A New 4D Variational Data Analysis Scheme in the Framework of VERA
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Transcript of A New 4D Variational Data Analysis Scheme in the Framework of VERA
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Wolfgang Gepp ICAM 2003
A New 4D Variational Data Analysis Scheme in the Framework of VERA
University of Vienna Department of Meteorology
and Geophysics
Wolfgang Gepp
Department of Meteorology and Geophysics, University of Vienna
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Wolfgang Gepp ICAM 2003
University of Vienna Department of Meteorology
and Geophysics
concept of VERA
interpolation of irregularly distributed data to a regular grid
data quality control (error correction)
a priori knowledge of small scale physical processes(Fingerprints)
variational algorithm using a form of thin plate splines
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Wolfgang Gepp ICAM 2003
University of Vienna Department of Meteorology
and Geophysics
„old“ VERA
already in operational use
valuable analysis and nowcasting tool
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Wolfgang Gepp ICAM 2003
University of Vienna Department of Meteorology
and Geophysics
Problems with „old“ VERA
restricted to 2D
insufficencies
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Wolfgang Gepp ICAM 2003
University of Vienna Department of Meteorology
and Geophysics
we want
more reliable results
avoid insufficencies
include vertical sounding data
analyse 3D phenomena
temporal extrapolation
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Wolfgang Gepp ICAM 2003
University of Vienna Department of Meteorology
and Geophysics
extend
algorithm to 3D and 4D
VERAXX
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Wolfgang Gepp ICAM 2003
University of Vienna Department of Meteorology
and Geophysics
why a new scheme?
old algorithm becomes expensive for 4D
keep algorithm simple
for usual commercial PC platforms
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Wolfgang Gepp ICAM 2003
University of Vienna Department of Meteorology
and Geophysics
VERAVERAXX
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Wolfgang Gepp ICAM 2003
University of Vienna Department of Meteorology
and Geophysics
10x10x10x10
10000 gridpoints
10000 equations
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Wolfgang Gepp ICAM 2003
University of Vienna Department of Meteorology
and Geophysics
solution
Partial Grid Calculation
5x5x5x5 subdomain
max. 625 equations
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Wolfgang Gepp ICAM 2003
University of Vienna Department of Meteorology
and Geophysics
Partial Grid Computation
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Wolfgang Gepp ICAM 2003
University of Vienna Department of Meteorology
and Geophysics
how get data into calculation?
VERA
VERAXX
pentagons out of stations
stations usually not at gridpoints
derive gridpoint values from stations
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Wolfgang Gepp ICAM 2003
University of Vienna Department of Meteorology
and Geophysics
Deriving Grid Point Values
A
4 3
1 2
dx
dy
4321 )1()1()1)(1( yxyxxyyxA
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Wolfgang Gepp ICAM 2003
University of Vienna Department of Meteorology
and Geophysics
First VERAXX results
only 3D calculations so far
no Fingerprints used
error correction from VERA
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Wolfgang Gepp ICAM 2003
University of Vienna Department of Meteorology
and Geophysics
Horizontal Cross Section
H=220m
Zell am See, 15. Nov. 2002, 1800 UTC
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Wolfgang Gepp ICAM 2003
University of Vienna Department of Meteorology
and Geophysics
Vertical Cross Section
Zell am See, 15. Nov. 2002, 1800 UTC
S N
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Wolfgang Gepp ICAM 2003
University of Vienna Department of Meteorology
and Geophysics
More Information?
http://www.univie.ac.at/img-wien/vera
http://www.alpenwetter.net