Spaceborne Doppler Wind Lidars - Scientific motivation and impact studies for ADM/Aeolus

Slide 1

Wind Lidar working group February 2010 Slide 1

Spaceborne Doppler Wind Lidars-

Scientific motivation and impact studies for ADM/Aeolus

Erland Källén

with help from

David Tan, Carla Cardinali, Paul Berrisford

ECMWF

Slide 2


OutlineADM/Aeolus

Scientific motivation Present observing system

Forecast error Sensitivity to Observations

Re-analysis uncertainties

ADM/Aeolus impact study

Conclusions

Slide 3


Atmospheric Dynamics Mission ADM/Aeolus

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[H]LOS

ADM-Aeolus

•Doppler Lidar

•Aerosol and molecular scattering

•Intermittent pulses

•Only one wind component

•Dawn-dusk polar orbit

•Measurement error < 2 m/s

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ADM/Aeolus

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Main scientific objectives of ADM/Aeolus

Improve representation of wind field

in atmospheric analyses Tropics: Wind field governs dynamics Mid-latitudes: Intense storm developments

and meso-scale circulation systems

Numerical weather prediction

Climate sensitivity

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Additional objectives

Aerosol information

Cloud properties

Slide 8


Outline

ADM/Aeolus





Conclusions

Slide 9


Present observing system

Radiosondes

Pilot balloons and profilers

Buoys

Satellites

Aircraft data

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Radiosondes1 Nov 2004, ECMWF Total: 590

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Satellite polar orbiting1 Nov 2004, ECMWF Total: 247309

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Aircraft data1 Nov 2004, ECMWF Total 26219

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Outline

ADM/Aeolus





Conclusions

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a b bx = x + K(y - Hx )Analysis solution:

a

a

J J

x

y y x

Forecast error sensitivity to the analysis xa:

a

Jx

, ( )b

J JFEC J

y y Hxy y

1

a

J J

R HA

y x

Rabier F, et al. 1996.

Compute the δJ:

Forecast error J (“dry energy norm” ps, T, u, v)

1Ta

x

K R HAy

The tool provides the

Forecast Error Contribution

for each assimilated observation, which can be accumulated by observation type, subtype, variable or level

→ (y: observations)

→

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24 H Forecast Error Contribution of GOS

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Mass versus Wind contributions

0

10

20

30

40

50

60

70

Conventional-wind Conventional-mass Satellite-wind Satellite-mass

FC

E %

Total per OBS

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Outline

ADM/Aeolus





Conclusions

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Re-analyses of zonal winds

Kistler et al., 2001

NCEP ERA-15

Difference

NCEP/ERA-15

Slide 19


ERA-InterimZonal mean wind 1989-2001

m/s

>15

>30

30>25

<-10

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Difference ERA-Interim vs. ERA-40 Zonal mean wind 1989-2001

m/s

>2

<-4

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Outline

ADM/Aeolus





Conclusions

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Assimilation study for ADM/Aeolus

Assimilation ensembles for data impact assessment

Use ensemble spread as proxy for short-range forecast errors (background errors)

By extension, good data reduce ensemble spread

DWL impact

Radiosonde/profiler impact - provides calibration

Tan et al., QJRMS 133:381-390 (2007)

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Reference ResultVerificationNWP-SystemObservations

Reference ResultAn & FcDiagnostics

NWP-SystemEnsembleObservations

OSEOSE

Assimilation EnsembleAssimilation Ensemble

Real atmosphere

Assimilation/ forecast


Compare to reference

Compare to reference

Impact assessment

Ref. run



Ensemble spread

Ensemble spread

Assimilation/ forecast Ensemble spread

Calibrate

Impact assessment

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-0.1

0.1 0.1

0.1

80 S 80 S

60 S60 S

40 S 40 S

20 S20 S

0 0

20 N20 N

40 N 40 N

60 N60 N

80 N 80 N

120 W

120 W 60 W

60 W 0

0 60 E

60 E 120 E

120 E

Thursday 16 January 2003 12UTC ECMWF Forecast t+12 VT: Friday 17 January 2003 00UTC 500hPa **u-velocity

-2.6

-2.2

-1

-0.4

-0.3

-0.2

-0.1

0.1

0.2

0.3

0.4

1

2.2

2.6

-0.1

-0.1

0.1

80 S 80 S

60 S60 S

40 S 40 S

20 S20 S

0 0

20 N20 N

40 N 40 N

60 N60 N

80 N 80 N

120 W

120 W 60 W

60 W 0

0 60 E

60 E 120 E

120 E


-2.6

-2.2

-1

-0.4

-0.3

-0.2

-0.1

0.1

0.2

0.3

0.4

1

2.2

2.6

-0.1

0.1 0.1

0.1

80 S 80 S

60 S60 S

40 S 40 S

20 S20 S

0 0

20 N20 N

40 N 40 N

60 N60 N

80 N 80 N

120 W

120 W 60 W

60 W 0

0 60 E

60 E 120 E

120 E


-2.6

-2.2

-1

-0.4

-0.3

-0.2

-0.1

0.1

0.2

0.3

0.4

1

2.2

2.6

-0.1

-0.1

0.1

80 S 80 S

60 S60 S

40 S 40 S

20 S20 S

0 0

20 N20 N

40 N 40 N

60 N60 N

80 N 80 N

120 W

120 W 60 W

60 W 0

0 60 E

60 E 120 E

120 E


-2.6

-2.2

-1

-0.4

-0.3

-0.2

-0.1

0.1

0.2

0.3

0.4

1

2.2

2.6

Data impact on ensemble forecasts - zonal wind spread at 500 hPa

Sondes

60°S60°S

30°S 30°S

0°0°

30°N 30°N

60°N60°N

150°W

150°W 120°W

120°W 90°W

90°W 60°W

60°W 30°W

30°W 0°

0° 30°E

30°E 60°E

60°E 90°E

90°E 120°E

120°E 150°E

150°E


0.75

0.9

1.05

1.2

1.35

1.5

1.65

1.8

1.95

2.1

2.25

Control

ADM-Aeolus

Radiosondes and wind

profilers over Japan,

Australia, N.Amer, Europe

DWL over oceans & tropics

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60°S60°S

30°S 30°S

0°0°

30°N 30°N

60°N60°N

150°W

150°W 120°W

120°W 90°W

90°W 60°W

60°W 30°W

30°W 0°

0° 30°E

30°E 60°E

60°E 90°E

90°E 120°E

120°E 150°E

150°E

NH=-0.03 SH= -0.04 Trop= -0.17 Eur=-0.02 NAmer= 0.02 NAtl= -0.02 NPac= -0.04Lev=200, Par=u, FcDate=20030116-20030228 12Z, Step=12

RMS of Ensemble fcspread: RMS(fcspread_emi1_emi2_emi3_emi4) - RMS(fcspread_em9l_em9m_em9n_em9o)

-1

-0.8

-0.6

-0.4

-0.2

-0.1

-0.040.04

0.1

0.2

0.4

0.6

0.8

1

60°S60°S

30°S 30°S

0°0°

30°N 30°N

60°N60°N

150°W

150°W 120°W

120°W 90°W

90°W 60°W

60°W 30°W

30°W 0°

0° 30°E

30°E 60°E

60°E 90°E

90°E 120°E

120°E 150°E

150°E

NH=-0.03 SH= -0.05 Trop= -0.09 Eur=-0.06 NAmer= -0.03 NAtl= 0 NPac= -0.04Lev=200, Par=u, FcDate=20030116-20030228 12Z, Step=12

RMS of Ensemble fcspread: RMS(fcspread_em9l_em9m_em9n_em9o) - RMS(fcspread_embd_embe_embf_embg)

-1

-0.8

-0.6

-0.4

-0.2

-0.1

-0.040.04

0.1

0.2

0.4

0.6

0.8

1

Data impact on ensemble forecasts - zonal wind spread at 200 hPa

Sondes

60°S60°S

30°S 30°S

0°0°

30°N 30°N

60°N60°N

150°W

150°W 120°W

120°W 90°W

90°W 60°W

60°W 30°W

30°W 0°

0° 30°E

30°E 60°E

60°E 90°E

90°E 120°E

120°E 150°E

150°E


0.75

0.8

1

1.2

1.4

1.6

1.8

2

2.2

2.4

2.6

2.8

Control

ADM-Aeolus

Radiosondes and wind

profilers over Japan,

Australia, N.Amer, Europe

DWL over oceans and

tropics

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Conclusions

Wind data is lacking in present global

observing system Tropical analyses suffer

Climate system re-analyses uncertain in tropics, polar areas and stratosphere

ADM/Aeolus will provide vertical wind

profiles with global coverage

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Thank you for your attention– questions?

Documents

Spaceborne Doppler Wind Lidars - Scientific motivation and impact studies for ADM/Aeolus