Assimilation of EOS Aura Ozone Data for NWP and Air Quality Applications

1
Assimilation of EOS Aura Ozone Data for NWP and
Air Quality Applications

• I. Stajner and L.-P. Chang
• GMAO NASA Goddard and SAIC

JCSDA Science Workshop Greenbelt,
Maryland, June1, 2006
2
GEOS-5

• GMAO model coupled to GSI
• Allows full ozone feedbacks
• GSI-model interface through Incremental Analysis
  Update
• GMI chemistry module (troposphere and
  stratosphere) will be implemented

3
Goals

• Assimilation of Aura OMI and MLS ozone data in
  GEOS-5 using GSI
• Stratospheric ozone will be constrained by MLS
  data OMI and the model will provide tropospheric
  ozone columns and profiles
• Investigate impacts of Aura ozone on NWP through
  heating rates and assimilation of radiances from
  nadir infrared sounders (e.g. AIRS)
• Evaluate the quality of tropospheric ozone by
  comparison with high quality independent data

4
Background

• Impact of Aura OMI and MLS data on ozone in
  GEOS-4
• Spatial and temporal variability of ozone needs
  to be captured in order to get improvements from
  ozone feedback

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Impact of Aura data
Zonal mean of Aura assimilation-minus-model
(color, ) and assimilation (contours, ppmv) on
20050312
0.1
1

• Stratosphere
• Increase in lower stratosphere
• Decrease near the tropopause ? stronger vertical
  gradient
• Fix leaky pipe
• Decrease near poles at 15hPa

Pressure (hPa)
10
100
975
90S
90N
Troposphere Decrease at high latitudes and
northern middle latitudes
Increase in southern Tropics and middle latitudes
GEOS-4
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Ozone variability
MLSOMI assimilation at 100 hPa on January 9, 2005

• Intrusion of low ozone air at 100 hPa from the
  Tropics is advected eastward and wrapped around
  higher ozone over Canada. Circles mark locations
  where SAGE III ozone was less than 10 mPa on the
  previous day at sunset.

January 11, 2005
January 12, 2005
Collocated SAGE III and Aura assimilated profiles
SAGE III Aura assim.

• Spatio-temporal variability of lower
  stratospheric ozone is well represented in Aura
  assimilation into GEOS-4.

January 13, 2005
0
180W
4 5 6 7 8 9 10 11 12 13 14
15 mPa
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OMI in GEOS-5

• Cycling assimilation runs for September 2004
• OMI cloud-free data (reflectivity lt15) were
  assimilated in GSI using the code developed at
  NCEP
• Version 8 retrievals of NOAA-16 and NOAA-17
  SBUV/2 data were assimilated (as for MERRA)
• AIRS channels 1003-1285 were not used
• HIRS channels 5 and 9 were assimilated for
  NOAA-14 and NOAA-17
• Impact seen at small spatial scales, but changes
  in zonal mean ozone are not large (in GEOS-5 with
  intermittent analysis updates)

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Case study impacts of ozone data

• In order to separate impacts of different data
  types on ozone in GSI these data types were
  turned off sequentially
• Comparisons for a single synoptic time (0z on
  September 6, 2004) will be shown

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OMI O-F residuals at 100 hPa

• Typical coverage of OMI data for reflectivity
  lt15 for one synoptic time (0z on September 6,
  2004)

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Ozone analysis increments at 100 hPa

• OMI on
• SBUV, HIRS, AIRS off

• AIRS on (1003-1285 off)
• SBUV, HIRS, OMI off

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Ozone analysis increments at the Equator
0.2
1
MLS data will be assimilated
Pressure (hPa)
10
100
1000
120E
120W
-2 0 2 4 6 8 10 12 14 16 18

• OMI on
• SBUV, HIRS, AIRS off

• AIRS on (1003-1285 off)
• SBUV, HIRS, OMI off

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Conclusions and plans

• Preliminary evaluation of the impact of OMI data
  in the GEOS-5 (with Version 8 of N16 and N17
  SBUV, TOVS and AIRS data in GSI) done.
• GEOS-5 system rapidly maturing
• assimilated ozone can be used in radiation
• Incremental Analysis Update in order to improve
  transport of chemical constituents
• Plan further evaluation of impacts of OMI and
  comparisons with the impacts of AIRS
• Plan assimilation of MLS in GSI