Global Real Time Ocean Forecast System (RTOFS-Global)

1. Global Real Time Ocean Forecast System (RTOFS-Global) Team: Avichal Mehra, Ilya Rivin, Bhavani Balasubramaniam, Todd Spindler, Zulema Garaffo, Hendrik Tolman and Deanna Spindler.

2. RTOFS-Global • RTOFS Global will be the first global eddy-resolving ocean forecast system at NOAA/NCEP. • This global system will be based on a 1/12 degree HYCOM (HYbrid Coordinate Ocean Model) with a Pan-Am Global Grid (4500 x 3928). • The system has 32 vertical hybrid layers (isopycnal in the deep, isolevel in the mixed layer and sigma in shallow waters). • The initialization is based on a MVOI scheme (NCODA) developed by the US Navy which assimilates daily observations (T,S, U,V and sea surface height) in a sequential incremental update cycle to produce analysis. • The daily global ocean forecasts at NCEP will be forced with the GFS surface fluxes of radiation, precipitation and momentum.

3. 1/12 Degree Global Domain

4. Motivation • NCEP needs a global eddy-resolving ocean model: • Part of NOAA ocean modeling backbone capability (SAB 2004, NOAA response 2005). • Partnering with NOS and IOOS-RA’s • Part of larger National Backbone capability in strong partnership with Navy. • Internal needs for NCEP: • EMC/OPC / TPC / WFO’s need for real time eddy-resolving ocean products for customers. • MMAB and NOS need for real-time eddy-resolving boundary data for areas of interest: • Coupled regional hurricane modeling. • Atlantic, East Pacific, …. • Centerpiece of integrated ocean modeling system ( e.g. plume modeling for radionuclide dispersion near Japan).

5. Preliminary Monitoring and Diagnostics

6. Gulf Stream location

7. Difference (in degrees) between the feature-based GS location from NAVOCEANO and numerical models. RTOFS-Global is comparable to NCOM (US Navy) 1/32 degree high resolution model of Gulf Stream. Data Provided by OPC RTOFS-Atlantic (Nowcast) RTOFS-Global (Nowcast) NCOM- HiRes (Nowcast) Days since 12/20/1010

8. Daily Bias and RMS differences between OISST and Global RTOFS. Averages over this period were 0.1 °C (Bias) and 1.0 °C (RMS). Data Provided by OPC Daily RMS Daily Bias ° C Dates

11. 2011 Fall AGU Session • OS12: Multi-scale Ocean Modeling and Opportunities for Coastal Marine and Ecosystem Forecast Services Description: NOAA provides a model forecast and computational backbone for multi-scale ocean predictions from global to coastal coverage. Over the past five years, forecast systems have been developed and made operational to support and provide opportunity for local applications. The goal of this session is to publicize these emerging capabilities and stimulate discussion between users of these applications and those who are providing the services backbone. Abstracts on key areas are encouraged, such as 1) operational global/regional/coastal ocean and ecosystem forecast systems; and 2) coupled atmosphere/ocean/ecosystem forecast systems. Emphasis is on lessons learned from established operational systems.

12. Potential Temperature at WOCE section I-8 (top) compared to the same section from RTOFS-Global (bottom)

13. Salinity at WOCE section A-3 (top) compared to the same section from RTOFS-Global (bottom)