HR: 0800h
AN: OS21B-1526    [Abstracts]
TI: Wave System Analysis of WAVEWATCH III Model Performance
AU: * Hanson, J L
EM: Jeffrey.L.Hanson@erdc.usace.army.mil
AF: US Army Corps of Engineers , Field Research Facility 1261 Duck Road, Kitty Hawk, NC 27949 United States
AU: Tolman, H L
EM: Hendrik.Tolman@NOAA.gov
AF: SAIC-GSO, Environmental Modeling Center NOAA-NCEP 5200 Auth Road Room 209, Camp Springs, MD 20746 United States
AU: Tracy, B A
EM: Barbara.A.Tracy@erdc.usace.army.mil
AF: US Army Corps of Engineers, Engineer Research and Development Center 3909 Halls Ferry Rd, Vicksburg, MS 39180-6199 United States
AB: A goal of operational wave modeling is to correctly capture the physics of wave growth, propagation, and dissipation within the limiting framework of computational efficiency. Although mean or integral properties of the wave spectra are typically used to evaluate model performance, one must look into the spectral details to identify the specific sources of model deficiencies. Here we report on the application of a novel wave system analysis approach to assess source term and propagation behavior in numerical wave models. Specific results from the NOAA WAVEWATCH III model are provided. Efficient image processing tools and unique clustering algorithms are used to isolate and track the temporal evolution of wind sea and swell wave system information contained in monthly series of wave spectra. Using buoy observations as ground truth, both temporal correlation and quantile-quantile statistical analyses of the representation of each observed wave system in the wave model output is performed. This approach allows extremely robust evaluation of wave model performance in the wave height, frequency and direction domains. The results provide distinctive diagnostics of model inputs and source term behavior. Using a test set of QuickSCAT-adjusted NCEP/NCAR reanalysis winds for year 2000 in the Pacific Ocean, a WAVEWATCH III hindcast was evaluated at seven deep-water observation sites around the Pacific basin. Preliminary results from each station are combined into overall estimates of wave system performance in three wave classes: wind sea, young swell, and mature swell. Wave period hindcasts are extremely well represented across all wave systems. Wave direction hindcasts are accurate to the spectral resolution (15-deg) with statistics that improve as waves mature. Wave height hindcasts perform equally well for wind seas and young swell, with a significant decrease in performance for mature swell. The source of the mature swell deficiency is a significant increase in mean square error and a positive wave height bias during winter months. These results are being used to evaluate input winds and identify issues with the source term formulations. The WW3 Pacific hindcast results are being evaluated for use in a new 1995-2004 Pacific Basin hindcast that will be available on the USACE Wave Information Studies web page.
DE: 4560 Surface waves and tides (1222)
DE: 4572 Upper ocean and mixed layer processes
SC: Ocean Sciences [OS]
MN: Fall Meeting 2005