Three major sets of OSEs

ECMWFWMO Workshop19-21 May 2008: ECMWF OSEs Slide 1

A summary of OSE and OSSE activities at ECMWF.

Erik Andersson, Graeme Kelly, Jean-Noël Thépaut, Gabor Radnoti, Peter Bauer and Sean Healy

Acknowledgements:EUCOS, EUMETSAT, JCSDA/NCEP

Three major sets of OSEs Investigating the complementarity between space based and terrestrial observing systems The impact of MetOP instruments Impact of GPS Radio Occultation data The Joint-OSSE, followed by Conclusions


1: The Space-Terrestrial StudyInitiated and funded by EUCOS.

i. BASELINE: all satellite observations currently used in NWP (radiances, cloud-drift winds, scatt winds) + GUAN R/S + GSN surface land data + buoys (no ship data)

ii. BASELINE + aircraft data

iii. BASELINE + non-GUAN R/S wind profiles

iv. BASELINE + non-GUAN R/S wind and temp profiles

v. BASELINE + wind-profiler data

vi. (iv) + aircraft data

vii. BASELINE + non-GUAN R/S wind, temp and humidity profiles

viii.CONTROL: the combined observing system ix. BASELINE + non-GUAN R/S temperature profiles (winter)

x. BASELINE + aircraft temperature data (winter)


OSE assimilation system configuration

Resolutions:Model resolution T511 (50 km), L60Analysis at T511/T159 L60,12-hour 4D-Var

Winter Experiments:20041204-00 to 20050125-12 (including 10 day warm up)Model cycle 29R1

Summer experiments:20050715-00 to 20050915-12 (including 10 day warm up)Model cycle 29R2NOAA18 included (AMSU-A and MHS)


Winter results: Baseline – Control (Z500)Impact of terrestrial, non-climate, observations

NH

EUR


Control-Baseline (Z500)Normalised forecast error difference, Day-3


Z scores: Impact of R/S

NH

EUR

1000 hPa 500 hPa


Baseline – [ Baseline + aircraft]Z500 Impact of aircraft data

NH

EUR


[Baseline + aircraft] - Baseline (Z500)Normalised forecast error difference FC+12h


Z scores: Impact of aircraft

NH

EUR

1000 hPa 500 hPa


Wind scores: Impact of aircraft

NH

EUR

850 hPa 300 hPa


[(i) + R/S T+W] – [ (i) + R/S T+W + aircraft]Z500 Impact of aircraft in the presence of R/S

NH

EUR


[(i) + R/S T+W + aircraft] – [(i) + R/S T+W] (Z500)Z500 Impact of aircraft in the presence of R/S


[(i) + R/S T+W] – [ (i) + R/S T+W + aircraft]W300 Impact of aircraft in the presence of R/S

NH

EUR


[(i) + aircraft] – [ (i) + R/S T+W + aircraft]W300 Impact of R/S in the presence of aircraft

NH

EUR


[(i) + R/S T+W] – [ (i) + R/S T+W+Q]RH700 Impact of R/S humidity

NH

EUR


EUCOS Space-Terrestrial, Conclusions (1)

Even in presence of satellite observations, degrading the current terrestrial Observing System has a significant negative impact on the forecast skill.

Starting from the degraded baseline (GUAN+GSN+…):

Additional R/S (T+Wind) and aircraft (T+Wind) contribute more or less equally to the Observing System (slight advantage for R/S)

These two Observing Systems are complementary

Aircraft add forecast skill to R/SR/S add forecast skill to Aircraft



R/S impact:

R/S winds contribute little on their own

Radiosonde T contribute marginally more

This is the combination of wind/T which really provides the impact of the RS on the forecast skill

Aircraft impact:

The results are consistent with that of R/S. Aircraft-T alone bring relatively little. Combination of T/Wind makes a big impact



Humidity from R/S add very little in terms of scoresNoticeable but small impact on relative humidity

scores up to day 3

Impact of wind profilers:Winter impact:

The short range forecasts are improved by the US and japanese profilers

The signal blurs away after day 4-5 and large scale interactions appear

European profilers do not bring much

In summer, the impact is smaller than during the winter period (in absolute but also relative terms)


2a: Assessment of the space component of the GOSInitiated and funded by EUMETSAT

Winter period: 20041204-20050125, Summer period: 20050715-20050915 (cycle 29r1)

BASELINE all conventional observations used in NWP (radiosonde + aircraft + profiler network + surface land data + buoy observations + ship data)

REFERENCE= BASELINE + AMVs from GEO+MODIS REFERENCE + HIRS radiances REFERENCE + AMSUA radiances REFERENCE + AMSUB radiances REFERENCE + SSMI radiances REFERENCE + GEO Clear Sky Radiances (CSRs) REFERENCE + AIRS radiances REFERENCE + SCAT winds BASELINE + GEO AMVs (no MODIS)


2b: Assessment of the space component of the GOSInitiated and funded by EUMETSAT

Winter period: 20061205-20070214 (31r1), Summer period: 20060601-20060815 (31r2)

i. BASELINE all conventional observations used in NWP (radiosonde + aircraft + profiler network + surface land data + buoy observations + ship data)

ii. REFERENCE= BASELINE + AMSUA Noaa 16

iii. REFERENCE + AMVs from GEO+MODIS

iv. REFERENCE + AMSUA radiances

v. REFERENCE + AMSUB radiances

vi. REFERENCE + GEO Clear Sky Radiances (CSRs)

vii. REFERENCE + AIRS radiances

viii. REFERENCE + SCAT winds

ix. CONTROL full operational system (all above observations)


Average Z 500 anomaly correlation scoresThe AMV reference and the AMSU-A reference

All AMVs ref All AMVs ref

One AMSU_A ref One AMSUA_ ref

S.Hem

N.Hem

N.Hem

S.Hem


Z500 impacts, S.Hem (REFERENCE_AMV)

HIRS, AMSU-A, AIRS

AMSU-B, SSMI, GEO_CSR

Scat, GEO_AMV, GEO_CSR


Relative Humidity 850hPa impacts, S.Hem (REFERENCE_AMV)

HIRS, AMSU-A, AIRS




Vector wind 200 hPa impacts, S.Hem (REFERENCE_AMV)

HIRS, AMSU-A, AIRS




Impact of removing MODIS from the REFERENCE_AMV


Space component, Summary

Very encouraging that all the space base sensors contribute in a positive way to the overall performance of the ECMWF forecast system. Sensors like AMSU-A, AIRS and HIRS are the most important.

The humidity analysis requires AMSUB (also MHS), GEO CSRs and SSMI.

Amongst the wind data, SCAT has a clear positive impact on the surface wind in the Southern Hemisphere, and a clear beneficial impact of AMVs and MODIS winds has been demonstrated.


3: OSEs for the evaluation of degraded EPS/Post-EPS instrument scenarios (EUMETSAT)

The objective is to assess the detrimental impact of potential loss of the main EUMETSAT Polar System (EPS) instruments on global NWP.

REFERENCE: All conventional data + 2*AMSU-A, 2* DMSP, AIRS and IASI, ASCAT and QuikSCAT.

REFERENCE – HIRS REFERENCE – AMSU REFERENCE – MHS REFERENCE – SOUNDERS REFERENCE – IASI REFERENCE – ASCAT REFERENCE – METOP


METOP forecast impact500 hPa geopotential height RMS error difference

when METOP data withdrawn

[%/100]

T+12 hours

T+24 hours


Preliminary results on Metop (ongoing study)

The fit to temperature-sounding instruments (e.g. NOAA-18 AMSU-A) is improved when Metop instruments are present.

The fit to moisture-sounding instruments (e.g. AIRS, MHS, GOES) is improved when Metop MHS, all Metop sounders or IASI are present

The presence of ASCAT data slightly improves the fit to QuikSCAT wind data, and products from Envisat and Jason altimeters

The synergy of Metop instruments produces a much stronger impact than its individual instruments


GPS radio-occultation. Current 6-hour data coverage.


December 2006: Assimilation of RO data at ECMWF

All 6 satellites

Wave-like bias disappeared


Population: 66Confidence: 95%

1000hPa Geopotential 00UTCDate: 20061215 00UTC to 20070218 00UTC

S.hem Lat -90.0 to -20.0 Lon -180.0 to 180.0Root mean square error forecast

control normalised beuwz minus beuwy

0 1 2 3 4 5 6 7 8 9 10 11Forecast Day

-0.05

0

0.05

0.1

0.15Population: 66

Confidence: 95%500hPa Geopotential 00UTC

Date: 20061215 00UTC to 20070218 00UTCS.hem Lat -90.0 to -20.0 Lon -180.0 to 180.0

Root mean square error forecastcontrol normalised beuwz minus beuwy

0 1 2 3 4 5 6 7 8 9 10 11Forecast Day

-0.05

0

0.05

0.1

0.15




control normalised beuwz minus beuwy

0 1 2 3 4 5 6 7 8 9 10 11Forecast Day

-0.05

0

0.05

0.1

0.15Population: 66



Root mean square error forecastcontrol normalised beuwz minus beuwy

0 1 2 3 4 5 6 7 8 9 10 11Forecast Day

-0.05

0

0.05

0.1

0.15

GPSRO impact on Southern hemisphere geopotential height forecasts

6 COSMICs+CHAMP+GRACE-A (setting only, z > 5 km) – no GPSRO1100 observations/day, 66 cases, winter 2006/2007, own analyses

1000 hPa 500 hPa

200 hPa 100 hPa

(Sean Healy)





control normalised beuwy minus beux1

0 1 2 3 4 5 6 7 8 9 10 11Forecast Day

-0.05

0

0.05

0.1

0.15Population: 66



Root mean square error forecastcontrol normalised beuwy minus beux1

0 1 2 3 4 5 6 7 8 9 10 11Forecast Day

-0.05

0

0.05

0.1

0.15




control normalised beuwy minus beux1

0 1 2 3 4 5 6 7 8 9 10 11Forecast Day

-0.05

0

0.05

0.1

0.15Population: 66



Root mean square error forecastcontrol normalised beuwy minus beux1

0 1 2 3 4 5 6 7 8 9 10 11Forecast Day

-0.05

0

0.05

0.1

0.15

GPSRO impact on Southern hemisphere geopotential height forecasts

6 COSMICs+CHAMP+GRACE-A (setting+rising, z > 5 km) – no GPSRO1600 observations/day, 66 cases, winter 2006/2007, own analyses

1000 hPa 500 hPa

200 hPa 100 hPa

(Sean Healy)


Advanced infrared sounders: AIRS and IASI

AIRS Operational at ECMWF since

October 2003. 324 channels received in NRT. One FOV in nine used. Up to 155 channels may be

assimilated (CO2 and H2O bands).

IASI Operational at ECMWF since June

2007. 8461 channels received in NRT. All FOVS received; only 1-in-4 used. 366 Channels routinely monitored. Up to 168 channels may be

assimilated (CO2 band only).


IASIbetterIASI

worse

IASIbetterIASI

worseSH

NH

500 hPa geopotential anomaly correlation (56 cases, spring 2007, normalized RMSE difference, own analysis)

Mean error difference uncertainty

IASI forecast impact


Choosing 10 IASI Water Vapour Channels


Fit to other observations

Increasing assumed IASI H2O channels’ error

No

rmal

ized

An

aly

sis

De

par

ture

Std

. De

v.

Best value at 1.5K

∞


The Joint OSSE Nature RunCollaboration with NCEP (Michiko Masutani) to plan,

produce, deliver and evaluate the NR. Consultation with the Joint-OSSE group in the US, EUCOS, ESA, EUMETSAT and ECMWF

T511 NR: 13 months T511/L91.

Data set size ~2.5 Tbyte. Shipping to the US on 4 disks

Yearly, quarterly and monthly comparison with climate and observations = 831 plots. Posted on NCEP web site

Extensive evaluation of the NR by US partners

T799 NR: Two 6-week periods have been run at T799/L91 with hourly post processing: TC-season, Convective season


Nature Run, 12-month total cloud cover

35

65 65

65

65

65

65

65

65

65

95

60°S60°S

30°S 30°S

0°0°

30°N 30°N

60°N60°N

135°W

135°W 90°W

90°W 45°W

45°W 0°

0° 45°E

45°E 90°E

90°E 135°E

135°E

Total Cloud Cover eskb June 2005 nmon=12 nens=1 Global Mean: 62.6 50N-S Mean: 57.8

[percent]

5.165

20

35

50

65

80

95

97.71

35

65

6565

65

65

6565

95 959595

60°S60°S

30°S 30°S

0°0°

30°N 30°N

60°N60°N

135°W

135°W 90°W

90°W 45°W

45°W 0°

0° 45°E

45°E 90°E

90°E 135°E

135°E

Total Cloud Cover MODIS June 2005 nmo2001-2001 climatology 50N-S Mean: 68.9

[percent]

5

20

35

50

65

80

95

101.2

10

50

60°S60°S

30°S 30°S

0°0°

30°N 30°N

60°N60°N

135°W

135°W 90°W

90°W 45°W

45°W 0°

0° 45°E

45°E 90°E

90°E 135°E

135°E

Difference eskb - MODIS 50N-S Mean err -11.1 50N-S rms 13.7[percent]

-53.03

-50

-40

-30

-20

-10

10

20

30

40

50

57.29

80 60 40 20 0 -20 -40 -60 -80

latitude (deg)

50

60

70

80

90

Zonal Meanmodel obs

-180 -120 -60 0 60 120 180

longitude (deg)

60

70

80

Extra-Tropics: Lat20

model obs

-180 -120 -60 0 60 120 180

longitude (deg)

50

60

70

80

Tropics: Lat20m odel obs


Nature Run, 12-month total cloud cover, difference with respect to MODIS observations

35

65 65

65

65

65

65

65

65

65

95

60°S60°S

30°S 30°S

0°0°

30°N 30°N

60°N60°N

135°W

135°W 90°W

90°W 45°W

45°W 0°

0° 45°E

45°E 90°E

90°E 135°E

135°E

Total Cloud Cover eskb June 2005 nmon=12 nens=1 Global Mean: 62.6 50N-S Mean: 57.8

[percent]

5.165

20

35

50

65

80

95

97.71

35

65

6565

65

65

6565

95 959595

60°S60°S

30°S 30°S

0°0°

30°N 30°N

60°N60°N

135°W

135°W 90°W

90°W 45°W

45°W 0°

0° 45°E

45°E 90°E

90°E 135°E

135°E

Total Cloud Cover MODIS June 2005 nmo2001-2001 climatology 50N-S Mean: 68.9

[percent]

5

20

35

50

65

80

95

101.2

10

50

60°S60°S

30°S 30°S

0°0°

30°N 30°N

60°N60°N

135°W

135°W 90°W

90°W 45°W

45°W 0°

0° 45°E

45°E 90°E

90°E 135°E

135°E

Difference eskb - MODIS 50N-S Mean err -11.1 50N-S rms 13.7[percent]

-53.03

-50

-40

-30

-20

-10

10

20

30

40

50

57.29

80 60 40 20 0 -20 -40 -60 -80

latitude (deg)

50

60

70

80

90

Zonal Meanmodel obs

-180 -120 -60 0 60 120 180

longitude (deg)

60

70

80

Extra-Tropics: Lat20

model obs

-180 -120 -60 0 60 120 180

longitude (deg)

50

60

70

80

Tropics: Lat20m odel obs


Comparison of extra-tropical cyclones in the NR against cyclones in the NCEP analyses for 5 recent years (green bars), showing central pressure (hPa, left) and life span (days, right panel). Courtesy Joe Terry (NASA).

18. 5.


OSEs and OSSE activities at ECMWFConclusions

Space-terrestrial study (EUCOS) completed

Assessment of space-component of the GOS (EUMETSAT) completed

Assessment of Metop impact (EUMETSAT) is ongoing

Comprehensive reports are available

ECMWF Newsletter No 113, page 16-28 (Kelly and Thépaut)

Metop-IASI and GPS-RO constitute significant new additions to the GOS

Joint-OSSE framework being developed, attracting a lot of interest, generating wide-spread collaboration

Documents

Three major sets of OSEs