Ocean Working Group progress

1. Ocean Working Group progress Hendrik L. Tolman Chief, Marine Modeling and Analysis Branch NOAA / NWS / NCEP / EMC Hendrik.Tolman@NOAA.gov

2. overview • Ocean working group • History. • Membership. • Review of issues. • Priorities. • Additional discussion points.

3. OWG • The Ocean Working Group came together in 2009 to provide a list of priorities for JSDI. • List provided. • Limited activity since then due to atmosphere focus of JCSDA. • Recent ocean projects have been funded. • Therefore, it was time to re-energize the OWG. • Revisit membership. • Revisit issues from 2009. • Revisit priorities. • Revisit role of OWG.

4. OWG • Membership • Hendrik Tolman (NCEP, co-chair). • James Cummings (NRL, co-chair). • Pat Hogan (NRL, suggested co-chair). • Eric Bayler, LauryMiller, Li Bi (NESDIS). • Dave Behringer (NCEP). • Gustavo Goni, George Halliwell (AOML) • Alexander Kurapov, Ted Strub (Oregon State University). • Michele Rienecker, Guillaume Vernieres (NASA). • Shan Sun (ESRL)

5. Issues • Altimetry: • Critical for eddy-resolving large-scale ocean modeling. Rapid transition to ops for new instruments • Data quality in coastal areas, particularly representation / removal of tidal signatures. • Assimilation in the presence of tides and internal tides. • Real time quality control. (including partitioning of SSH data into barotropic and baroclinic signals) • Synthetic TS profile data from altimeters. • Jason-2 is now well established, focus for new instruments is on Cryosat. Practical issues for Cryosat are: • Data latency while in SAR mode. • WMO satellite ID needs to be assigned before live wave data feed at Navy can be established. • Ice data (see below).

6. Issues • Sea Surface Salinity data: • SMOS and Aquarius data now fully available. • Data re-processing for Aquarius to be started. • Level 2 data requests received from GODAS and RTOFS, NAVO attempting to access data. NAVO is accessing the data and including in NCODA 3DVAR. • Data accuracy close to target for SMOS, needs some work still for Aquarius (newer instrument). • Data latencies (SMOS 2 day, Aquarius 1day) acceptable for NOAA and Navy. • Assimilation of these data in ocean models still to be tested / developed. • NCEP interest partially based on requirements / requests from downstream users in Ocean Modeling Backbone.

7. Issues • Sea Surface Temperature data: • New instruments. (COMS-1 and NPP VIIRS) • Assessment of data quality at high latitudes, particularly ice-free Arctic Ocean in the summer (physical versus traditional retrievals). • Observing, modeling and assimilation of diurnal cycle in SST still of great interest. • NCEP and Navy prefer level 2 data, other international partners use level 3 data (Mercator, Blue Link).

8. Issues • Ocean Color: • Significant interest from NCEP (move towards ecosystems modeling), less so from Navy. Both have some interest in use of data for addressing penetration of heat fluxes in the upper ocean. • SeaWIFS climatology re-built at NCEP, working on impact study (previous presentation). • Looking for older (MERIS) and new (Sentinel) European data to work with.

9. Issues • Sea ice (not addressed in 2009): • Transition from SSMI to SSMI-S still ongoing. • Recent focus on Arctic due to increasing ice-free: • Navy HYCOM Arctic Cap model operational. • Sea ice in global ocean models (HYCOM, CFS). • Ice model critical in global coupled ocean-atmosphere models at both weather and longer time scales. • Ice thickness (Cryosat) is a new capability with potentially large impact on validation of /assimilation in ice models. • SAR data has been used for ice edge detection. Presently used with man-in-the-loop approach. Other SAR use: • Ice concentration products, • Wind field products, • Dominant wave direction and length products, • Wave spectra.

10. Issues • Ocean data assimilation: • Going toward unified assimilation approaches for low-resolution and eddy resolving models. • Consolidate NOAA and Navy assimilation methods to maximize leveraging of efforts, as well as NCEP DA methods for weather and climate scales. • NOAA is progressing with experiments with LETKF approach with GODAS, moving toward hybrid approach. • Hybrid versions of NCODA are also being developed (using ensembles generated via ensemble transform (ET) technique. • Benefits of shared development environment (NOAA, Navy, partners) are generally recognized.

11. Issues • Wind Wave issues: • An NCODA wave height assimilation scheme is used at FNMOC for WAVEWATCH III. • A 4D-var method for SWAN is transitioning into operations from NRL Stennis. • A variational wave height assimilation scheme for WAVEWATCH III is in development at NCEP. • Consolidating the above, focusing on var. approaches. • WAVEWATCH III partitioning with full space-time provides new opportunities to assimilate SAR data. • Navy-NOAA joined interest in processing SAR data. • Waiting for Sentinel-1 for live C-band data feeds. • Altimeter wave data of high value due to NRT availability and low volume of data. Waiting for proper operational data feed for Cryosat altimeter data.

12. Issues • HF Radar data (not addressed in 2009): • These data are of potentially large impact for coastal ocean modeling (mostly circulation, potential for waves only through WERA system). • OWG recognizes that this is outside the traditional scope of JCSDA (ground-based remote sensing, coastal rather than global data), we nevertheless want to recognize the potentially large impact of these data on operational weather time scale coastal ocean models. • These data are highly complementary to satellite data, as the latter tend to have insufficient resolution and/or accuracy near the coast. • The OWG will need input from executive team on this.

13. Priorities • In 2009, the OWG identified clear priorities in the above bulleted list. No clear priorities where identified in 2012. The OWG makes the following observations (not to be confused with priorities). • Altimetry remains crucial for eddy-resolving ocean models. Availability of data (rapid transit into operations) as well as improvement of assimilation methods are key elements for (improving) operational ocean modeling. Special attention should be giving to combining Altimeter (SSHA), SSS and SST data. • SAR data is very versatile, but not used much in modeling yet. Automated processing and data procurement mechanisms are an issue. The latter is expected to improve with upcoming satellites.

14. Priorities • OWG observationscontiued: • Whereas JCSDA naturally has a global focus, many ocean modeling users focus on the coast. This makes coastal issues potentially important from an end-user perspective. • Ice modeling and ice data have become highly visible and important in recent years, making it a natural new high-priority focal point.

15. Additional discussion points • Additional discussion on the OWG has focused particularly on coastal modeling. • Interest in coastal modeling due to the physical intersection of modeling and end-users at the coast, but • This is traditionally on the outside of the scope of JCSDA due to its local nature, and due to the dominance of in-situ and land-based remote sensing data in coastal areas. • The OWG intends to seek input from coastal modelers for two main reasons: • Joint interest in development of ocean data assimilation techniques. • Considering coastal ocean modelers as an important and highly visible end-user providing requirements for global and basin-scale efforts.

16. Additional discussion points • Traditional partners in this context would be NOAA-NOS, NOAA-IOOS and USGS, as well as various non-government partners. • In this context, the OWG requests that the JCSDA executive team discuss if it is practical and/or feasible to introduce for instance NOS as a new partner in JCSDA. • The OWG intends to discuss its future roles and focuses in the coming months.

17. Questions ?