distribution of visibility for all years combined. Approximately 5 percent of 

 the time the visibility can be expected to exceed 5 m, while over 30 percent 

 of the time it is less than 1 m. 



Density 



Present year 



80. Daily surface density values presented in Figure 41 were measured 

 with a hydrometer. Density, similar to temperature and visibility, shows con- 

 siderable scatter. 



1.029-1 



1.027-1 



1.025-j 



1.023-j 



1.021-i 



1.019-j 



1.017-1 



1.015-j 



1.013- 



* 

 * 



£ 

 o 



\ 



D> 

 >^ 



if) 



Z 

 Ul 

 Q 



1.011 



\*"i vc"-:7 



■ * ■• 



— i 1 1 1 1 1 1 1 1 — : — i 1 ■ 



JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC 

 1985 



MONTH 



Figure 41. Daily sea surface water density, 1985 



Present versus past years 



81. In comparison to prior years, monthly mean density was higher 



before September and lower from October through December (Figure 42) . 



All years 



3 



82. The annual mean density was 1.0228 g/cm with an associated stan- 



3 

 dard deviation of 0.002 g/cm (see Table 10). The distribution of density for 



all years combined is presented in Figure 43. 



63 



