1

Observing Systems Observing Systems

ERA-40 ExperienceERA-40 Experience

Sakari Uppala & ERA TeamSakari Uppala & ERA Team

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1957 2001TOMS/ SBUVTOMS/ SBUV1979

METEOSAT METEOSAT ReprocessedReprocessed

1982 1988

VTPRVTPR1973 1979

TOVS:TOVS:HIRS/ MSU/ SSUHIRS/ MSU/ SSU

CMWCMW

1987SSM/ISSM/I 1991

ERS-1ERS-11995ERS-2ERS-2

1998ATOVSATOVS

CONVENTIONAL SURFACE, UPPERAIR AND AIRCRAFT DATANCAR/ NCEP, ECMWF, JMA, US Navy, Twerle, Gate, FGGE, TOGA, TAO, COADS, …

OBSERVING SYSTEMS IN ERA-40OBSERVING SYSTEMS IN ERA-40

3

Combining the different conventional Combining the different conventional data sourcesdata sources

CONVENTIONAL SURFACE, UPPERAIR AND AIRCRAFT DATANCAR/ NCEP, ECMWF, JMA, US Navy, Twerle, Gate, FGGE, TOGA, TAO, COADS, …

CONVENTIONAL SURFACE, UPPERAIR AND AIRCRAFT DATANCAR/ NCEP, ECMWF, JMA, US Navy, Twerle, Gate, FGGE, TOGA, TAO, COADS, …

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Illustration

The number of available TEMP/ land data per year from different data sources at 00UTC Navyraob

US AirforceNCEP TD54NCEP TD52NCEP ON29NCEP ON20NCEP Upperair

NCAR/NCEP CollectionJMA OperationalECMWF Operational

TOGAFGGETWERLGATE

MiscellaneousFranceChinaRussiaCountriesUS Control

Australian Antartic

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Illustration

The number of available TEMP/ land data per year from different data sources at 00UTC Navyraob

US AirforceNCEP TD54NCEP TD52NCEP ON29NCEP ON20NCEP Upperair

NCAR/NCEP CollectionJMA OperationalECMWF Operational

TOGAFGGETWERLGATE

MiscellaneousFranceChinaRussiaCountriesUS Control

Australian Antartic

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ILLUSTRATION: THE IMPORTANCE OF MERGE

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Radiosonde temperature bias, OB-FGRadiosonde temperature bias, OB-FG(4 solar elevation angle intervals and the mean) (4 solar elevation angle intervals and the mean)

all year 1994, South West Canadaall year 1994, South West Canada

UncorrectedUncorrected

CorrectedCorrected

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ERA-40: SYNOP-Ps 00 UTC Southern hemisphere RMS (hPa) OB-FG OB-AN 15 days MA

Number of used observations per day

ERA-40: SYNOP-Ps 00 UTC Northern hemisphere RMS (hPa) OB-FG OB-AN 15 days MA

Number of used observations per day

2 hPa

2 hPa

1000

1000

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ERA-40: TEMP-T 500 hPa 00 UTC Northern hemisphere RMS (K) OB-FG OB-AN 15 days MA

Number of used observations per day

1K

ERA-40: TEMP-T 500 hPa 00 UTC Southern hemisphere RMS (K) OB-FG OB-AN 15 days MA

Number of used observations per day

1K

Problem with elimination of duplicates

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ERA-40: TEMP-T 50 hPa 00 UTC Northern hemisphere RMS (K) OB-FG OB-AN 15 days MA

Number of used observations per day

ERA-40: TEMP-T 50 hPa 00 UTC Southern hemisphere RMS (K) OB-FG OB-AN 15 days MA

Number of used observations per day

2K

2K

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ERA-40: TEMP-Q 850 hPa 00 UTC Tropics RMS (g/kg) OB-FG OB-AN 15 days MA

Number of used observations per day

HumidityConversion Problem

Datasource: MIT

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Snow data coverage (sdepth>0)

19581958 1966

1976 1986

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Conventional ObservationsConventional Observations

Identify and fill the missing data inIdentify and fill the missing data inpriority orderpriority order

Improve the merging/ screeningImprove the merging/ screeningprocessprocess

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Satellite Radiance DataSatellite Radiance Data

TOVS HIRS/ MSU/ SSUTOVS HIRS/ MSU/ SSU

ATOVS AMSU-A, AMSU-BATOVS AMSU-A, AMSU-B

VTPRVTPR

SSM/ ISSM/ I

Datasets relatively completeDatasets relatively complete

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14 NOAA Satellites14 NOAA Satellites

TOVS / ATOVSVTPR

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(John Bates, Darren Jackson)(John Bates, Darren Jackson)

1978 1998 1978 1998

MSU Channel 3 MSU Channel 4

NASA Langley Research CenterNASA Langley Research CenterRadiation and Aerosols BranchRadiation and Aerosols Branch

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Pinatubo

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NOAA-11 SSU NOAA-14 SSU

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10 hPa

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Average 30 hPa Geopotential, November - December 1972

Mean & STD of 30 hPa Geopotential Increment, November - December 1972

VTPR Active

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ERA-40: TEMP U-Wind 50 hPa 00 UTC Northern Hemisphere RMS (m/s) OB-FG OB-AN 15 days MA

ERA-40: TEMP U-Wind 50 hPa 00 UTC Southern Hemisphere RMS (m/s) OB-FG OB-AN 15 days MA

Number of used observations per day

Number of used observations per day

NOAA-15AMSU-A, HIRS

HIRS BL CH-14/ AMSU-A BL

NOAA-11HIRS/MSU/SSU

NOAA-14 HIRS/MSU/SSU CH-2/ SSU BL

1 SSU Instrument

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ERA-40: SSMI/TCWV 00 UTC Tropics RMS (kg/m**2) OB-FG OB-AN 15 days MA

6

4

2

500

Number of used observations per day

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Aspects relating the use of radiancesAspects relating the use of radiances

Problem periods per channel into “blacklist”Problem periods per channel into “blacklist”

Bias tuning necessaryBias tuning necessary

Overlapping periods importantOverlapping periods important

Cloud detectionCloud detection

Contamination by aerosolsContamination by aerosols

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Cloud Motion WindsCloud Motion Winds

Reprocessing improves the quality of analysesReprocessing improves the quality of analyses

25

METEOSAT Reprocessed Winds METEOSAT Reprocessed Winds

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ERA-40: SATOB U- Wind 850 00 UTC Tropics RMS (m/s) OB-FG OB-AN 15 days MA

Number of used observations per day

MeteosatReprocessed winds

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Differences in 10m wind speedDifferences in 10m wind speed

Contour interval 0.5ms-1

Yellow/red indicates ERA-40 winds stronger than ERA-15 winds

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Research based on reanalysesResearch based on reanalyses

Understanding & Understanding & ImprovingImproving

Observation datasets:Observation datasets:SatelliteSatellite

ConventionalConventional

Data Assimilation Data Assimilation SystemSystem

DevelopmentDevelopment

Improved use of Observing SystemsImproved use of Observing Systemsin the next reanalysisin the next reanalysis

FEEDBACKFEEDBACKINFORMATION:INFORMATION:

Observed valuesObserved valuesOB – FGOB – FGOB – ANOB – AN

FlagsFlags

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Research based on reanalysesResearch based on reanalyses

Understanding & Understanding & ImprovingImproving

Observation datasets:Observation datasets:SatelliteSatellite

ConventionalConventional

Data Assimilation Data Assimilation SystemSystem

DevelopmentDevelopment

Improved use of Observing SystemsImproved use of Observing Systemsin the next reanalysisin the next reanalysis

Need to Need to Create & Improve:Create & Improve:

User InterfacesUser InterfacesModern tools toModern tools to

visualizevisualize

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Check/ Modify Station height and position information

Detailed inventories of the merged dataset and data sources

Filling the possible gaps in time and space with additional data

Insert the new data into Data Base

Merge of observations and observed values:in the Screening step before minimization

Use the merged observations in reanalysis(n+1)

Investigate the Feedback information (Ob-Fg, Ob-An) :Statistics and time series per area/ station

Statistics of accepted/ rejected data per data source