users than possible for ERA-40

Remote use of data assimilation system

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• An interim reanalysis- Start next year, T159L60 (L91?), latest version of forecasting system

- Run from 1991 (tbd) onwards, continued in close to real time

- Basis for future developments (including GEMS)

• Experimentation- To validate new versions of forecasting system

- High-resolution 4D-Var analyses for specific cases

- Observing system experiments

• Development of observational data base and processing software

• An extensive new reanalysis in 2008 or beyond

Reanalysis plans beyond ERA-40

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TOMS

With MIPAS

No MIPAS

Total ozone 1 October 2003

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26 Aug 2003 11 Sept 2003 22 Sept 2003

Sonde With MIPAS No MIPAS

Ozone profiles at Neumayer (71S, 8W)

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With MIPAS

No MIPAS

ECMWFTOMS

Ozone in the tropics 1 August 2003

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CO2 assimilation from AIRS - Stratosphere

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Monthly mean distribution for May 2003 is shown on the left, and the upper boundary for the error estimate is shown on the right.

CO2 assimilation from AIRS - Troposphere

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• Standard RTTOV software has been adapted to

include variable CO2

• RTIASI has been extended to include variable CO2,

CH4, N2O and CO; work on aerosols is planned

• RTTOV is being developed to handle limb-sounded

radiances from MIPAS (as part of development for a

capability for direct assimilation of these radiances)

Fast RT code development

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• 91-level model with improved resolution of tropopause and stratopause/mesosphere, plus work on gravity-wave parametrization and treatment of biases in data assimilation – to address stratospheric problems

• Work on humidity analysis, assimilation of rain-affected microwave radiances – to reduce spin-down

• Model has been extended to handle extra fields

• Work to extend Jb is planned for 2004

• Work on parametrization of convection and vertical diffusion to enable tracer transfer is planned for 2004

Forecasting-system development