Geneva, May st th WMO Workshop on the Impact of Various Observing Systems on NWP 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)

Geneva, May st th WMO Workshop on the Impact of Various Observing Systems on NWP Overview 1. Some basic facts on ALADIN and AROME 2. Satellite observations for regional VAR: SEVIRI 3. EUCOS/PB-OBS experimentation 4. Radar data: 1.Wind 2.reflectivities 5. Sensitivity of « OSE’s » to other VAR ingredients 6. Outlook

Geneva, May st th WMO Workshop on the Impact of Various Observing Systems on NWP 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)

Geneva, May st th WMO Workshop on the Impact of Various Observing Systems on NWP ALADIN and AROME-France domains ALADIN-FRANCE AROME-FRANCE

Geneva, May st th WMO Workshop on the Impact of Various Observing Systems on NWP 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

Geneva, May st th WMO Workshop on the Impact of Various Observing Systems on NWP TEMP GPS ATOVS AMSU-B SEVIRI Seviri data: WV 6.2 and 7.3  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  considered over the sea in cloud free regions only SEVIRI in Ald-Fra: data coverage as compared with other obs types

Geneva, May st th WMO Workshop on the Impact of Various Observing Systems on NWP Sensitivity of the analysis (DFS) per obstypes  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 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 Montmerle etal,, QJRMS, 2007 Impact of radiances from polar orbiting v/s geostationary sat.

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

Geneva, May st th WMO Workshop on the Impact of Various Observing Systems on NWP Impact of SEVIRI radiances in Ald-Hun: RR for all thresholds and all fcst lead times

Geneva, May st th WMO Workshop on the Impact of Various Observing Systems on NWP Roger RANDRIAMAMPIANINA Hungarian Meteorological Service, Budapest, Hungary Contributors: - Gergely BÖLÖNI, Sándor KERTÉSZ, Andrea LŐRINCZ and András HORÁNYI Space-Terrestrial Study EUCOS/PB-OBS seminar Domain of the ALADIN/HU model: 12km, 37 levels, 48 h forecasts twice a day Domain of the ALADIN/HU model: 12km, 37 levels, 48 h forecasts twice a day

Geneva, May st th WMO Workshop on the Impact of Various Observing Systems on NWP - Active observations - Active observations - Rejected observations - Rejected observations Example of QC (first guess check)

Geneva, May st th WMO Workshop on the Impact of Various Observing Systems on NWP Winter/Summer EU01/ES01- baseline (GSN surface and GUAN radiosonde + AMV + ATOVS rad.) EU02/ES02- baseline + aircraft EU03/ES03- baseline + radiosonde wind EU04/ES04- baseline + radiosonde wind and temperature EU05/ES05- baseline + wind profilers EU06/ES06- baseline + radiosonde wind and temperature + aircraft EU07/ES07- baseline + radiosonde wind, temperature and humidity EU08/ES08- full observation (radiosonde + aircraft + wind profiler) Description of the experiments

Geneva, May st th WMO Workshop on the Impact of Various Observing Systems on NWP Forecast evaluation: Impact of radiosonde wind observation Temperature T-850 Forecast evaluation: Impact of radiosonde temperature observation Temperature T-850

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

Geneva, May st th WMO Workshop on the Impact of Various Observing Systems on NWP 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

Geneva, May st th WMO Workshop on the Impact of Various Observing Systems on NWP Radar data assimilation ► Doppler radial winds (Vr) ► Reflectivities

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

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

Geneva, May st th WMO Workshop on the Impact of Various Observing Systems on NWP Goal : Operationnally assimilate radar reflectivities in AROME by 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). Radar reflectivity assimilation

Geneva, May st th WMO Workshop on the Impact of Various Observing Systems on NWP Sensitivity of « OSE’s » to B matrix MSLP 48h 850 hPa wind 0h 850 hPa wind 12h Change of B matrix file: from the interpolated 46/60 to the genuine 60 level ensemble fct stats (Jan. 19th) 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)

Geneva, May st th WMO Workshop on the Impact of Various Observing Systems on NWP 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

Thank you for your attention

Geneva, May st th WMO Workshop on the Impact of Various Observing Systems on NWP 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 P30 humidity field at 850hPa level Impact study of NOAA/ATOVS raw radiances in Aladin/NORAF (Morocco)

Geneva, May st th WMO Workshop on the Impact of Various Observing Systems on NWP  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) Montmerle et al, 2006 (DFS/nb of obs) ratio per obs type

Geneva, May st th WMO Workshop on the Impact of Various Observing Systems on NWP - Comparison against ECMWF analyses: a clear positive impact on the temperature, geopotential, wind speed and humidity fields was found for 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 Impact of aircraft (AMDAR) observations

Geneva, May st th WMO Workshop on the Impact of Various Observing Systems on NWP -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 observe d 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 Impact of radiosonde observations

Geneva, May st th WMO Workshop on the Impact of Various Observing Systems on NWP - 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 wind and temperature data (ES04 vs ES06), while a small deterioration was observed in the winter study Impact of AMDAR T/wind on top of RS T/wind

Geneva, May st th WMO Workshop on the Impact of Various Observing Systems on NWP 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 101 stations blacklisted ► Slight improvement with blacklisting ► Experimental period : 01/09/ /09/2006 ► Good scores, especially in terms of sea-level pressure, tropospheric wind and tropospheric humidity Comparison to pressure surface observationScores to TEMP for wind force RMS STDEV BIAS

Geneva, May st th WMO Workshop on the Impact of Various Observing Systems on NWP 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 :  2  3  ► No improvement, instead slight deterioration Deterioration of wind Scores compared with TEMP Bad station (PDF too Far from Gaussian profile) Good station RMS STDEV BIAS

Geneva, May st th WMO Workshop on the Impact of Various Observing Systems on NWP 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 More pertinent assessment of the impact of radar data:

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

Geneva, May st th WMO Workshop on the Impact of Various Observing Systems on NWP 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 Example of 15 days for radars in Trappes, Abbeville, Falaise and Avesnes Monitoring of radar radial wind observations

Geneva, May st th WMO Workshop on the Impact of Various Observing Systems on NWP Resolution volum, ray path : standard refraction (4/3 Earth’radius)   z h r N model level Bi-linear interpolation of the simulated hydrometeors (T,q, qr, qs, qg) Compute « radar reflectivity » on each model level Backscattering cross section: Rayleigh (attenuation neglected) Microphysic Scheme in AROME Diameter of particules 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) Radar observation operator geometry implemented in the ALADIN/AROME 3D-VAR