1. Impact of Blended MW-IR SST Analyses on NAVY Numerical Weather Prediction and Atmospheric Data Assimilation James Cummings, James Goerss, Nancy Baker Naval Research Laboratory Monterey, California MISST Project Review 28 November 2006 Washington, D.C.

2. SST and Sea Ice Analysis Navy Coupled Ocean Data Assimilation (NCODA) system assimilates all sources SST (satellite and in situ) and sea ice data Numerical Weather Prediction Navy Operational Global Atmospheric Prediction System (NOGAPS) NOGAPS SST and sea ice analysis directly on model T239 gaussian grid, 24-hour update cycle SST and sea ice LBC updated 6 times a day (real-time, off-time, post-time) Atmospheric Data Assimilation Navy Atmospheric Variational Data Assimilation System (NAVDAS) NAVDAS SST and sea ice analysis on global 9-km grid, 6-hour update cycle Hi-res SST analysis provides LBC for atmospheric sounding channels that “see” the surface NAVY SST Analysis and NWP

3. NCODA System Overview Sequential Incremental Update Cycle Analysis- Forecast-Analysis Ocean Model HYCOM Ocean QC 3D-MVOI (3D-Var) Ocean Obs SST: Ship (Bucket, ERI, Hull Contact), Buoy (Fixed, Drifting), AVHRR (GAC,LAC), GOES, AATSR, MSG, AMSR-E Temp/Salt Profiles: XBT, CTD, Buoy (Fixed, Drifting), Argo Floats, Gliders SSH: Altimeter, T/S profiles Sea Ice: SSM/I Innovations Increments Forecast Fields Prediction Errors First Guess SST QC includes background field check, diurnal warming check, and aerosol contamination check (NAAPS)

4. NOGAPS Assimilation Experiment 1 July – 30 September 2005 Control: AVHRR GAC in situ SST same in both runs Blended: AVHRR GAC and AMSR-E Observation Locations 30 Sep 2005 T239 gaussian grid 24 hour update cycle cold start from climatology AMSR-E and AVHRR GAC observation errors set to SSES AMSR-E bias corrected AMSR-E diurnal warming corrected AVHRR GAC diurnal warming event retrievals excluded

5. Analysis Verification 1 July - 30 Sep 2005 RMS residuals less than innovations; innovations and residuals unbiased RMS and mean bias statistics very similar between runs AMSR-E MW SST data doubled the number of observations in the analysis Control Blended

6. Analyzed SST Increments (C) 30 Sep 2005 Control Blended SST Background Error (C) Control Blended Background errors decreased in NW Pacific, NW Atlantic, Arabian Sea Background errors increased in Southern Ocean (Indian, Pacific, and Atlantic)

7. SST Observation Age (hours) 30 Sep 2005 Control Blended Control-Blended Observation Age Difference (hours) measure of time since grid point influenced by an observation takes into account observation errors and correlation structures positive age difference means AMSR-E data constrained SST field

8. Control 30 Sep 2005 Blended Fixed Buoy Fixed Buoy Drifting Buoy Drifting Buoy Innovation RMS, Bias ControlBlended Fixed Buoy0.73, 0.16 Drifting Buoy0.42, 0.030.48, 0.03 Blue – innovations Red - residuals

9. Control 30 Sep 2005 Blended AVHRR GAC AVHRR GAC AMSR-E Innovation RMS, Bias ControlBlended AVHRR GAC 0.48 -0.01 0.48 0.01 AMSR-E 0.44 -0.02 Blue – innovations Red - residuals

10. MISST Data Assimilation Experiment Current operational NOGAPS/NAVDAS data assimilation system run with operational FNMOC control SST analysis and with blended MISST analysis over the period from August 1- September 30, 2005. This was a particularly active period for tropical cyclones with 13 hurricanes (including Katrina and Rita), 9 typhoons, and 9 tropical storms. Both tropical cyclone forecast track error and 1000 mb and 500 mb geopotential height anomaly correlation were evaluated.

11. Impact Blended (MISST) IR and MW SST Analysis TC Forecast Error (nm) 318268220 Number of Forecasts 163111 August 1 - September 30, 2005

12. MISST Impact (Hurricanes Jova and Kenneth) TC Forecast Error (nm) 545046 Number of Forecasts 4238

13. MISST vs. Control Track Forecast Hurricane Rita - 00Z 22 September 2005

14. MISST Impact 500 mb Height Anomaly Correlation Northern HemisphereSouthern Hemisphere MISSTControl August 6 - September 30, 2005

15. MISST Impact 1000 mb Height Anomaly Correlation Northern HemisphereSouthern Hemisphere MISSTControl August 6 - September 30, 2005

16. Summary of Experimental Results The overall impact of the blended MISST analysis upon TC track forecast skill was neutral. However, the blended MISST analysis had significant positive impact upon the TC track forecasts for two long-lived storms (Jova and Kenneth) in the eastern North Pacific. The use of the blended MISST analysis resulted in a slight, but not significant, improvement in the 120-h 1000 mb and 500 mb geopotential height forecast anomaly correlation scores for the Northern Hemisphere. The use of the blended MISST analysis resulted in virtually no difference in the scores for the Southern Hemisphere or for the other forecast lengths in the Northern Hemisphere.

17. END