Report from DAOS-WG Presented by Richard Swinbank

1. Report from DAOS-WG Presented by Richard Swinbank Prepared by Roger Saunders with input from WG members

2. Current membership O=Observations D=Data Assimilation

3. DAOS-4 WG meeting Exeter 27-28 June 2011 • Review targetting paper • Updates on THORPEX campaigns • Review observing systems • Review developments in data assimilation • WG matters

4. Impact of different observation platforms from forecast sensitivity diagnostic METOP : MetOp ATOVS,MetOp IASI, MetOp ASCAT NOAA : NOAA15 ATOVS AMSUA, NOAA17 ATOVS HIRS, NOAA18 ATOVS, NOAA19 ATOVS OTHER LEO: EOS AIRS, F16 SSMIS, ERS, WINDSAT GEO : GOES, MTSAT, MSG Aircraft : AMDAR, AIREP SONDE : PILOT, TEMP SFC Land : SYNOP, BOGUS SFC Sea : BUOY,SHIP Total Impact = Number of soundings/profiles * mean observation Impact of each sounding/profile

5. The Concordiasi Project • Additional observations over Antarctica for NWP F. Rabier, V. Guidard, S. Noton-Haurot, A. Doerenbecher, D. Puech, • P. Brunel, A. Vincensini, H. Bénichou, Météo-France • Ph Cocquerez, CNES • Hertzog, F. Danis, IPSL/LMD • T. Hock, S. Cohn, J. Wang NCAR • C. Sahin, A. Garcia-Mendez, J-N Thépaut ECMWF • A. Cress, U. Pfluger, DWD • R. Langland, NRL • G. Verner, P. Koclas, CMC • R. Gelaro, NASA/GMAO • C. Parrett, R. Saunders Met Office • Y. Sato JMA

6. CONCORDIASIFlights overview Sept 2010-January 2011 2010, a stable Austral Winter Polar Vortex

7. 640 Dropsondes (20100923-20101201) Sea-Ice limit

8. Data Assimilation Monitoring Statistics over the Antarctic Radiosonde Background Temperature Departures (O-F) Obs Count Raob T RMS(O-F) Raob T Participants CMC DWD ECMWF GMAO Météo-France Met Office JMA Courtesy F. Rabier, Météo-France All models have difficulty predicting lowest-level temperatures

9. Concluding remarks on ConcordIASI • Concordiasi provided an unprecedented data coverage of meteorological observations over Antarctica • Both dropsonde and gondola information seem to have a positive impact on forecast performance (preliminary results from NRL, DWD and MF) • Gondola temperature data at 60hPa shows the largest model errors in areas of strong gravity-wave activity • Dropsonde information confirms statistics obtained with radiosondes and provide a more global view • Most models have problems predicting the lowest level temperatures

10. In –situ Measurements • Issues for THORPEX • Transition to BUFR for radiosondes provide new opportunities • GPS total zenith delay gobal coverage • In-situ soil moisture and temp • Common format for precip radar data • To improve estimates of solid precipitation and develop guidance on the accuracy and temporal resolution of solid precipitation parameters • New observations needed for mesoscale

11. Ground-based GPSObservations available from E-GVAP

12. Global Extent Radars now used to Verify NWP model Precipitation forecasts Need to advocate a common format worldwide to enable wider verification of precipitation ASSESS THE CURRENT AND POTENTIAL CAPABILITIES OF WEATHER RADARS FOR THE USE IN WMO INTEGRATED GLOBAL OBSERVERING SYSTEM (WIGOS ) by Ercan Büyükbaş, Turkish State Meteorological Service (TSMS)

13. Impact of NCEP Stage IV assimilation on 12h forecasts of precipitation. Sept-Oct 2009 average (CY35R2; T511 L91) NCEP Stage IV obs (mm/day) CTRL – NCEP Stage IV  Mean bias and RMS error are reduced NEW – NCEP Stage IV ECMWF 2011

14. Direct 4D-Var assimilation of NCEP Stage IV rain data ECMWF 2011 Impact on forecast scores for other parameters (Z, T, wind, RH): - neutral or slightly positive impact on the global scale. - some hint of positive impact over Europe (days 4-5) and Asia (days 8-10). RMSE North. Hemis. 500hPa wind RMSE Europe 500hPa temperature Forecast Root Mean Square Error changes due to direct 4D-Var assimilation of NCEP Stage IV rain data 1 April – 6 June 2010, T1279 (~15 km global) L91 good RMSE South. Hemis. 500hPa wind RMSE Asia 850hPa Temperature

15. Satellite Measurements • Issues for THORPEX • Extended life of some research satellites helps to mitigate losses elsewhere • Reduced thinning of AMSU-A shown to beneficial • Hyperspectral sounder in GEO orbit now approved by Europe on MTG • Contribution to GOS by nations increasing (e.g. FY-3, Oceansat-2) to fill future gaps in GOS • Challenge of assimilation of satellite data in high resolution local area models and extend use of advanced IR sounders (cloudy rads, use PCs,..)

16. Importance of Scatterometer winds • ASCAT winds for Irene and model background • Only one scat now used for NWP • Trials using scatterometer on Oceansat-2

18. The targeting procedure A. Doerenbecher, Météo France

19. Impact of dropsonde data for Irene

20. Comparison of different models Tropical cyclone track forecast errors during the Summer T-PARC period for four assimilation-forecast systems. The solid (dashed) lines represent parallel analysis-forecast cycles excluding (including) T-PARC dropwindsonde data.

21. DAOS-WG Statement on impact of targeted data • For mid-latitude systems, the value of targeted data is found to be positive but small on average. The WSR programme has found that targeting results in some improvement in 2-3 day forecasts over N. America. • Observations in dynamically sensitive areas have a bigger average impact per observation than those deployed randomly. The cumulative benefit of a small number of targeted aircraft observations to forecast accuracy over broad verification regions is smaller than that of other observing systems that provide observations with a more complete coverage. • For forecasts of the track of TCs targeted observations have proven to be beneficial statistically. A simple sampling strategy of observing uniformly around the TC has been shown to be effective, with most models exhibiting an improvement. • There is a need to assess the impact of targeted observations with more user-focused measures of the value of forecast improvements to society, while retaining the ability to get significant results from relatively short experiments.

22. DAOS-WG Future Directions • Maintain links with ET-EGOS, WGNE, etc • Next meeting in Madison 19-20 Sep 2012 • Joint meeting with MFWR under discussion • DAOS remains a global focus not mesoscale • Continue mix of Observations and DA • Leading group for DA in WMO together with WGNE. What is future post THORPEX?