where T = 30.8 sec is a characteristic period provided by Datawell. The 

 manufacturer states that this sensitivity decrease results in amplitude errors 

 of less than 3 percent for oscillation (wave) periods less than 15 sec. Fig- 

 ures A1 and A2 present curves for (DW) = /A/ - 1 , the Datawell-predicted 

 sensitivity decrease error, and, as can be seen, the actual sensitivity does 

 not decrease with period according to the Datawell relationship given in 

 Equation A1 . 



Difference Error (d) 



4. This is the difference (d) between the Datawell-predicted decrease 

 in sensitivity error and that found from the actual buoy calibrations. 



5. In Tables A2 through A5, DW (Datawell-predicted error) and d 

 (difference error) are tabulated as a function of T (and frequency) for each 

 buoy. Best accuracy would be obtained by choosing the calibration values 

 nearest in time to the date of the measurements. 



6. Since these error corrections are oscillation-period dependent, 

 their application requires that the wave data be decomposed into amplitude 



DATAWELL SPECIFICATION 



• 7 APRIL 1982 NOAA/ESO 



■ 8 NOVEMBER 1983 A.R.ASSOC 



PERIOD. SECONDS 



Figure A1. Waverider 66966 predeployment and 

 postdeployment calibrations 



A2 



