3D-Var analysis system

W.-S. Wu&, M. Xue#, T. Schlatter@, R.J. Purser&, M. McAtee%, J. Gao#, D.

Devenyi@, J. Derber*, M. Pondeca*, D. Barker+, S. Benjamin@, R. Aune$

& General Sciences Corporation/SAIC and NOAA/NCEP/EMC, *NOAA/NCEP/EMC, % AFWA/The Aerospace Corporation,

# CAPS/OU, @ NOAA/FSL, + NCAR/MMM, $ NESDIS

Topics

• Review status and progress

• Release of Basic version

• NWS Risk reduction

• Future work

Basic System ComponentsNCAR (Completed, Underway, Not started)

• External iteration • Ensuring code runs on various machines• Include pseudo-obs for study of background error

structures• Convert 3DVAR from B- to A- grid• Bug fixes and code efficiencies• Parallel version• Additional variational diagnostics• WRF Grid I/O

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Number Of Processors

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ll C

lock

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MPP Control Variables+Obs Operators

+MPP Minimization

+Local Background

Perfect Scaling

3DVAR MPP Scalability – NCAR IBM-SP

•Test Study: 140x150x41 AFWA 45km “T4 theater” – 25th Jan 2002.

•Background error tuning – Old Its = 98, New = 49 (64PE = 58s).

Adaptive Tuning Of Observation/Background Errors

•Method follows Dezrosiers and Ivanov (2001):

•E(J) = p / 2, E(Jo)= ( p – Tr(HK) ) / 2, E(Jb)= Tr(KH) / 2

•Estimate Tr(KH) = ( O-1/2 )T ( H dx(yo + O1/2 ) - H dx(yo) )

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Total Jb

Adaptive Tuning Of Observation/Background Errors

•Method follows Dezrosiers and Ivanov (2001):

•E(J) = p / 2, E(Jo)= ( p – Tr(HK) ) / 2, E(Jb)= Tr(KH) / 2

•Estimate Tr(KH) = ( O-1/2 )T ( H dx(yo + O1/2 ) - H dx(yo) )

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or

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nin

g F

act

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synop u

synop v

synop t

synop p

synop q

Total Jb

Adaptive Tuning Of Observation/Background Errors

•Method follows Dezrosiers and Ivanov (2001):

•E(J) = p / 2, E(Jo)= ( p – Tr(HK) ) / 2, E(Jb)= Tr(KH) / 2

•Estimate Tr(KH) = ( O-1/2 )T ( H dx(yo + O1/2 ) - H dx(yo) )

Basic System ComponentsNCEP (Completed, Underway, Not started)

• Input of data from BUFR format• Stagger/unstagger grid interface• Bug fixes and code efficiencies• New (optional) background error covariance

formulation• Internal 3DVAR changes for WRF mass-core.

Basic System ComponentsAFWA (Completed, Underway, Not started)

• Use of original vertical coordinate for observations

• Comprehensive performance diagnostics

Basic System ComponentsFSL (Completed, Underway, Not started)

• Inclusion of Profiler data

• Conversion to i = x, k = 1 at bottom.

Basic System ComponentsCIMSS (Completed, Underway, Not started)

• Comprehensive documentation

Major Milestones

• Aug. 2002 (Oct. 2001) – Release of Basic version– Simple version with limited data, but basic structure of

more advanced versions

• June 2003 (Nov. 2002) – Release of Research version– Includes current state-of-the-art in data assimilation– Additional time (> 1 year) necessary to improve results.

• 2006 – Release of Advanced version– Includes additional data assimilation science developed

under auspices of WRF

Risk Reduction

• Modification of Eta analysis system to handle WRF I/O– Risk reduction for operational WRF system– Basis for comparison for research version of

WRF

Research version

• Situation dependent Background error covariances – NCEP/FSL

• Appropriate Balance constraints ( Jc ) - CAPS

• MPI/single processor, many machine capable – NCAR/NCEP

• Quality control• First Guess at Appropriate Time - NCAR

Research version

• Inclusion of additional observations– Radiances over ocean and above surface –

NCEP/FSL– Doppler winds and reflectivities – ground based

and aircraft – NCAR/CAPS– Scatterometer (NCAR).

Potential advanced version components

• Enhanced definition of background errors

• Model bias correction

• Additional analysis variables– Cloud/Precipitation– Ozone/aerosols/etc. – Land Surface (snow, soil moisture, soil

temperature, etc.)

Potential advanced version components

• Additional Observations– GPS radio-occultation/ground based– Satellite imagery/new sounders/over land, ice

and snow– cloud observations, – land surface observations, – etc.