1 / 33

An overview of observation impact studies performed in the ALADIN community

An overview of observation impact studies performed in the ALADIN community. Claude Fischer; Zahra Sahlaoui, Fatima Hdiddou (DMN/Maroc); Roger Randriamampianina, Gergely Bölöni (Hun. Met. Serv.); Alena Trojáková (CHMI/Cz. Rep.); Marian Jurašek (SHMU/Slovakia);

emelda
Download Presentation

An overview of observation impact studies performed in the ALADIN community

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. An overview of observation impact studies performed in the ALADIN community Claude Fischer; Zahra Sahlaoui, Fatima Hdiddou (DMN/Maroc); Roger Randriamampianina, Gergely Bölöni (Hun. Met. Serv.); Alena Trojáková (CHMI/Cz. Rep.); Marian Jurašek (SHMU/Slovakia); Ludovic Auger, François Bouttier, Olivier Caumont, Véronique Ducrocq, Claudia Faccani, Thibaut Montmerle, Eric Wattrelot (Météo-France); Günther Haase (SMHI/Sweden) 4th WMO Workshop on the Impact of Various Observing Systems on NWP

  2. Overview • Some basic facts on ALADIN and AROME • Satellite observations for regional VAR: SEVIRI • EUCOS/PB-OBS experimentation • Radar data: • Wind • reflectivities • Sensitivity of « OSE’s » to other VAR ingredients • Outlook 4th WMO Workshop on the Impact of Various Observing Systems on NWP

  3. Some basic facts on the Aladin and Arome models • 3D-VAR (no FGAT) • Continuous assimilation cycles: • Aladin (6 hourly assim, coupled with Arpège, x=9.5km), • Arome (3 hourly assim, coupled with Ald-Fra, includes NH dynamics and sophisticated ,x=2.5km) • Observations: • Synop: surface pressure,T2m and RH2m (day), 10m winds • SHIP winds, drifting buoys • Aircraft data • SATOB AMV winds • Soundings (TEMP RS, PILOT, wind profilers) • Satellite radiances: NOAA and METOP (AMSU-A/B, MHS, HIRS), Meteosat-9 SEVIRI • scatterometer winds • Ground-based GPS zenital delays • Radar radial winds, radar reflectivity (via RH retrievals) 4th WMO Workshop on the Impact of Various Observing Systems on NWP

  4. ALADIN and AROME-France domains ALADIN-FRANCE AROME-FRANCE 4th WMO Workshop on the Impact of Various Observing Systems on NWP

  5. Satellite radiances for regional variational data assimilation • Impact study with ATOVS/AMSU-A in Aladin-NORAF (Morocco) • Impact of SEVIRI raw radiances in Aladin-France • Impact of SEVIRI raw radiances in Aladin-Hungary 4th WMO Workshop on the Impact of Various Observing Systems on NWP

  6. SEVIRI in Ald-Fra: data coverage as compared with other obs types ATOVS AMSU-B SEVIRI • Seviri data: • WV 6.2 and 7.3 m used in clear sky and over low clouds, as classified by the SAF-NWC cloud type product • IR 8.7, 10.8 and 12.0 m considered over the sea in cloud free regions only TEMP GPS 4th WMO Workshop on the Impact of Various Observing Systems on NWP

  7. Impact of radiances from polar orbiting v/s geostationary sat. Montmerle etal,, QJRMS, 2007 Sensitivity of the analysis (DFS) per obstypes OSEs: OPER: ALADIN/France oper moreATOVS: OPER with denser ATOVS data (AMSUA, AMSUB and HIRS) : 1 pixel/80 km vs. 1/250 km) noSEV: OPER without SEVIRI • OPER: about equal info. Content for TEMP / aircraft / SYNOP & SEVIRI • large increase of DFS for ATOVS data (especially AMSUB) for moreATOVS coupled with a decrease for SEVIRI: the influence of SEVIRI data in the analysis is reduced by the new information brought by extra ATOVS data • without SEVIRI data, DFS values for HIRS and AMSUB almost double 4th WMO Workshop on the Impact of Various Observing Systems on NWP

  8. Impact of SEVIRI radiances in Ald-Hungary • RMSE 90% significance test • Top: conv. Data + SEVIRI • Bottom: conv. Data + SEVIRI + SYNOP 2m T & RH 4th WMO Workshop on the Impact of Various Observing Systems on NWP

  9. Impact of SEVIRI radiances in Ald-Hun: RR for all thresholds and all fcst lead times 4th WMO Workshop on the Impact of Various Observing Systems on NWP

  10. Space-Terrestrial StudyEUCOS/PB-OBS seminar Domain of the ALADIN/HU model:12km, 37 levels, 48 h forecasts twice a day Roger RANDRIAMAMPIANINA Hungarian Meteorological Service, Budapest, Hungaryroger@met.hu Contributors:-Gergely BÖLÖNI, Sándor KERTÉSZ, Andrea LŐRINCZ and András HORÁNYI 4th WMO Workshop on the Impact of Various Observing Systems on NWP

  11. Example of QC (first guess check) - Active observations - Rejected observations 4th WMO Workshop on the Impact of Various Observing Systems on NWP

  12. Description of the experiments Winter/Summer EU01/ES01- baseline (GSN surface and GUAN radiosonde + AMV + ATOVS rad.)EU02/ES02- baseline + aircraftEU03/ES03- baseline + radiosonde windEU04/ES04- baseline + radiosonde wind and temperatureEU05/ES05- baseline + wind profilersEU06/ES06- baseline + radiosonde wind and temperature + aircraftEU07/ES07- baseline + radiosonde wind , temperature and humidityEU08/ES08- full observation (radiosonde + aircraft + wind profiler) 4th WMO Workshop on the Impact of Various Observing Systems on NWP

  13. Forecast evaluation: Impact of radiosonde wind observationTemperature T-850 Forecast evaluation: Impact of radiosonde temperature observationTemperature T-850 4th WMO Workshop on the Impact of Various Observing Systems on NWP

  14. Forecast evaluation: Impact of the radiosonde humidity 00 UTC 12 UTC BL + radiosonde T,V BL +radiosonde T,V,HU Full obs.RMSERR (mm/6h): comparison against surface measurements 4th WMO Workshop on the Impact of Various Observing Systems on NWP

  15. Overview of the most striking impacts: • Radiosonde: • Wind: positive impact in the troposphere over day 1 • T: positive impact over day 1; strong positive signal on MSLP for the summer period • RH: clear positive impact on MSLP in the winter period; large positive impact on RR at all fcst ranges • Aircraft AMDAR: • W/R to ECMWF analysis: clear positive signal on T, , FF, RH at all fcst ranges • Bigger impact in the summer period on all fields, up to 24 h • Positive impact on RH fcst in the summer, but negative impact for the winter period • Positive impact on RR fcst, mostly in the summer • AMDAR T/wind on top of RS T/wind: • Larger (positive) impact for the summer period, with an AMDAR extra effect about half of the one of RS 4th WMO Workshop on the Impact of Various Observing Systems on NWP

  16. Radar data assimilation • Doppler radial winds (Vr) • Reflectivities 4th WMO Workshop on the Impact of Various Observing Systems on NWP

  17. Vr: neutral to slightly positive scores in AROME-France RADAR CNTRL MSLP RR DD FF RH2m T2m R0 4th WMO Workshop on the Impact of Various Observing Systems on NWP

  18. Analysis of divergence at 950 hPa RADAR 01/12/07 18 UTC Guess RADAR CNTRL CNTRL 4th WMO Workshop on the Impact of Various Observing Systems on NWP

  19. Radar reflectivity assimilation Goal : Operationnally assimilate radar reflectivities in AROME by 2009-2010 Method : • Volumic (3D) reflectivity data routinely available at MF since August 2007, in real time. Pre-processing check to remove erroneous data (soil and sea clutters, …) • Reflectivity observation operator ready, simulates modelled reflectivities. • Quality control check by a gross comparison of observed and modelled columns. • Assimilation in the AROME system via a 1D+3DVar: reflectivities are inverted into pseudo-observations of relative humidity profiles (whose impact is expected to be bigger than when modifying the hydrometeor fields). 4th WMO Workshop on the Impact of Various Observing Systems on NWP

  20. Sensitivity of « OSE’s » to B matrix 850 hPa wind 0h Impact of using an interpolated B (here, vertical levels changed from 46 to 60) in the E-suite, W/r to using the genuine 60 level Recomputed ensemble fct stats (work of Abdelhak Razagui, ALG) MSLP 48h 850 hPa wind 12h Change of B matrix file: from the interpolated 46/60 to the genuine 60 level ensemble fct stats (Jan. 19th) 4th WMO Workshop on the Impact of Various Observing Systems on NWP

  21. Outlook • Future OSE’s: Arome on COPS period (South-West of Germany, July/August 2007) • New observations for LAM assimilations: • Microwave radiances over land • Radar data: 2008 (radial winds), 2009 or 2010 (reflectivities) • Cloud boguses ? • Combine upper-air analyses with a surface assimilation (simplified EKF) • Other R&D aspects • For optimized obs impact: one needs to work on all aspects of the assimilation system: B model, 4D-VAR ?, ensemble system simulation, filtering and spin-up, … • Common Aladin-Hirlam 4-year plan 4th WMO Workshop on the Impact of Various Observing Systems on NWP

  22. Thank you for your attention

  23. Impact study of NOAA/ATOVS raw radiances in Aladin/NORAF (Morocco) Impact of AMSU-A is positive over areas with a lack of observations (tropical band, Sahara, ocean) In mid latitudes, the impact of AMSU-A raw radiances is less marked (conflict between several observation types). More sensitivity studies are needed to optimise the use of raw radiances 4th WMO Workshop on the Impact of Various Observing Systems on NWP P30 humidity field at 850hPa level

  24. (DFS/nb of obs) ratio per obs type Montmerle et al, 2006 • For moreATOVS, DFS/p is slightly reduced for HIRS and AMSUB : using more data decreases the individual influence of one radiance in the analysis • This reduction is accentuated for AMSUA because of the broad structure functions that are used in the high troposphere/low stratosphere • For noSEV, the individual influence of one radiance is much higher than in OPER : This shows the complementarity of datasets that are sensitive to the same atmospheric component (very interesting for r6 and r18) 4th WMO Workshop on the Impact of Various Observing Systems on NWP

  25. Impact of aircraft (AMDAR) observations • Comparison against ECMWF analyses: a clear positive impact on the temperature, geopotential, wind speed and humidity fields was foundfor all the forecast ranges - Comparison against observations: the impact concerned mostly the analysis and forecasts up to 24-hour - A bigger positive impact of the aircraft observation was observed for the summer period than for the winter period- Positive impact of the aircraft data on the forecast of humidity fields was observed for the summer period, while negative impact was found for the winter period- Positive impact of the aircraft data on the forecast of precipitation was observed for the summer period, while neutral (from 00UTC) and negative (from 12 UTC) impact was observed for the winter period 4th WMO Workshop on the Impact of Various Observing Systems on NWP

  26. Impact of radiosonde observations • In the troposphere, clear positive impact of the radiosonde wind observation on the analysis and short-range forecasts was observed - A positive impact of the radiosonde temperature on the analysis and on the forecasts up to (mostly) 24-hours was observed - Clear positive impact of the radiosonde temperature data on the analysis and on the forecasts of the mean sea level pressure up to 24-hours was observed for the summer, while neutral impact was found for the winter period- Neutral impact of the radiosonde humidity on the mean sea level pressure was observed for the summer period, while clear positive impact was observed for the winter period- Bigger positive impact of the radiosonde temperature on the geopotential was observed in the summer study than for the winter study - Large positive impact of the radiosonde humidity was observed for all forecast ranges of precipitation 4th WMO Workshop on the Impact of Various Observing Systems on NWP

  27. Impact of AMDAR T/wind on top of RS T/wind - Comparing ES01, ES02 and ES04 (summer study), we found that the impact of the aircraft (wind & temp.) observations was a bit larger than what we found during the winter study (- half of that of the radiosonde (wind & temp.) data) - For the summer period, a small improvement in the scores was observed when comparing the impact of the aircraft data on top of the radiosonde windand temperature data (ES04 vs ES06), while a small deterioration was observed in the winter study 4th WMO Workshop on the Impact of Various Observing Systems on NWP

  28. 10m wind observations in ALADIN-France • ~2750 stations from synoptic network • Monitoring over 4 month data (September 2006 – December 2006) • Blacklisting when correlation between obs and model value < 0.3 => 101 stations blacklisted • Slight improvement with blacklisting • Experimental period : 01/09/2006-15/09/2006 • Good scores, especially in terms of sea-level pressure, tropospheric wind and tropospheric humidity RMS STDEV BIAS 4th WMO Workshop on the Impact of Various Observing Systems on NWP Comparison to pressure surface observation Scores to TEMP for wind force

  29. Elimination of non-Gaussian innovations ? • Test with removal of 600 stations (out of 2753) showing the less Gaussian aspect for innovations • Test based on good amount of population inside the 3 thresholds : s, 2s, 3s • No improvement, instead slight deterioration Bad station (PDF too Far from Gaussian profile) Good station RMS STDEV BIAS Deterioration of wind Scores compared with TEMP 4th WMO Workshop on the Impact of Various Observing Systems on NWP

  30. More pertinent assessment of the impact of radar data: One needs to go to QPF scores and fine-scale flow analysis (field of horizontal divergence) Severe wind situation on Northern France (early December 2007): non Doppler radars December 3rd, 00 UTC • area of interest is well covered with radar wind information 4th WMO Workshop on the Impact of Various Observing Systems on NWP

  31. A case with non-operating radars RADAR CNTRL QPF scores: A more difficult period for the radar experiment: Nov. 19th, 00 UTC -> Nov. 24th 00 UTC Precipitations over Eastern France Malfunctions at Bollène and St Nizier 4th WMO Workshop on the Impact of Various Observing Systems on NWP

  32. Monitoring of radar radial wind observations Example of 15 days for radars in Trappes, Abbeville, Falaise and Avesnes • Histograms: • Blue: total number of observations • Yellow: number of observations entering minimization • Red: number of elevations • Black: mean variance of Vr computed over slices of 10 deg. Site angle, per elevation 4th WMO Workshop on the Impact of Various Observing Systems on NWP

  33. Radar observation operator geometry implemented in the ALADIN/AROME 3D-VAR • Simulated Reflectivity factor in « beam volum bv» Antenna’s radiation pattern: gaussian function for main lobe (side lobes neglected) Resolution volum, ray path: standard refraction (4/3 Earth’s radius) model level N r j q z h • Bi-linear interpolation of the simulated hydrometeors (T,q, qr, qs, qg) • Compute « radar reflectivity » on each model level Diameter of particules Resolution volum, ray path : standard refraction (4/3 Earth’radius) Backscattering cross section: Rayleigh (attenuation neglected) Microphysic Scheme in AROME 4th WMO Workshop on the Impact of Various Observing Systems on NWP

More Related