The WIS effort uses proven discrete spectral wave models, the best available input wind fields, to produce resulting wave estimates (height, wave period, and direction) and directional spectral estimates for pre-selection output locations along the coast. Extra-tropical (synoptic-scale meteorological systems) and tropical systems must be accurately defined in the wind field specification. Also, smaller scale events such as frontal passage with rapid wind shifts common to development of cyclogenesis can generate rapidly increasing wave conditions. These conditions must be adequately estimated temporally and spatially where the scales can extend into 1000’s of kilometers, and over 30-yr duration of the hindcast effort. The large-scale basins (Atlantic, Pacific, Gulf of Mexico and Western Alaska) use one technique and wind field specification (Swail et al., 2006, Cox and Swail (2001). The Great Lakes domain uses the Coastal Forecast System Reanalysis (CFSR, Saha, et al. 2010). Details of these wind field methodologies are found at the WIS website. In arctic regions (the Great Lakes, and Alaska) the spatial and temporal evolution (and decay) of shore-fast ice and for the Alaskan waters the migration of northern ice packs must be accurately estimated and implemented. Lastly, the actual wave climate can consist of multiple wave systems, with local wind-seas developing from local meteorological events, interlaced with wave energy derived from distant events comprised by long-period swells.
It is imperative for the WIS effort to evaluate the modeled estimates to actual wave measurements (point-source and satellite based remote sensing systems, e.g., altimeters, synthetic aperture radars). The evaluation process has to extend over the large spatial range, wave climate regimes, and meteorological events. WIS is expanding the evaluation procedures, using new variants of statistical tests, analyses for long-term consistencies and potential errors used in the Quality Control and Quality Assurances of WIS.