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Data Impact Experiments at the JCSDA and NCEP/EMC

Data Impact Experiments at the JCSDA and NCEP/EMC. S. Lord (NCEP/EMC) L.P. Riishojgaard (JCSDA) Contributions by: L. Cucurull, J. Jung, L. Bi, D. Kleist, B. Yan, I. Appel, D. Stokes. Overview. Impact experiments for: COSMIC QuikSCAT & Windsat MODIS winds IASI SSM/IS ASCAT

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Data Impact Experiments at the JCSDA and NCEP/EMC

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  1. Data Impact Experimentsat the JCSDA and NCEP/EMC S. Lord (NCEP/EMC) L.P. Riishojgaard (JCSDA) Contributions by: L. Cucurull, J. Jung, L. Bi, D. Kleist, B. Yan, I. Appel, D. Stokes

  2. Overview • Impact experiments for: • COSMIC • QuikSCAT & Windsat • MODIS winds • IASI • SSM/IS • ASCAT • Summary and comments

  3. COSMIC Data Impact Tropics 200 hPa RMS Wind Error 48 h 0.1 m/s improvement • No COSMIC • With COSMIC • 1 Nov 2006 to 30 Nov 2006 • Refractivity assimilated variable • ~1000 profiles assimilated per day NH 500 hPa Height Anom. Cor. SH 500 hPa Height Anom. Cor. L. Cucurull

  4. QuikSCAT Impact on Standard Verification Scores • Operational GFS (T382/L64), GSI with FOTO • Control (operational QuikSCAT) • Q denial (no QuikSCAT) • Q new (FY07 improved retrievals) • 5 July 2005 25 to October 2005 (~4 months) D. Kleist NH 1000 hPa Height RMS Error SH 1000 hPa Height RMS Error Similar results obtained for 2006 cases

  5. Windsat Impact on Standard Verification Scores • Operational GFS (T382/L64), GSI with FOTO • Control (operational QuikSCAT) • Ws included (with QuikSCAT) • Ws only (no QuikSCAT) • No Ws, no Qs • 25 April 2007 to 8 June 2007 (~1.5 months) D. Kleist NH 1000 hPa Height RMS Error SH 1000 hPa Height RMS Error

  6. QuikSCAT Impact on Tropical Cyclone Forecasts2004 Study Jung and Zapotocny JCSDA

  7. QuikSCAT Impact on Tropical Cyclone Forecasts (cont) Track Error Atlantic 2005 00&12 UTC Track Error Atlantic 2005 00&12 UTC Climatology-persistence No QuikSCAT New QuikSCAT D. Kleist D. Stokes 65 cases 18 cases

  8. Impact of MODIS winds on GFS500 hPa Anomaly Correlation NH July NH February SH February SH July I. Appel

  9. IASI Impact Tests • First attempt to use data at JCSDA/NCEP(EMC) • Channel selection: EUMETSAT longwave only • 30 day spinup for bias correction • Experiment and control use same initial bias corrections • Scores averaged over last 30 days • 1-31 August 2007 • 16 December 2007 -15 January 2008

  10. IASI Impact on Standard Verification Scores 1-31 August 2007 NH 500 hPa Height Anom. Cor. SH 500 hPa Height Anom. Cor. IASI Control J. Jung

  11. IASI Impact on Standard Verification Scores 16 December 2007 - 15 December 2008 NH 500 hPa Height Anom. Cor. SH 500 hPa Height Anom. Cor. IASI Control J. Jung

  12. SSM/IS Impact Summary • Positive impacts of SSMIS UPP data can be obtained through improved cloud detection, surface snow and sea ice emissivity simulations • A positive impact of SSMIS UPP data is anticipated by addingwater vapor channels (not shown) • The SSMIS UPP data displays some regionally dependent biases at several sounding channels which would reduce their assimilation impact (not shown)

  13. Improved SSM/IS forecast impact due to science & processing upgrades Improved cloud detection & QC Improved snow and sea ice emissivity Alternate processing CTL Cloud detection & QC EXP EXP CTL B. Yan et al

  14. ASCAT Impact Tests • First results at JCSDA/NCEP(EMC) • 10 December 2007 – 19 January 2008 • Thinned to 100 km • Quality Control: • Ocean only (from GDAS land-sea flag) • Reject observation if O-B > 5m/s (U and V) Li Bi & J. Jung NH 1000 hPa Height Anom. Cor. SH 1000 hPa Height Anom. Cor. ASCAT Control

  15. ASCAT Impact Tests • First results at JCSDA/NCEP(EMC) • 10 July 2007 – 17 August 200 • Thinned to 100 km • Quality Control: • Ocean only (from GDAS land-sea flag) • Reject observation if O-B > 5m/s (U and V) Li Bi & J. Jung NH 1000 hPa Height Anom. Cor. SH 1000 hPa Height Anom. Cor. ASCAT Control

  16. Summary & Comments • Impacts measures by standard scores for • COSMIC • QuikSCAT & Windsat • MODIS winds • IASI • SSM/IS • ASCAT • JCSDA and NCEP experience • Spin up of global system takes ~6 weeks to produce reliable obs. sensitivity signal • Coarse resolution results not representative of those at resolutions higher than ~50 km globally • Use of downstream models and applications could be useful to determine impacts • Hurricanes • Waves • Impact depends on improvements to science (e.g. SSM/IS) • Surface emissivity (MW and IR) • Bias correction • Cloud detection

  17. Summary & Comments(cont) • Impact experiments are resource intensive • Many take place in the course of the operational implementation process and are necessary • Many custom experiments generally beyond our means • Respond to HQ requests for special programs (e.g. QuikSCAT) • Could (and should) be done annually with proper support (e.g. instrument programs) • Would pay dividends in • Focusing scientific development • Providing feedback for future instrument programs • Keeping entire community engaged in the total investment • A complementary OSSE program would be a very useful addition

  18. Backup Slides

  19. SATELLITE DATA STATUS – May 2008

  20. Jung and Zapotocny JCSDA Funded by NPOESS IPO Satellite data ~ 10-15% impact

  21. Operational data assimilation at NCEP Lidia Cucurull Joint Center for Satellite Data Assimilation COSMIC IWG Meeting, New Orleans, LA, Jan 21 2008.

  22. Achievements at the JCSDA • The JCSDA developed, tested and incorporated into the new generation of NCEP’s Global Data Assimilation System the necessary components to assimilate two different type of GPS RO observations (refractivity and bending angle). These components include: • complex forward models to simulate the observations (refractivity and bending angles) from analysis variables and associated tangent linear and adjoint models • Quality control algorithms & error characterization models • Data handling and decoding procedures • Verification and impact evaluation algorithms • Pre-operational implementation runs showed a positive impact in model skill when COSMIC profiles were assimilated on top of the conventional/satellite observations. • As a result, COSMIC became operationally assimilated at NCEP on May 1st 2007, along with the implementation of the new NCEP’s Global Data Assimilation System (GSI/GFS). [Profiles of refractivity were selected for implementation in operations, while the tuning of the assimilation of bending angles is currently being analyzed at NCEP]. • The assimilation of observations from the COSMIC mission into the NCEP’s operational system has been a significant achievement of the JCSDA. [Operational assimilation one year after launch!].

  23. Characteristics of COSMIC observations • Limb sounding geometry complementary to ground and space nadir viewing instruments • High vertical resolution (0.1 km surface - 1km tropopause) • Lower horizontal resolution (~300 km) • All weather-minimally affected by aerosols, clouds or precipitation • High accuracy (equivalent to < 1 Kelvin from 5-25 km) • Equivalent accuracy over ocean than over land • Independent of radiosonde calibration • No instrument drift • Global coverage • No satellite-to-satellite observational bias • Inexpensive compared to other sensors

  24. Characteristics of COSMIC observations • We assimilate rising and setting occultations, there is no black-listing of the low-level observations (provided they pass the quality control checks), and we do not assimilate observations above 30 km (due to model limitations). • In an occultation, the drift of the tangent point is considered. Average COSMIC counts/day at NCEP (2007) The remaining ~30% received, but not assimilated, is due to: • Preliminary quality control checks (bad data/format) • Gross error check (obs very different from the model) • Statistics quality control check (obs too different from the model-obs statistics)

  25. Pre-operational implementation run • PRYnc (assimilation of operational obs ), • PRYc (PRYnc + COSMIC refractivity) • We assimilated around 1,000 COSMIC profiles per day rms error (wind) Anomaly correlation as a function of forecast day (geopotential height)

  26. Pre-operational implementation run (cont) • Dashed lines: PRYnc • Solid lines: PRYc (with COSMIC) • Red: 6-hour forecast • Black: analysis

  27. Summary and future plans • COSMIC (refractivity) became operationally assimilated at NCEP on May 1st 2007, along with the implementation of the new NCEP’s Global Data Assimilation System (GSI/GFS). • Several impact studies for selected periods show a positive impact in model skill when COSMIC profiles are assimilated on top of the conventional/satellite observations. [We have recently improved the assimilation of GPSRO profiles over complex topography.] what is next? • Testing, tuning and assimilation of GSPRO from CHAMP & GRACE (in pre-operational mode; March 2008) and MetOp/A GRAS (when available). • Setup the monitoring of GPSRO statistics in operations (May 2008). • Update QC checks and obs error for COSMIC data (June 2008). • Assimilation of COSMIC observations (and other GPSRO missions) into the regional model (July 2008). • Improve the performance of the assimilation of observations of bending angle (November 2008; switch to bending angle in operations?). • Explore more complex forward operators to take into account horizontal gradients of refractivity (??).

  28. Time series of day-5 scores

  29. Five-day forecast minus verifying analysis. February 23, 2007, 00z Control Control + MODIS IR

  30. Impact of Improved Snow and Sea Ice Emissivity at SSMIS Channels on F16 UPP SSMIS Data Usage More data is assimilated Into GFS ! New SNOW EM New Ice EM Old EM

  31. (July 1 ~ July 10, 2007) A positive impact of SSMIS UPP data at water vapor sounding channels is detected on GFS.

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