100 



80 



S, 60 - 



40 



20 



E Buoy 51 026 



■ WIS STA 5 



■ WIS STA 3 

 E3 WIS STA 31 



112-5 135 157.5 180 202.5 225 247.5 270 282.5 



Wave Direction Center (deg) 



Figure 33. Deepwater wave climate comparison, 6 m (deg, coming from) 



preferences for waves from the east, east-northeast, and northwest Stations 3 

 and 5 also show a concentration of waves from northerly directions but the main 

 concentration is centered on north. Despite these differences, it is concluded that 

 the deepwater wave climate offshore from Maui's north coast is adequately 

 represented by the available buoy measurements and long-term WIS station. 



Wave Climate at Kahului Harbor 



The deepwater wave climate analysis suggests that data from the array, which 

 covers a time period comparable to the NDBC buoy and special hindcast sources, 

 would reasonably characterize the wave climate immediately incident to Kahului 

 Harbor. The array measurements incorporate local effects of sheltering and 

 bathymetry. 



To further validate the use of array data as the incident wave climate, an 

 approximate procedure was used to relate the 20-year WIS hindcast to Kahului 

 Harbor entrance. The procedure was to develop an empirical transformation 

 between NDBC buoy and array measurement sites and then apply the trans- 

 formation to the 20-year deepwater climate. 



Wave heights and peak periods in the NDBC buoy and array data sets were 

 segregated by direction bands, based on direction measured at the buoy. Linear 

 regression equations were calculated for bands with more than 100 cases 

 (Table 7). The regression equations were applied to the 20 years of WIS 

 Station 31 information to estimate long-term climate at the Kahului gage. The 

 transformed Station 31 (WIS 3 IT) and array gage summaries are very similar, 

 especially considering the approximations involved in the transformation 

 (Figures 34-36). 



Chapter 3 Wind Wave and Swell Climate 



37 



