VERIFICATION STRATEGY FOR OCEANS, WAVES & SEA-ICE Robert Grumbine, Avichal Mehra and Arun Chawla NWS/NCEP/EMC

Ocean –Daily/Weekly monitoring of fields using GODAE Class Metrics: Class 1 (analysis of surface fields, e.g. SST, SSH, Sea Ice Cover) Class 2 (vertical sections, e.g. ARGO profiles, WOCE sections) Class 3 (derived products, e.g. Florida Current transports, GS North Wall location) Class 4 (forecast skill metrics, e.g. SST, SSH, profiles) –Daily metrics/stats made available at: Waves –Monitoring of Class 1 and Class 4 metrics –Metrics based on bulk spectral parameters (Significant wave height, Peak Period etc.) –Skill scores typically developed over month long (or more) –Use collocated buoys and altimeters –No consensus on metrics in frequency space yet VERIFICATION

First order variables defining Sea Ice –Sea Ice Concentrations Moderately well observed Poorly predicted In need of metrics –Sea Ice Drift Speeds Well observed (buoys, SSMI) Established metrics –Sea Ice thickness Poorly observed In need of metrics Work in progress but much to do SEA ICE VERIFICATION

Class 1: Sea Ice Cover in the polar regions OCEAN-ICE VERIFICATION

Class 2 & 4: Global RTOFS profiles vs ARGO data OCEAN VERIFICATION

Class 4: Global wave model skill scores for 72 hour forecast Monthly skill scoresSeasonal skill scores Skill scores based on comparisons at all available NDBC buoys, time in MM/YY New Physics introduced WAVES VERIFICATION

Class 1: Wave hindcast Significant wave height bias maps (in m) using collocated altimeter tracks WAVES VERIFICATION

RTOFS Verification and Metrics –Garraffo et al., Modeling of 137Cs as a tracer in a regional model for the Western Pacific, after the Fukushima Daiichi Nuclear power plant accident of March Weather and Forecasting. doi: – Ryan et al., GODAE Ocean View Class 4 forecast verification framework: Global ocean inter-comparison. J Oper Oceanogr. 7(3) – Divakaran et al., GODAE OceanView Inter-comparison for the Australian Region. J Oper Oceanogr. doi: / X –Hernandez et al., 2015.Recent progress in performance evaluations and near real-time assessment of operational ocean products. J. Oper. Oceanogr. (accepted) Waves –Chawla et al A multigrid wave forecasting model: A new paradigm in operational wave forecasting. Wea. & Forecasting, 28, 1057 – 1078 –Chawla et al Validation of a thirty year wave hindcast using the Climate Forecast System Reanalysis winds.Ocean Mod. RECENT PUBLICATIONS

Waves (contd) –Alves et al The Operational Implementation of a Great Lakes Wave Forecasting System at NOAA/NCEP. Wea. & Forecasting, 29.6: –Alves et al The NCEP-FNMOC Combined Wave Ensemble Product: Expanding Benefits of Interagency Probabilistic Forecasts to the Oceanic Environment. Bull. American Meteo. Soc., 94(12), –Van der Westhuysen, et al. 2013: Development and validation of the Nearshore Wave Prediction System. Proc. 93rd AMS Annual Meeting, Austin, TX. Sea Ice –Robert Grumbine: 2013: Keeping Ice'S Simplicity -- A Modeling Start, MMAB Tech Note 314, 32 pp – Robert Grumbine: 2013: Long Range Sea Ice Drift Model Verification, MMAB Tech Note 315, 22 pp.. RECENT PUBLICATIONS (CONTD)

System coupling metrics immature Not that there are no measures, but …. Examples : –Coupled ocean – waves Mixed layer depths Stokes drift estimates (3 rd moments of spectra, Ardhuin et al 2009) –Coupled ice – ocean Heat flux modulations –Coupled wave – ice Scattering & damping COUPLED SYSTEMS VERIFICATION