Global RTOFS Upgrade and Metrics at the GODAE Annual Science Team Meeting

1. Update on NOAA IV-TT Activity Todd Spindler1, Avichal Mehra2,Ilya Rivin1 1IMSG at NWS/NCEP/EMC 2NWS/NCEP/EMC 1 1 6-10 November 2017 GODAE Annual Science Team meeting (GOVST-VIII) , Bergen, Norway

2. Outline • Description of upgraded Global RTOFS • Overview of Metrics • Examples from Production Suite including production-parallel evaluations • Notes on EMC Reorganization and Future Plans • Summary 2 6-10 November 2017 GODAE Annual Science Team meeting (GOVST-VIII) , Bergen, Norway

3. Global RTOFS • Global RTOFS is the first global eddy-resolving ocean forecast system at NOAA/NCEP implemented in close collaboration with the US Navy. • This global system is based on a 1/12 degree HYCOM (HYbrid Coordinate Ocean Model) developed by the US Navy with a Pan-Am Global Grid (4500 x 3928). • The system has 41 vertical hybrid layers (isopycnal in the deep, isolevel in the mixed layer and sigma in shallow waters). • The initialization is based on a daily live feed of analysis fields provided by NAVOCEANO from a 3DVar data assimilation scheme (NCODA) developed by the US Navy which assimilates daily observations (T, S, U, V and SSH) in a sequential incremental update cycle. • The daily global ocean forecasts at NCEP are forced with the GFS surface fluxes of radiation, precipitation and momentum. • Strong collaboration with US Navy, leveraging core HYCOM and data assimilation developments at NRL. 3 6-10 November 2017 GODAE Annual Science Team meeting (GOVST-VIII) , Bergen, Norway

4. 1/12 Degree Global Domain Primary Users: NWS:EMC,OPC,NHC, WFO/NWPS NOS: CO-OPS, CSDL. IOOS OAR: OWAQ, AOML/HRD US Coast Guard Primary research partners: NRL, ESRL, STAR, NESDIS, JCSDA, JAEA (Japan), UMD, FSU, MSU 4 6-10 November 2017 GODAE Annual Science Team meeting (GOVST-VIII) , Bergen, Norway

5. RTOFS Global Upgrade • Upgraded model went operational 16 October 2017. • Increases the number of vertical layers from 32 to 41 hybrid layers with additional iso-level coordinate layers in the upper ~200m. • Global RTOFS is now coupled with Los Alamos National Laboratory’s Community Sea Ice (CICE) model using v4.0 of Earth System Modeling Framework (ESMF). • Updated bathymetry, which improves representation of grid points in shallow regions where minimum depth is set to 5m. • Updated Equation of State from 9 terms to 17 terms. 5 6-10 November 2017 GODAE Annual Science Team meeting (GOVST-VIII) , Bergen, Norway

6. NCEP Production Metrics Suite • Monitoring of daily model runs using GODAE Class Metrics (Le Provost et al., 2002, Fernandez et al., 2009) • Class-1 (analysis of fields on pre-defined grids e.g. SST, SSH, Sea Ice Cover) • Class-2 (vertical sections, e.g, WOCE sections) • Class-3 (derived products, e.g. Florida Current transports, GS North Wall location) • Class-4 (forecast skill on observed grids: SST, SSH, profiles) • Daily/Weekly monitoring metrics/stats are available at: http://polar.ncep.noaa.gov/global/class-4 (userid: RTOFSEVAL password: EVAL2007) 6 6-10 November 2017 GODAE Annual Science Team meeting (GOVST-VIII) , Bergen, Norway

7. Class-1: Sea Ice Cover NCEP Sea Ice Analysis Antarctic Arctic While both parallel and production model mean ice cover areas overlap their std deviations, parallel ice coverage appears to be slightly better in the Arctic. 7 6-10 November 2017 GODAE Annual Science Team meeting (GOVST-VIII) , Bergen, Norway

8. Class-2: WOCE Sections • 48 Tracks worldwide • RTOFS sections computed daily • Colormaps calibrated against eWOCE graphics • Nowcast only Analysis available at http://polar.ncep.noaa.gov/global/woce 8 20 September 2016 GODAE OceanView IV/TT Workshop, Montreal, Canada

9. Class-2: WOCE Sections Track A16 Potential Temperature Salinity WOCE RTOFS 9 6-10 November 2017 GODAE Annual Science Team meeting (GOVST-VIII) , Bergen, Norway

10. Class-3: Florida Cable Transports • Since 1982, submarine cables have been used to measure the transport of the Florida Current between Florida and the Bahamas near 27°N. • RTOFS transport computed daily and compared with observations. • Weekly means and correlations computed 10 6-10 November 2017 GODAE Annual Science Team meeting (GOVST-VIII) , Bergen, Norway

11. Class-3: Florida Cable Transports PRODUCTION PARALLEL Parallel model shows overall better agreement with obs than production model, with generally higher correlations 11 6-10 November 2017 GODAE Annual Science Team meeting (GOVST-VIII) , Bergen, Norway

12. Class-3: Gulf Stream & Loop Current Locations METRIC PRODUCTION PARALLEL The Global RTOFS Gulf Stream and Loop Current location is defined as the intersection of the 12°C isotherm and the 400m isobath (Halkin and Rossby, 1985). Metric is comparison of RTOFS location against NAVOCEANO frontal analysis. Method uses Modified Hausdorff (M. P. Dubuisson and A. K. Jain (1994)). Metric is only computed if Navy analysis is available. 12 6-10 November 2017 GODAE Annual Science Team meeting (GOVST-VIII) , Bergen, Norway

13. Class-4: SSH SSALTO/DUACS - MRT MADT Merged Product Global Gulf of Mexico Daily comparison between Global RTOFS and MADT (SSH) anomaly, for nowcast and all forecasts. Global and Gulf of Mexico distributions, RMSE and bias statistics computed and tracked. 13 6-10 November 2017 GODAE Annual Science Team meeting (GOVST-VIII) , Bergen, Norway

14. Class-4: SST NCEP RTG Global Gulf of Mexico Daily comparison between Global RTOFS and RTG SST anomaly, nowcast and all forecasts. Global and Gulf of Mexico distributions, RMSE and bias statistics computed and tracked. 14 6-10 November 2017 GODAE Annual Science Team meeting (GOVST-VIII) , Bergen, Norway

15. Class-4: ARGO Profiles PARALLEL PRODUCTION At this location/date, the temperature profiles are similar between the parallel and production models, but the parallel salinity profile shows substantial improvement over the production profile. 15 6-10 November 2017 GODAE Annual Science Team meeting (GOVST-VIII) , Bergen, Norway

16. Class-4: ARGO Profiles Weekly Average Statistics Global 5 Regions (Gulf Stream shown here) Production (blue) and Parallel (red dash) show overall good agreement in global average for T&S RMSE. The Parallel Temp Bias show somewhat less variability during this period. Regional averages showed more disagreement between the two models, especially in active regions, one of the reasons we chose to focus on them. 16 6-10 November 2017 GODAE Annual Science Team meeting (GOVST-VIII) , Bergen, Norway

17. NCEP/EMC Reorg and Future Plans • Marine Branch validation is now part of Validation and Post-processing Product Generation Branch (VPPG). • Ongoing effort to formalize and standardize validation processes across all EMC. • Concurrent with reorg is a complete redesign and expansion of production suite metrics. • A brief note on the Multimodel Ensemble: • Incorporating GIOPS (Canada) and OpenMAP (BOM) to ensemble suite. Currently working on dataflow and leveraging new biggish data capability in Python. 17 6-10 November 2017 GODAE Annual Science Team meeting (GOVST-VIII) , Bergen, Norway

18. Summary • Use of Metrics works well for model diagnostics and evaluating upgrades. • All classes of metrics provide for a diverse evaluation which offsets paucity of observations. • Regional metrics provide useful information on differences which Global metrics may not capture. • Appropriate regional metrics need to be defined for specific regions/coastal interests (transports, fronts etc.). • Regional metrics will require higher frequency and resolution of measurements. • Engagement with regional stakeholders/users/applications. 18 6-10 November 2017 GODAE Annual Science Team meeting (GOVST-VIII) , Bergen, Norway