MODIS Polar Winds in ECMWF’s Data Assimilation System: Long-term Performance and Recent Case Studies Lueder von Bremen, Niels Bormann and Jean-Noël Thépaut European Centre for Medium-Range Weather Forecasts (ECMWF) Reading, United Kingdom High Latitude NWP Workshop at IARC, Fairbanks, 8-10 October 2003
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MODIS Polar Winds in ECMWF’s Data Assimilation System: Long-term Performance and Recent Case Studies Lueder von Bremen, Niels Bormann and Jean-Noël Thépaut.
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MODIS Polar Winds in ECMWF’sData Assimilation System:
Long-term Performance and Recent Case Studies
Lueder von Bremen, Niels Bormann and Jean-Noël Thépaut
European Centre for Medium-Range Weather Forecasts (ECMWF)Reading, United Kingdom
High Latitude NWP Workshop at IARC, Fairbanks, 8-10 October 2003
History and use of MODIS Polar Winds at ECMWF
Long-term performance a) one satellite (Terra) b) two satellites (Terra and Aqua)
Case study
Conclusions and prospects
OUTLINE
History of MODIS AMVs at ECMWF
trial 3DVAR experiments with MODIS Terra AMVs very successful (spring 2001)operational archiving of MODIS Terra AMVs since July 20024DVAR experiments with MODIS Terra AMVs i) 2 study periods (spring 2001 and summer 2002, 58 cases) ii) operational configuration (T159 60L analysis and T511 forecast) iii) usage like geostationary AMVs iv) modification of mean polar wind analyses v) reduction of key analysis errors in case study experiment vi) good impact on forecast over NH (especially over Europe and N. Atlantic)operational use of MODIS AMVs (Terra) since 14 Jan 2003operational archiving of MODIS Aqua AMVs since Feb 2003 monitoring since May 20034DVAR experiments with MODIS Aqua AMVs are described here (operational analysis and model configuration)
FG check: asymmetric to remove negative OBS-FG bias (FG-Dep. is scaled with background error)
Thinning: 2 cycles with different box/volume sizes (96x96km then 140x140km)
wind speed
0 20 40 60 80FG
0
20
40
60
80
SAT
OB
W
VM
V(
163
047)
5
30
10
751
50
300
600
lat: 20 - 90
lon: -180 - 180
p : 400 - 700
wind speed
0 20 40 60 80FG
0
20
40
60
80
SAT
OB
W
VM
V(
235
658)
5
30
10
7515
030
060
0
lat: 20 - 90
lon: -180 - 180
p : 0 - 400
wind speed
0 20 40 60 80FG
0
20
40
60
80
SAT
OB
W
VM
V(
39
548)
5
75
30
10
150
300
600
lat: -90 - -20
lon: -180 - 180
p : 400 - 700
wind speed
0 20 40 60 80FG
0
20
40
60
80
SAT
OB
W
VM
V(
8
484)
510
30
75
lat: -90 - -20
lon: -180 - 180
p : 0 - 400
MODIS TERRA winds WVMV 0001: 2003063006-2003063012 (N= 446737)WV clear 400hPa<h<550hPa
all
FG [m/s]
OB
S [
m/s
]
wind speed
0 20 40 60 80FG
0
20
40
60
80
SAT
OB
W
VM
V(
15
249)
510
3075150
300
lat: 20 - 90
lon: -180 - 180
p : 400 - 700
wind speed
0 20 40 60 80FG
0
20
40
60
80
SAT
OB
W
VM
V(
26
376)
5
10
3075150300
lat: 20 - 90
lon: -180 - 180
p : 0 - 400
wind speed
0 20 40 60 80FG
0
20
40
60
80
SAT
OB
W
VM
V(
3
464)
5
10
30
75
5
lat: -90 - -20
lon: -180 - 180
p : 400 - 700
wind speed
0 20 40 60 80FG
0
20
40
60
80
SAT
OB
W
VM
V(
1
030)
5 10
lat: -90 - -20
lon: -180 - 180
p : 0 - 400
MODIS TERRA winds WVMV 0001_used: 2003062618-2003070900 (N= 46119)
used
FG [m/s]
OB
S [
m/s
]
OBS errors:
AMV
AIREP
PILOT,SONDE
0.0 1.0 2.0 3.0 4.0 5.0 6.0obs error [m/s]
1000.
100.
10.
pres
sure
[hP
a]
500 hPa Z anomaly correlation (58 days)
Bormann and Thépaut,2003(spring 2001 and summer 2002)
LONG-TERM PERFORMANCE
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.1
0.3
0.3
0.3
0.3
0.3
544
560
560
560
560
576
576
576
576
576
40°N
40°N40
°N
40°N
50°N
60°N
70°N
80°N
180°160°W140°W
12
0°W
10
0°W
80
°W6
0°W
40°W 20°W 0° 20°E 40°E
60°E
80°E
100°E
120°E
140°E160°E
0.1
0.2
0.3
0.4
0.5
0.6
0.7
-0.12
-0.04
-0.0
4
-0.0
4
-0.04
-0.0
4
-0.04
-0.04
0.04
0.04
0.04
0.04
0.04
544
560
560
560
560
576
576
576
576
576
40°N
40°N40
°N
40°N
50°N
60°N
70°N
80°N
180°160°W140°W
40°W 20°W 0° 20°E 40°E
60°E
80°E
100°E
120°E
140°E160°E
-0.28
-0.24
-0.2
-0.16
-0.12
-0.08
-0.04
0.04
0.08
0.12
0.16
0.2
0.24
0.28
absolute values Difference Modis-Control
Sensitivity perturbations for streamfunction around 500 hPaPositive impact of MODIS (negative differences) occurs whereSensitivity patterns are large
Sensitivity results: 4 August 2002, 12 Z
FG
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FGFG
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4D
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FGFG
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FG FG
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FG FGFG
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4D
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4D
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FGFG
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4D
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FG FG
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FGFG
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FG FG FG
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FGFG
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FG FGFG
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FGFG
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FGFG
FG FG
FG
FGFGFG
FG
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FGFG
FGFG
FG
FGFGFG FG
FGFG FG
FGFG FG FG
FG
FG FGFG
FG
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FGFG
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FG FGFG
FG
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FGFG
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FG FG FG
FG FG
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FGFG
FG FG
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FG FGFG FG
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FGFG FG
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FGFG
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FGFG
FG
FGFG
FG
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FGFGFG
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FGFG
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FG FG
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FGFG
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FGFG
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FG FG
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FGFG
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FG FG
FG
FGFGFG
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FGFG
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FGFG
FG FG
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FG FG
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FG FG
FG
FGFG
FGFGFG
FG
FGFG FGFG FG
FG
FG
FG FG
FG FG
FGFG
FG
FG FGFG
FGFG
FG
FG
FG
FG
FGFG
FGFG
FG
FG FGFG
FG
FGFG
FG FG
FGFG FG FG
FG FGFG
FG
FGFGFG
FGFGFG
FGFG
FG
FG
FG
FG
FG
FG
FGFG
FGFG
FG
FG
FGFG
FG
FG
FG
FG
FG
FGFG
FG
FGFG
FGFG
FG
FG
FG
FG
FG
FG
FG
FG
FG
FG
FG
FG
FG
FG
FGFG
FG
FG
FG
FG
FG
FG
FG
FG
FG
FG
FG
FG
4D
4D
4D
4D
FGFGFG
FGFG
FG
FGFG FG
FG FG
FG
FG
FG
FGFG
FG
FG
FG
FG FG
FGFG
FG
FG
FG
FG
FG
FG
FG
FG
FGFG
FG
FG
FG
FG
FG
FG
FG
FG
FG
FG
FG
FG
FG
FG
FG
FGFG
FGFGFG
FG
FG
FG FG
FG FG
4D
4D
FG
4D
FG FGFG
FG
FG
FG
FGFG
FG
FG
4D
FG
FG
FG
FG
FG
FG
FGFG
FG
FG
FG
FG
FG
FG
FG
FG
FG
FG
FG
FGFG
FG FG
FG
FG
FG
4D
FG
FGFG
FGFG
FG
FG
FG
FGFG
FG
FG
FG
FG
FG
FGFG 4D
FG
FG
FG
FG
FG
FG
FG
4D FG
FG
FGFG
FG
FG
FG
FG
FG
FG
FG
FG
FG
FG
FG
FG
FGFG
FG
FG
FG
FG
FG
4D 4D
FG
FG
4DFG
FG
FGFG
FG
FG
FG
FG
FGFG
FGFG
FG FG
FG
FG
4D
FG
FGFG
FG
FG
FG
FG
FG
FG
FG
FG
FG
FG
4D
FG
FG
FG4D
FG
4D4D
4D
FG FG
FG
FG
4D
FG
FG
4D
FGFG
FGFG
FG
4D
FG
FG
FG
50°N
50°N
50°N
50°N
60°N
70°N
80°N
180°160°W140°W
120°W
100°W
80°W
60°W
40°W 20°W 0° 20°E 40°E
60°E
80°E
100°E
120°E
140°E160°E
Modis Terra and Aqua data coverage at May 27, 2003 12Z
Light: 06ZDark: 12Z
Experiments with MODIS (Terra and Aqua)
2 study periods Feb. and May 2003, 51 cases revision of MODIS impact in general and clean control to monitor both i) noMODIS (gives chance for clean OBS-FG statistic for Terra and Aqua) ii) Terra (operational usage (140km thinning)) iii) Terra+Aqua (140km thinning) iv) BOTH200km (Terra and Aqua with 200km thinning and QI usage)
stronger OBS-FG bias for Aqua over Antarctic than for Terra
all U MODIS (AQUA) WVCLSATOB-Uwind S.Pole-60efli_784 2003050812-2003051818(24)
Monday 30 June 2003 12UTC ECMWF Forecast t+24 VT: Tuesday 1 July 2003 12UTC 400hPa **geopotential height/ v-velocity
-3-2.5-2-1.5-1-0.500.51
1.522.533.544.55
5.566.57
-1.5
-1
-1
-0.5
-0.5
-0.5
-0.5-0.5
-0.5
-0.5
0
0
0
0
0
0
0
0
0
0.5
0.5
0.50.
5
0.50.
5
0.5
0.5
0.5
0.5
1
1
1
1
1
1
1
1
1.5
1.5
1.5
1.5
1.5
2
2
2
2
2.5
2.53 3.5
4
8.0m/s
80°N
180°170°W160°W150°W140°W
130°W
120°W
110°W
100°W
90°W
80°W
70°W
60°W
50°W
40°W 30°W 20°W 10°W 0° 10°E 20°E 30°E 40°E
50°E
60°E
70°E
80°E
90°E
100°E
110°E
120°E
130°E
140°E150°E160°E170°E
Monday 30 June 2003 12UTC ECMWF Forecast t+24 VT: Tuesday 1 July 2003 12UTC 400hPa **geopotential height/ v-velocity
-3-2.5-2-1.5-1-0.500.51
1.522.533.544.55
5.566.57
BIASBLACK
24h forecast error (400Z) at 30 June 2003, 12UTC
BIASED
-1
-1
-0.5
-0.5
-0.5
-0.5-0.5
-0.5
0
0
0
0
0
0
0
0
0
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
1
1
1
1
1
1
1
1.5
1.5
1.5
1.5
1.5
1.5
2
2
22
2.5
2.5
3
3
3.54
8.0m/s
80°N
180°170°W160°W150°W140°W
130°W
120°W
110°W
100°W
90°W
80°W
70°W
60°W
50°W
40°W 30°W 20°W 10°W 0° 10°E 20°E 30°E 40°E
50°E
60°E
70°E
80°E
90°E
100°E
110°E
120°E
130°E
140°E150°E160°E170°E
Monday 30 June 2003 12UTC ECMWF Forecast t+24 VT: Tuesday 1 July 2003 12UTC 400hPa **geopotential height/ v-velocity
-3-2.5-2-1.5-1-0.500.51
1.522.533.544.55
5.566.57
Operations
-3-2
.5
-2
-2
-1.5
-1.5
-1
-1
-1
-0.5
-0.5
-0.5
-0.5
-0.5
0
0
0
0
0
0
0
0
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
1
1
1
1
1
1.5
1.5
1.5
1.5
2
8.0m/s
80°N
180°170°W160°W150°W140°W
130°W
120°W
110°W
100°W
90°W
80°W
70°W
60°W
50°W
40°W 30°W 20°W 10°W 0° 10°E 20°E 30°E 40°E
50°E
60°E
70°E
80°E
90°E
100°E
110°E
120°E
130°E
140°E150°E160°E170°E
Monday 30 June 2003 12UTC ECMWF Forecast t+24 VT: Tuesday 1 July 2003 12UTC 400hPa **geopotential height/ v-velocity
-3-2.5-2-1.5-1-0.500.51
1.522.533.544.55
5.566.57
noMODIS
-1
-1
-0.5
-0.5
-0.5
-0.5-0.5
-0.5
0
0
0
0
0
0
0
0
0
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
0.5
1
1
1
1
1
1
1
1.5
1.5
1.5
1.5
1.5
1.5
2
2
22
2.5
2.5
3
3
3.54
8.0m/s
80°N
180°170°W160°W150°W140°W
130°W
120°W
110°W
100°W
90°W
80°W
70°W
60°W
50°W
40°W 30°W 20°W 10°W 0° 10°E 20°E 30°E 40°E
50°E
60°E
70°E
80°E
90°E
100°E
110°E
120°E
130°E
140°E150°E160°E170°E
Monday 30 June 2003 12UTC ECMWF Forecast t+24 VT: Tuesday 1 July 2003 12UTC 400hPa **geopotential height/ v-velocity
-3-2.5-2-1.5-1-0.500.51
1.522.533.544.55
5.566.57
[gpdm]
CONCLUSIONS - PROSPECTS
MODIS Polar windshave impact on ECMWFs polar wind analysis (stronger over Antarctic)introduce analysis increments over very bad observed areasare consistent with the other sparse wind observationsimprove forecast over Europeimpact is decreased since much more other satellite data is in the system
2 satellite systemsincrease the spatial coveragemay lead to overfitting (SH) (thinning is an appropriate way to handle this)give potential also for better temporal coverage, ECMWF is encouraging the combination of Terra and Aqua very much (tracking of fast moving systems might be improved substantially (special benefit to 4DVAR))
… challenging isdifference between Terra and Aqua (bias, number of AMVs)usage of ECMWF forecast data for the height assignmentusage of clear sky WV radiances from MODIS