ve field Wave Direction(deg) 
  
  
are two 
and 225 
leg, the T of Japan Ce 
s shows 
> deg is 
tion is 
and 90 Tokumitu ley 
3/8 of Cot d 
ded that am "^" Frequency(Hz) e 
m 06 Fig.7 The wave number spectrum distribution of e 
he simulated wave of Fig.5 in the wave Matto 
ng Wave direction-frequency space = 
ineering 
4. MARINE RADAR OBSERVATION 
RESULT AND DISCUSSION 
The marine radar site was shown in Fig.8 and Fig.8 The marine radar site 
Fig.9. We observed the target area on Jan.5-6, 
1995, when the most highest wave was observed 
by the wave observational system of in situ data 
by Ministry of Construction Japan at the same 
area as Fig.8. The PPI image was converted by 
A/D convertor and saved into the computer for 
analysis. 
Fig.10 shows the result of comparison between p 
wave direction by marine radar and the in sits 
data. From this result the wave direction is same 
as in situ data except the case pre-processed by 
Hanning window only. Another two case filtered 
radar by moving average have good correlation to the 
observed data. 
And Fig.11 shows the result of comparison | un 1 
| between wave frequency and in situ data. This 
50.0 
1500m 
  
1000m 
    
    
  
\ Offshore Breakwater 
  
= 
Tokumitu Coast 
shows the frequency observed by marine radar is Se ani 
larger than the data from in situ data. ppm : 
The error depends on the reason that we use 
M small amplitude wave theory on translating from 
spatial f requency monitored by marine radar to : 
üme series frequency. Translation from spatial Fig.9 Theobservatonal arca 
frequency to time series frequency is a big 
500 problem on wave theory. Making allowance for 
the reason mentioned above, we find that it is 
accurate enough for operational use. 
  
50.0 
bution of 
Kx-Ky 
255 
International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B7. Vienna 1996