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A summary of OSE and OSSE activities at ECMWF. Erik Andersson, Graeme Kelly, Jean-No

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Erik Andersson, Graeme Kelly, Jean-No l Th paut, Gabor Radnoti, Peter Bauer and Sean Healy Acknowledgements: EUCOS, EUMETSAT, JCSDA/NCEP Three major sets of OSEs – PowerPoint PPT presentation

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Title: A summary of OSE and OSSE activities at ECMWF. Erik Andersson, Graeme Kelly, Jean-No


1
A summary of OSE and OSSE activities at
ECMWF.Erik Andersson, Graeme Kelly, Jean-Noël
Thépaut, Gabor Radnoti, Peter Bauer and Sean
HealyAcknowledgementsEUCOS, 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

2
1 The Space-Terrestrial StudyInitiated and
funded by EUCOS.
  • 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)
  • BASELINE aircraft data
  • BASELINE non-GUAN R/S wind profiles
  • BASELINE non-GUAN R/S wind and temp profiles
  • BASELINE wind-profiler data
  • (iv) aircraft data
  • BASELINE non-GUAN R/S wind, temp and humidity
    profiles
  • CONTROL the combined observing system
  • BASELINE non-GUAN R/S temperature profiles
    (winter)
  • BASELINE aircraft temperature data (winter)

3
OSE assimilation system configuration
  • Resolutions
  • Model resolution T511 (50 km), L60
  • Analysis 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 29R2
  • NOAA18 included (AMSU-A and MHS)

4
Winter results Baseline Control (Z500)Impact
of terrestrial, non-climate, observations
NH
EUR
5
Control-Baseline (Z500)Normalised forecast error
difference, Day-3
6
Z scores Impact of R/S
1000 hPa
500 hPa
NH
EUR
7
T scores Impact of R/S
850 hPa
300 hPa
NH
EUR
8
Wind scores Impact of R/S
850 hPa
300 hPa
NH
EUR
9
Baseline Baseline aircraftZ500 Impact of
aircraft data
NH
EUR
10
Baseline aircraft - Baseline
(Z500)Normalised forecast error difference FC12h
11
Z scores Impact of aircraft
1000 hPa
500 hPa
NH
EUR
12
Wind scores Impact of aircraft
850 hPa
300 hPa
NH
EUR
13
(i) R/S TW (i) R/S TW
aircraftZ500 Impact of aircraft in the presence
of R/S
NH
EUR
14
(i) R/S TW aircraft (i) R/S TW
(Z500)Z500 Impact of aircraft in the presence of
R/S
15
(i) R/S TW (i) R/S TW
aircraftW300 Impact of aircraft in the presence
of R/S
NH
EUR
16
(i) aircraft (i) R/S TW
aircraftW300 Impact of R/S in the presence of
aircraft
NH
EUR
17
(i) R/S TW (i) R/S TWQRH700 Impact
of R/S humidity
NH
EUR
18
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 (GUANGSN)
  • Additional R/S (TWind) and aircraft (TWind)
    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/S
  • R/S add forecast skill to Aircraft

19
EUCOS Space-Terrestrial, Conclusions (2)
  • 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

20
EUCOS Space-Terrestrial, Conclusions (3)
  • Humidity from R/S add very little in terms of
    scores
  • Noticeable 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)

21
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 GEOMODIS
  • 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)

22
2b Assessment of the space component of the
GOSInitiated and funded by EUMETSAT
  • Winter period 20061205-20070214 (31r1), Summer
    period 20060601-20060815 (31r2)
  • BASELINE all conventional observations used in
    NWP (radiosonde aircraft profiler network
    surface land data buoy observations ship
    data)
  • REFERENCE BASELINE AMSUA Noaa 16
  • REFERENCE AMVs from GEOMODIS
  • REFERENCE AMSUA radiances
  • REFERENCE AMSUB radiances
  • REFERENCE GEO Clear Sky Radiances (CSRs)
  • REFERENCE AIRS radiances
  • REFERENCE SCAT winds
  • CONTROL full operational system (all above
    observations)

23
Average Z 500 anomaly correlation scoresThe AMV
reference and the AMSU-A reference
S.Hem
N.Hem
All AMVs ref
All AMVs ref
S.Hem
N.Hem
One AMSUA_ ref
One AMSU_A ref
24
Z500 impacts, S.Hem (REFERENCE_AMV)
AMSU-B, SSMI, GEO_CSR
HIRS, AMSU-A, AIRS
Scat, GEO_AMV, GEO_CSR
25
Relative Humidity 850hPa impacts, S.Hem
(REFERENCE_AMV)
AMSU-B, SSMI, GEO_CSR
HIRS, AMSU-A, AIRS
Scat, GEO_AMV, GEO_CSR
26
Vector wind 200 hPa impacts, S.Hem
(REFERENCE_AMV)
AMSU-B, SSMI, GEO_CSR
HIRS, AMSU-A, AIRS
Scat, GEO_AMV, GEO_CSR
27
Impact of removing MODIS from the REFERENCE_AMV
28
500z amsu_a reference
29
Tropical Humidity amsu_a reference
30
Tropical Vector wind amsu_a reference
31
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.

32
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 2AMSU-A, 2
    DMSP, AIRS and IASI, ASCAT and QuikSCAT.
  • REFERENCE HIRS
  • REFERENCE AMSU
  • REFERENCE MHS
  • REFERENCE SOUNDERS
  • REFERENCE IASI
  • REFERENCE ASCAT
  • REFERENCE METOP

33
METOP forecast impact
500 hPa geopotential height RMS error difference
when METOP data withdrawn
T12 hours T24 hours
/100
34
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

35
GPS radio-occultation. Current 6-hour data
coverage.
36
December 2006 Assimilation of RO data at ECMWF
All 6 satellites
Wave-like bias disappeared
37
GPSRO impact on Southern hemisphere geopotential
height forecasts
6 COSMICsCHAMPGRACE-A (setting only, z gt 5 km)
no GPSRO 1100 observations/day, 66 cases,
winter 2006/2007, own analyses
1000 hPa 500 hPa
200 hPa 100 hPa
(Sean Healy)
38
GPSRO impact on Southern hemisphere geopotential
height forecasts
6 COSMICsCHAMPGRACE-A (settingrising, z gt 5
km) no GPSRO 1600 observations/day, 66 cases,
winter 2006/2007, own analyses
1000 hPa 500 hPa
200 hPa 100 hPa
(Sean Healy)
39
MetOP GRAS NH height scores
40
Metop GRAS SH height scores
41
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).

42
IASI forecast impact
500 hPa geopotential anomaly correlation (56
cases, spring 2007, normalized RMSE difference,
own analysis)
IASI better
NH
IASI worse
Mean error difference uncertainty
IASI better
SH
IASI worse
43
Choosing 10 IASI Water Vapour Channels
44
Fit to other observations
Best value at 1.5K
Normalized Analysis Departure Std. Dev.
Increasing assumed IASI H2O channels error
8
45
The Joint OSSE Nature Run
  • Collaboration 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

46
T511 Nature Run, 12-month total precipitation
47
Nature Run, 12-month total cloud cover
48
Nature Run, 12-month total cloud cover,
difference with respect to MODIS observations
49
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).

50
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
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