page 1 validation by model assimilation and/or satellite intercomparison - esrin 9–13 december...

Validation by Model Assimilation and/or Satellite Intercomparison - ESRIN 9–13 December 2002

Monitoring of near-real-time SCIAMACHY, MIPAS, and GOMOS data at

ECMWF

Author: Antje Dethof (ECMWF)

ECMWF model

Operational ozone assimilation

Monitoring of Meteo products

- SCIAMACHY (SCI_RV__2P)

- MIPAS (MIP_NLE_2P)

Summary

Outline


Global spectral model (u,v,T,ps,q,o3,cc,cl,ci)

Resolution: - TL511 40 km (TL159)

- 60 levels up to 0.1 hPa ( 65 km)

Comprehensive physics package

Ozone is prognostic model variable

Data assimilation system: 12-hour 4D-Var (6-hour 3D-Var)

The ECMWF model


Operational ozone assimilation (4D-Var)• GOME (ERS2): - Total column ozone - NRT retrievals from KNMI (version FD 3.1) - approx. 20000 obs daily (14000 used)

• Blacklist criteria: - at solar elevations < 10° - at latitudes > 40° in NH - at latitudes < -50° in SH - QC flag > 0

• SBUV/2 (NESDIS retrievals): - NOAA-16 - NOAA-14 passive - NOAA-17 passive (since 20020804,18z)

- 6 ozone layers: 0.1-1 hPa, 1-2 hPa, 2-4 hPa, 4-8 hPa, 8-16 hPa, 16hPa – surface

- approx. 1400 obs daily (1200 used)

• Blacklist criteria: - at solar elevations < 6° - QC flag > 0


Passive assimilation: Data are not assimilated actively, but go through the assimilation system and statistics (e.g. first-guess departures) are calculated

Use assimilation system to evaluate data quality, biases, instrument and algorithm stability (can also show model problems)

Output statistics:

- Number of data

- Mean

- Stdev of

Monitoring

Observations

Departures (first-guess, analysis)


Meteo products from ftp-ops.pdk.envisat.esa.int, converted into BUFR format at ECMWF

SCIAMACHY ozone data about 25 DU lower than KNMI GOME data in tropics and mid-latitudes

Unrealistically large values at high latitudes

Unrealistically low values at high southern latitudes that were seen earlier have disappeared

No geolocation information (e.g. sza, fov) in Meteo data

Monitoring of SCIAMACHY Meteo data (SCI_RV__2P) Ozone


SCIAMACHY total column ozone: 18.-24.11.2002

SCIAMACHY GOME (KNMI)


SCIAMACHY total column ozone: 18.-24.11.2002SCIAMACHY GOME (KNMI)

Observation values

Fg departures

Unrealistically

large values

25 DU


Good agreement of MIPAS temperatures with ECMWF analyzed temperatures over large part of stratosphere (diff < 2%)

Largest differences at 0.1 hPa (ECMWF model top)

MIPAS temperatures too low at bottom end of profiles

(cloud contamination ?)

Upgrade on 13.11.2002, 12z:

Reduced fg-departures (MIPAS – ECMWF) below 60-80 hPa

Increased number of profiles extending below 100 hPa

Cooling above 1 hPa between 65-90S

Monitoring of MIPAS Meteo data (MIP_NLE_2P)Temperature


4.-10.11.02 11.-17.11.02

DeparturesMIPAS - EC

Improvement after 13.11.02

MIPAS

ECMWF

T profiles – global averages


Temperature (zonal means at 100 hPa): 11.-17.11.2002

More data at 100 hPa after 13.11.2002

11.11.

17.11.

Time

MIPAS


Reasonable agreement with ECMWF ozone over large part

of stratosphere Some differences might be explained by known ECMWF model bias: e.g. – tropical O3 max. lower in ECMWF than MIPAS

- 90-65ºN: ECMWF > MIPAS over large part of stratosphere

Unrealistically large MIPAS ozone values in lower stratosphere (cloud contamination ?)

Upgrade on 13.11.2002, 12z: Reduced departures (MIPAS – ECMWF) in lower stratosphere Reduced number of unrealistically large MIPAS ozone values, but some large values remain

MIPAS Ozone


Ozone profiles: 0 – 20ºS

MIPAS

ECMWF

Improvement after 13.11.02

11.-17.11.024.-10.11.02


Ozone scatter plot (4.-10.11.02): 100-150 hPa

Unrealistically large

values in tropics


MIPAS water vapour values generally larger than ECMWF

values (sign in agreement with known dry bias of ECMWF analyses in stratosphere) Unrealistically large MIPAS water vapour values at bottom end of profiles (cloud contamination ?)

Upgrade on 13.11.2002, 12z: Reduced MIPAS water vapour values between 20-100 hPa Fewer unrealistically large water vapour values at bottom end of profiles, but some large values remain

MIPAS - Water Vapour


Water vapour profiles: 0-20ºS (11.-17.11.02)

MIPAS

ECMWF

Dry bias of ECMWF Cloud contamination of MIPAS?

11.11. 17.11.

Time

Zonal mean MIPAS (60-80 hPa)

Change on 13.11.02


Monitoring of Meteo products at ECMWF

SCIAMACHY: Values ca. 10% lower than ECMWF or GOME (KNMI) over large parts of globe

MIPAS: Profile values seem reasonable, possible cloud contamination at bottom of profiles

GOMOS: Worse data quality than MIPAS. Large scatter. Water vapour values unrealistically large.

Continuation of monitoring

Experimental assimilation of ENVISAT data

Please add geolocation information to L2 products

Summary and Outlook

page 1 validation by model assimilation and/or satellite intercomparison - esrin 9–13 december...

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