Download - Assimilation of OMI Data Into NCEP’s GFS
![Page 1: Assimilation of OMI Data Into NCEP’s GFS](https://reader033.vdocuments.site/reader033/viewer/2022061410/56814e67550346895dbc04cb/html5/thumbnails/1.jpg)
Assimilation of OMI Data Into NCEP’s GFS
Craig Long,
S. Zhou, T. Beck, A.J. MillerNOAA/NWS/NCEP/Climate Prediction Center
L.Flynn
NOAA/NESDIS/STAR
![Page 2: Assimilation of OMI Data Into NCEP’s GFS](https://reader033.vdocuments.site/reader033/viewer/2022061410/56814e67550346895dbc04cb/html5/thumbnails/2.jpg)
Outline
Background Improvements due to OMI coverage OMI Issues Comparisons between SSI and GSI How OMI data is assimilated
Thinning possibilities
Summary What’s Next
![Page 3: Assimilation of OMI Data Into NCEP’s GFS](https://reader033.vdocuments.site/reader033/viewer/2022061410/56814e67550346895dbc04cb/html5/thumbnails/3.jpg)
Aspects of Ozone in NWP
Three aspects of dealing with ozone in NWP Assimilation of ozone observations
• Horizontal and vertical
• Agreement between multiple sources
Transport of ozone once in the model• Brewer Dobson Circulation
Ozone Chemistry• Homogeneous: Production and Loss
– f: Latitude, Pressure, Season
• Heterogeneous: 'Ozone Hole' type depletion
– Need additional observations
![Page 4: Assimilation of OMI Data Into NCEP’s GFS](https://reader033.vdocuments.site/reader033/viewer/2022061410/56814e67550346895dbc04cb/html5/thumbnails/4.jpg)
Background
Currently NCEP GFS assimilates SBUV/2 total and profile ozone measurements from both NOAA-16 and 17.
SBUV/2 provides about 90 nadir observations per orbit. Replacement instrument is the OMPS (Ozone Mapping
and Profiler Suite) Combination of scanning mapper and limb profile On NPP and NPOESS Will provide higher vertical and horizontal resolution
Current additional sources of ozone data available: Aura: OMI*, HIRDLS*, MLS, TES *NRT MetOp: GOME2*
![Page 5: Assimilation of OMI Data Into NCEP’s GFS](https://reader033.vdocuments.site/reader033/viewer/2022061410/56814e67550346895dbc04cb/html5/thumbnails/5.jpg)
Background cont.
Why is ozone assimilated? LW and SW radiation schemes need realistic ozone. Used to extract correct temperature component from the ozone
sensitive HIRS channels. Biggest impacts in terms of temperature and dynamics and
should occur in the UT/LS.• Won't improve short term skill (days 1-3)
• But should improve days >3
Ozone forecasts used in UV Index forecasts. Used for boundary conditions in Air Quality forecasts.
![Page 6: Assimilation of OMI Data Into NCEP’s GFS](https://reader033.vdocuments.site/reader033/viewer/2022061410/56814e67550346895dbc04cb/html5/thumbnails/6.jpg)
OMI
GFS
OMI Comparison with GFS using SBUV/2
OMI shows finer structure than the GFS, e.g., the relatively high ozone off the East coast is captured by OMI but
missed by GFS.
![Page 7: Assimilation of OMI Data Into NCEP’s GFS](https://reader033.vdocuments.site/reader033/viewer/2022061410/56814e67550346895dbc04cb/html5/thumbnails/7.jpg)
November 11, 2005
SBUV/2 only Adding OMI TOMS obs.
Adding OMI makes 5 day total ozone forecast agree more with NASA/TOMS
![Page 8: Assimilation of OMI Data Into NCEP’s GFS](https://reader033.vdocuments.site/reader033/viewer/2022061410/56814e67550346895dbc04cb/html5/thumbnails/8.jpg)
November 12, 2005
SBUV/2 only Adding OMI TOMS obs.
![Page 9: Assimilation of OMI Data Into NCEP’s GFS](https://reader033.vdocuments.site/reader033/viewer/2022061410/56814e67550346895dbc04cb/html5/thumbnails/9.jpg)
November 13, 2005
SBUV/2 only Adding OMI TOMS obs.
![Page 10: Assimilation of OMI Data Into NCEP’s GFS](https://reader033.vdocuments.site/reader033/viewer/2022061410/56814e67550346895dbc04cb/html5/thumbnails/10.jpg)
November 14, 2005
SBUV/2 only Adding OMI TOMS obs.
![Page 11: Assimilation of OMI Data Into NCEP’s GFS](https://reader033.vdocuments.site/reader033/viewer/2022061410/56814e67550346895dbc04cb/html5/thumbnails/11.jpg)
November 15, 2005
SBUV/2 only Adding OMI TOMS obs.
end
![Page 12: Assimilation of OMI Data Into NCEP’s GFS](https://reader033.vdocuments.site/reader033/viewer/2022061410/56814e67550346895dbc04cb/html5/thumbnails/12.jpg)
OMI Issues• Conflicts with SBUV/2 at high SZA
Also SBUV/2 is V6 product Is V8 much different? Where? When?
• Noise in some channels affects TO3 at high SZA Cloud climatology may degrade quality of TO3
• Comparisons with DOAS products DOAS has striping But, better estimate of cloud top heights
• High density of data 840 points per single SBUV/2 ob Needs thinning
• Comparisons with surface obs
![Page 13: Assimilation of OMI Data Into NCEP’s GFS](https://reader033.vdocuments.site/reader033/viewer/2022061410/56814e67550346895dbc04cb/html5/thumbnails/13.jpg)
N16 SBUV/2 & OMTO3 Nadir Total Ozone - 20051023
140160180200
220240260280300320340360
380400420440
-90 -80 -70 -60 -50 -40 -30 -20 -10 0 10 20 30 40 50 60 70 80 90
Tot
al O
zon
e (D
U)
N16 OMTO3
![Page 14: Assimilation of OMI Data Into NCEP’s GFS](https://reader033.vdocuments.site/reader033/viewer/2022061410/56814e67550346895dbc04cb/html5/thumbnails/14.jpg)
Comparison between OMTO3 (NASA/TOMS) and OMDOAO3 (KNMI/DOAS)
![Page 15: Assimilation of OMI Data Into NCEP’s GFS](https://reader033.vdocuments.site/reader033/viewer/2022061410/56814e67550346895dbc04cb/html5/thumbnails/15.jpg)
![Page 16: Assimilation of OMI Data Into NCEP’s GFS](https://reader033.vdocuments.site/reader033/viewer/2022061410/56814e67550346895dbc04cb/html5/thumbnails/16.jpg)
OMTO3 vs OMDOAO3 Zonal Mean Total Ozone
Mean may average out to near zero, but variability is quite high!
![Page 17: Assimilation of OMI Data Into NCEP’s GFS](https://reader033.vdocuments.site/reader033/viewer/2022061410/56814e67550346895dbc04cb/html5/thumbnails/17.jpg)
Striping in DOAS Total ozone makes it unusable
![Page 18: Assimilation of OMI Data Into NCEP’s GFS](https://reader033.vdocuments.site/reader033/viewer/2022061410/56814e67550346895dbc04cb/html5/thumbnails/18.jpg)
TOMS and SBUV/2 V8 Clim Cloud Tops Results in Total Ozone being too High
![Page 19: Assimilation of OMI Data Into NCEP’s GFS](https://reader033.vdocuments.site/reader033/viewer/2022061410/56814e67550346895dbc04cb/html5/thumbnails/19.jpg)
DOAS Cloud Top PressuresOMTO3 Cloud Top Pressures
OMTO3 Cloud Top Pressure Climatology Issue
0 10000 1000500 500
![Page 20: Assimilation of OMI Data Into NCEP’s GFS](https://reader033.vdocuments.site/reader033/viewer/2022061410/56814e67550346895dbc04cb/html5/thumbnails/20.jpg)
OMTO3 using cloud own climatology OMTO3 using DOAS cloud top heights
If DOAS Cloud Top Pressures are used,OMTO3 Total Ozone usually is lower
208 258 208 258
![Page 21: Assimilation of OMI Data Into NCEP’s GFS](https://reader033.vdocuments.site/reader033/viewer/2022061410/56814e67550346895dbc04cb/html5/thumbnails/21.jpg)
OMI N-17 SBUV/2 N-16 SBUV/2
(12Z)
GSI vs SSI
![Page 22: Assimilation of OMI Data Into NCEP’s GFS](https://reader033.vdocuments.site/reader033/viewer/2022061410/56814e67550346895dbc04cb/html5/thumbnails/22.jpg)
SBUV/2 only (N16,N17)
OMI only
SBUV/2 andOMI
GSI SSI
Total Ozone increment (DU)
![Page 23: Assimilation of OMI Data Into NCEP’s GFS](https://reader033.vdocuments.site/reader033/viewer/2022061410/56814e67550346895dbc04cb/html5/thumbnails/23.jpg)
SBUV/2 only
OMI only
SBUV/2 and OMI
GSI – SSI differences
![Page 24: Assimilation of OMI Data Into NCEP’s GFS](https://reader033.vdocuments.site/reader033/viewer/2022061410/56814e67550346895dbc04cb/html5/thumbnails/24.jpg)
Data Thinning• There are many ways to thin massive amounts of sat. obs.
• Experimentation is only way to determine best density: Sometimes “less is more”
• OMI vs SBUV # of obs 60 OMI obs/scan x 14 scans/SBUV retrieval
Or 840 points per SBUV retrieval
~76,000 points per orbit
• Need to restrict OMI to quality data points
• Thin by selection Fewer points in flat regions - more points in dynamic regions
Background errors may be adjusted to be more sensitive in dynamic regions
• Thin by averaging Uniform coverage
Average out noisy data
![Page 25: Assimilation of OMI Data Into NCEP’s GFS](https://reader033.vdocuments.site/reader033/viewer/2022061410/56814e67550346895dbc04cb/html5/thumbnails/25.jpg)
Flat region Dynamic regions
![Page 26: Assimilation of OMI Data Into NCEP’s GFS](https://reader033.vdocuments.site/reader033/viewer/2022061410/56814e67550346895dbc04cb/html5/thumbnails/26.jpg)
Dynamic ozoneregionsFlat region
![Page 27: Assimilation of OMI Data Into NCEP’s GFS](https://reader033.vdocuments.site/reader033/viewer/2022061410/56814e67550346895dbc04cb/html5/thumbnails/27.jpg)
Total Ozone Variability within Scan - 20051023
0
10
20
30
40
50
60
70
80
-90 -80 -70 -60 -50 -40 -30 -20 -10 0 10 20 30 40 50 60 70 80 90
Var
iab
ilit
y w
ith
in S
can
(D
U)
Orb1 Orb2 Orb3 Orb4 Orb5 Orb6 Orb7 Orb8 Orb9 Orb10 Orb11 Orb12 Orb13 Orb14
Dynamic ozoneregions
Flat region
![Page 28: Assimilation of OMI Data Into NCEP’s GFS](https://reader033.vdocuments.site/reader033/viewer/2022061410/56814e67550346895dbc04cb/html5/thumbnails/28.jpg)
Data thinning method tested
• Method: averaging data in 1o x 1o model grid box.
• Selection: when there are overlapped data from multiple orbits within a 1o x 1o box, select data only from one major orbit.
• Reduction: total number of data is reduced to ~ 6%.
![Page 29: Assimilation of OMI Data Into NCEP’s GFS](https://reader033.vdocuments.site/reader033/viewer/2022061410/56814e67550346895dbc04cb/html5/thumbnails/29.jpg)
OMI N-17 SBUV/2 N-16 SBUV/2
(12Z)
![Page 30: Assimilation of OMI Data Into NCEP’s GFS](https://reader033.vdocuments.site/reader033/viewer/2022061410/56814e67550346895dbc04cb/html5/thumbnails/30.jpg)
1o (lat) x 1o (lon) thinning
12Z
From ~ 76,000 obs per orbit to ~ 4000
![Page 31: Assimilation of OMI Data Into NCEP’s GFS](https://reader033.vdocuments.site/reader033/viewer/2022061410/56814e67550346895dbc04cb/html5/thumbnails/31.jpg)
1o (lat) x 2o (lon) thinning
12Z
From ~ 76,000 obs per orbit to ~ 2000
![Page 32: Assimilation of OMI Data Into NCEP’s GFS](https://reader033.vdocuments.site/reader033/viewer/2022061410/56814e67550346895dbc04cb/html5/thumbnails/32.jpg)
DU
Ozone difference of thinning and non-thinning (GSI)SBUV/2 and OMI
![Page 33: Assimilation of OMI Data Into NCEP’s GFS](https://reader033.vdocuments.site/reader033/viewer/2022061410/56814e67550346895dbc04cb/html5/thumbnails/33.jpg)
DU
GSI and SSI TOZ difference (1o x 1o thinning)
![Page 34: Assimilation of OMI Data Into NCEP’s GFS](https://reader033.vdocuments.site/reader033/viewer/2022061410/56814e67550346895dbc04cb/html5/thumbnails/34.jpg)
GSI and SSI TOZ difference (1o x 2o thinning)
DU
![Page 35: Assimilation of OMI Data Into NCEP’s GFS](https://reader033.vdocuments.site/reader033/viewer/2022061410/56814e67550346895dbc04cb/html5/thumbnails/35.jpg)
Summary
OMI adds additional information in horizontal
OMI data have issues to be rectified Are ways to improve it!
GSI assimilation of OMI data not significantly different from SSI
![Page 36: Assimilation of OMI Data Into NCEP’s GFS](https://reader033.vdocuments.site/reader033/viewer/2022061410/56814e67550346895dbc04cb/html5/thumbnails/36.jpg)
What’s Next
• Move to Aqua computer when available.
• Continue experimenting with thinning options.– Quality assessment of data
• Assess impacts in forecast mode.– Determine resolution dependence
– Impacts to temperatures and dynamics
– Strive for improvement in multi-day forecasts.
• Begin looking at OMI profile products– Profile total ozone may be better than ‘best’ ozone
– Additional profiles
• Use March 2006 as test month
• Compare profiles with ozonesonde and Lidar data.
• HIRDLS data
![Page 37: Assimilation of OMI Data Into NCEP’s GFS](https://reader033.vdocuments.site/reader033/viewer/2022061410/56814e67550346895dbc04cb/html5/thumbnails/37.jpg)
fini
![Page 38: Assimilation of OMI Data Into NCEP’s GFS](https://reader033.vdocuments.site/reader033/viewer/2022061410/56814e67550346895dbc04cb/html5/thumbnails/38.jpg)
MLS
OMI
TESHIRDLS
EOS AURA was launched in July 2004, which has 4 ozone measuring instruments.
![Page 39: Assimilation of OMI Data Into NCEP’s GFS](https://reader033.vdocuments.site/reader033/viewer/2022061410/56814e67550346895dbc04cb/html5/thumbnails/39.jpg)
Aura instruments
• OMI (ozone Monitoring Instrument)– total ozone and ozone profile, high horizontal resolution
• HIRDLS (High Resolution Dynamics Limb Sounder)
– ozone profile, high vertical resolution (1.25 km, 10-80 km)
• MLS (Microwave Limb Sounder)– ozone profile (3 km, 8-50 km)
• TES (Tropospheric Emission Spectrometer)
– tropospheric ozone (0-34 km)