A summary of OSE and OSSE activities at

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 t Three major sets of OSEs t Investigating the complementarity between space based and terrestrial observing systems t The impact of Met. OP instruments t Impact of GPS Radio Occultation data t The Joint-OSSE, followed by Conclusions WMO Workshop 19 -21 May 2008: ECMWF OSEs Slide 1 ECMWF

1: The Space-Terrestrial Study Initiated 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) WMO Workshop 19 -21 May 2008: ECMWF OSEs Slide 2 ECMWF

OSE assimilation system configuration t Resolutions: t Model resolution T 511 (50 km), L 60 t Analysis at T 511/T 159 L 60, t 12 -hour 4 D-Var t Winter Experiments: t 20041204 -00 to 20050125 -12 (including 10 day warm up) t Model cycle 29 R 1 t Summer experiments: t 20050715 -00 to 20050915 -12 (including 10 day warm up) t Model cycle 29 R 2 t NOAA 18 included (AMSU-A and MHS) WMO Workshop 19 -21 May 2008: ECMWF OSEs Slide 3 ECMWF

Winter results: Baseline – Control (Z 500) Impact of terrestrial, non-climate, observations NH EUR WMO Workshop 19 -21 May 2008: ECMWF OSEs Slide 4 ECMWF

Control-Baseline (Z 500) Normalised forecast error difference, Day-3 WMO Workshop 19 -21 May 2008: ECMWF OSEs Slide 5 ECMWF

Z scores: Impact of R/S 1000 h. Pa 500 h. Pa NH EUR WMO Workshop 19 -21 May 2008: ECMWF OSEs Slide 6 ECMWF

Baseline – [ Baseline + aircraft] Z 500 Impact of aircraft data NH EUR WMO Workshop 19 -21 May 2008: ECMWF OSEs Slide 9 ECMWF

[Baseline + aircraft] - Baseline (Z 500) Normalised forecast error difference FC+12 h WMO Workshop 19 -21 May 2008: ECMWF OSEs Slide 10 ECMWF

Z scores: Impact of aircraft 1000 h. Pa 500 h. Pa NH EUR WMO Workshop 19 -21 May 2008: ECMWF OSEs Slide 11 ECMWF

Wind scores: Impact of aircraft 850 h. Pa 300 h. Pa NH EUR WMO Workshop 19 -21 May 2008: ECMWF OSEs Slide 12 ECMWF

[(i) + R/S T+W] – [ (i) + R/S T+W + aircraft] Z 500 Impact of aircraft in the presence of R/S NH EUR WMO Workshop 19 -21 May 2008: ECMWF OSEs Slide 13 ECMWF

[(i) + R/S T+W + aircraft] – [(i) + R/S T+W] (Z 500) Z 500 Impact of aircraft in the presence of R/S WMO Workshop 19 -21 May 2008: ECMWF OSEs Slide 14 ECMWF

[(i) + R/S T+W] – [ (i) + R/S T+W + aircraft] W 300 Impact of aircraft in the presence of R/S NH EUR WMO Workshop 19 -21 May 2008: ECMWF OSEs Slide 15 ECMWF

[(i) + aircraft] – [ (i) + R/S T+W + aircraft] W 300 Impact of R/S in the presence of aircraft NH EUR WMO Workshop 19 -21 May 2008: ECMWF OSEs Slide 16 ECMWF

[(i) + R/S T+W] – [ (i) + R/S T+W+Q] RH 700 Impact of R/S humidity NH EUR WMO Workshop 19 -21 May 2008: ECMWF OSEs Slide 17 ECMWF

EUCOS Space-Terrestrial, Conclusions (1) t Even in presence of satellite observations, degrading the current terrestrial Observing System has a significant negative impact on the forecast skill. t Starting from the degraded baseline (GUAN+GSN+…): t Additional R/S (T+Wind) and aircraft (T+Wind) contribute more or less equally to the Observing System (slight advantage for R/S) t These two Observing Systems are complementary èAircraft add forecast skill to R/S èR/S add forecast skill to Aircraft WMO Workshop 19 -21 May 2008: ECMWF OSEs Slide 18 ECMWF

EUCOS Space-Terrestrial, Conclusions (2) t R/S impact: t R/S winds contribute little on their own t Radiosonde T contribute marginally more t This is the combination of wind/T which really provides the impact of the RS on the forecast skill t Aircraft impact: t The results are consistent with that of R/S. Aircraft-T alone bring relatively little. Combination of T/Wind makes a big impact WMO Workshop 19 -21 May 2008: ECMWF OSEs Slide 19 ECMWF

EUCOS Space-Terrestrial, Conclusions (3) t Humidity from R/S add very little in terms of scores t Noticeable but small impact on relative humidity scores up to day 3 t Impact of wind profilers: t Winter impact: è The short range forecasts are improved by the US and japanese profilers è The signal blurs away after day 4 -5 and large scale interactions appear è European profilers do not bring much t In summer, the impact is smaller than during the winter period (in absolute but also relative terms) WMO Workshop 19 -21 May 2008: ECMWF OSEs Slide 20 ECMWF

2 a: Assessment of the space component of the GOS Initiated and funded by EUMETSAT Winter period: 20041204 -20050125, Summer period: 20050715 -20050915 (cycle 29 r 1) t BASELINE all conventional observations used in NWP (radiosonde + aircraft + profiler network + surface land data + buoy observations + ship data) t REFERENCE= BASELINE + AMVs from GEO+MODIS t REFERENCE + HIRS radiances t REFERENCE + AMSUA radiances t REFERENCE + AMSUB radiances t REFERENCE + SSMI radiances t REFERENCE + GEO Clear Sky Radiances (CSRs) t REFERENCE + AIRS radiances t REFERENCE + SCAT winds t BASELINE + GEO AMVs (no MODIS) WMO Workshop 19 -21 May 2008: ECMWF OSEs Slide 21 ECMWF

2 b: Assessment of the space component of the GOS Initiated and funded by EUMETSAT Winter period: 20061205 -20070214 (31 r 1), Summer period: 20060601 -20060815 (31 r 2) i. iii. iv. v. viii. ix. 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 GEO+MODIS 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) WMO Workshop 19 -21 May 2008: ECMWF OSEs Slide 22 ECMWF

Average Z 500 anomaly correlation scores The AMV reference and the AMSU-A reference S. Hem All AMVs ref S. Hem One AMSU_A ref WMO Workshop 19 -21 May 2008: ECMWF OSEs N. Hem All AMVs ref N. Hem One AMSUA_ ref Slide 23 ECMWF

Z 500 impacts, S. Hem (REFERENCE_AMV) AMSU-B, SSMI, GEO_CSR HIRS, AMSU-A, AIRS Scat, GEO_AMV, GEO_CSR WMO Workshop 19 -21 May 2008: ECMWF OSEs Slide 24 ECMWF

Relative Humidity 850 h. Pa impacts, S. Hem (REFERENCE_AMV) AMSU-B, SSMI, GEO_CSR HIRS, AMSU-A, AIRS Scat, GEO_AMV, GEO_CSR WMO Workshop 19 -21 May 2008: ECMWF OSEs Slide 25 ECMWF

Vector wind 200 h. Pa impacts, S. Hem (REFERENCE_AMV) AMSU-B, SSMI, GEO_CSR HIRS, AMSU-A, AIRS Scat, GEO_AMV, GEO_CSR WMO Workshop 19 -21 May 2008: ECMWF OSEs Slide 26 ECMWF

Impact of removing MODIS from the REFERENCE_AMV WMO Workshop 19 -21 May 2008: ECMWF OSEs Slide 27 ECMWF

Space component, Summary t 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. t The humidity analysis requires AMSUB (also MHS), GEO CSRs and SSMI. t 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. WMO Workshop 19 -21 May 2008: ECMWF OSEs Slide 31 ECMWF

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. t REFERENCE: All conventional data + 2*AMSU-A, 2* DMSP, AIRS and IASI, ASCAT and Quik. SCAT. t REFERENCE – HIRS t REFERENCE – AMSU t REFERENCE – MHS t REFERENCE – SOUNDERS t REFERENCE – IASI t REFERENCE – ASCAT t REFERENCE – METOP WMO Workshop 19 -21 May 2008: ECMWF OSEs Slide 32 ECMWF

METOP forecast impact 500 h. Pa geopotential height RMS error difference when METOP data withdrawn T+12 hours T+24 hours [%/100] WMO Workshop 19 -21 May 2008: ECMWF OSEs Slide 33 ECMWF

Preliminary results on Metop (ongoing study) t The fit to temperature-sounding instruments (e. g. NOAA 18 AMSU-A) is improved when Metop instruments are present. t The fit to moisture-sounding instruments (e. g. AIRS, MHS, GOES) is improved when Metop MHS, all Metop sounders or IASI are present t The presence of ASCAT data slightly improves the fit to Quik. SCAT wind data, and products from Envisat and Jason altimeters t The synergy of Metop instruments produces a much stronger impact than its individual instruments WMO Workshop 19 -21 May 2008: ECMWF OSEs Slide 34 ECMWF

GPS radio-occultation. Current 6 -hour data coverage. WMO Workshop 19 -21 May 2008: ECMWF OSEs Slide 35 ECMWF

December 2006: Assimilation of RO data at ECMWF All 6 satellites Wave-like bias disappeared WMO Workshop 19 -21 May 2008: ECMWF OSEs Slide 36 ECMWF

GPSRO impact on Southern hemisphere geopotential height forecasts 6 COSMICs+CHAMP+GRACE-A (setting only, z > 5 km) – no GPSRO 1100 observations/day, 66 cases, winter 2006/2007, own analyses 1000 h. Pa 500 h. Pa 200 h. Pa 100 h. Pa (Sean Healy) WMO Workshop 19 -21 May 2008: ECMWF OSEs Slide 37 ECMWF

200 h. Pa 100 h. Pa 500 h. Pa 6 COSMICs+CHAMP+GRACE-A (setting+rising, z > 5 km) – no GPSR 1600 observations/day, 66 cases, winter 2006/2007, own analyses SRO impact on Southern hemisphere geopotential height for ECMWF Slide 38 WMO Workshop 19 -21 May 2008: ECMWF OSEs

Advanced infrared sounders: AIRS and IASI AIRS t Operational at ECMWF since October 2003. t 324 channels received in NRT. t One FOV in nine used. t Up to 155 channels may be assimilated (CO 2 and H 2 O bands). IASI t Operational at ECMWF since June 2007. t 8461 channels received in NRT. t All FOVS received; only 1 -in-4 used. t 366 Channels routinely monitored. t Up to 168 channels may be assimilated (CO 2 band only). WMO Workshop 19 -21 May 2008: ECMWF OSEs Slide 41 ECMWF

IASI forecast impact 500 h. Pa geopotential anomaly correlation (56 cases, spring 2007, normalized RMSE difference, own analysis) IASI better IASI worse NH Mean error difference uncertainty IASI better IASI worse SH WMO Workshop 19 -21 May 2008: ECMWF OSEs Slide 42 ECMWF

Choosing 10 IASI Water Vapour Channels WMO Workshop 19 -21 May 2008: ECMWF OSEs Slide 43 ECMWF

Normalized Analysis Departure Std. Dev. Fit to other observations Best value at 1. 5 K WMO Workshop 19 -21 May 2008: ECMWF OSEs Increasing assumed IASI H 2 O channels’ error Slide 44 ∞ ECMWF

The Joint OSSE Nature Run t 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 t T 511 NR: 13 months T 511/L 91. t Data set size ~2. 5 Tbyte. Shipping to the US on 4 disks t Yearly, quarterly and monthly comparison with climate and observations = 831 plots. Posted on NCEP web site t Extensive evaluation of the NR by US partners t T 799 NR: Two 6 -week periods have been run at T 799/L 91 with hourly post processing: TC-season, Convective season WMO Workshop 19 -21 May 2008: ECMWF OSEs Slide 45 ECMWF

Nature Run, 12 -month total cloud cover WMO Workshop 19 -21 May 2008: ECMWF OSEs Slide 47 ECMWF

Nature Run, 12 -month total cloud cover, difference with respect to MODIS observations WMO Workshop 19 -21 May 2008: ECMWF OSEs Slide 48 ECMWF

Comparison of extra-tropical cyclones in the NR against cyclones in the NCEP analyses for 5 recent years (green bars), showing central pressure (h. Pa, left) and life span (days, right panel). Courtesy Joe Terry (NASA). WMO Workshop 19 -21 May 2008: ECMWF OSEs Slide 49 ECMWF

OSEs and OSSE activities at ECMWF Conclusions t Space-terrestrial study (EUCOS) completed t Assessment of space-component of the GOS (EUMETSAT) completed t Assessment of Metop impact (EUMETSAT) is ongoing t Comprehensive reports are available t ECMWF Newsletter No 113, page 16 -28 (Kelly and Thépaut) t Metop-IASI and GPS-RO constitute significant new additions to the GOS t Joint-OSSE framework being developed, attracting a lot of interest, generating wide-spread collaboration WMO Workshop 19 -21 May 2008: ECMWF OSEs Slide 50 ECMWF