Annual 



Table 10 

 Mean Surface Water Characteristics 

























Temp 



erature, 



°C 



Vis 



ibility, 



m 



3 



Density, g/cm 







1980- 



1980- 





1980- 



1980- 





1980- 



1980- 



Month 



1985 



1984 



1985 



1985 



1984 



1985 



1985 



1984 



1985 



Jan 



7.0 



5.0 



5.4 



1.4 



1.2 



1.2 



1.0255 



1.0238 



1.0241 



Feb 



4.3 



4.6 



4.5 



2.2 



1.5 



1.6 



1.0248 



1.0237 



1.0239 



Mar 



7.9 



6.3 



6.6 



3.5 



1.4 



1.7 



1.0245 



1.0233 



1.0235 



Apr 



12.6 



10.5 



10.8 



2.8 



2.0 



2.1 



1.0241 



1.0231 



1.0233 



May 



17.0 



14.8 



15.1 



2.6 



2.4 



2.4 



1.0240 



1.0230 



1.0232 



Jun 



19.4 



19.4 



19.4 



4.0 



3.6 



3.6 



1.0235 



1.0215 



1.0219 



Jul 



22.3 



21.5 



21.4 



3.3 



3.7 



3.6 



1.0227 



1.0219 



1.0221 



Aug 



24.4 



23.0 



23.3 



2.7 



3.0 



2.9 



1.0216 



1.0207 



1.0208 



Sep 



22.7 



22.6 



22.5 



2.6 



1.9 



2.0 



1.0213 



1.0213 



1.0213 



Oct 



21.4 



18.8 



19.2 



2.6 



1.1 



1.4 



1.0208 



1.0222 



1.0219 



Nov 



17.7 



14.0 



14.6 



1.2 



0.9 



0.9 



1.0221 



1.0235 



1.0232 



Dec 



11.3 



10.0 



10.2 



1.3 



1.1 



1.1 



1.0232 



1.0240 



1.0238 



15.7 



14.2 



14.4 



2.5 



2.0 



2.1 



1.0232 1.0227 1.0228 



Present versus past years 



73. In general, the temperatures were warmer during 1985 than in prior 

 years. With the exception of February, June, and September, monthly means 

 (see Figure 36) were consistently over 1 deg warmer resulting in an annual 

 difference of 1.5° C. 



All years 



74. The distribution of surface water temperatures for all years com- 

 bined is shown in Figure 37. Temperatures in excess of 25° C can be expected 

 almost 5 percent of the time (or 18 days per year) , while temperatures below 

 4° C can be expected 21 days per year. 



Visibility 



75. Visibility in coastal nearshore waters depends on the amount of 

 salts, soluble organic material, detritus, living organisms, and inorganic 

 particles in the water. These dissolved and suspended materials change the 

 absorption and attenuation characteristics of the water which vary daily and 

 yearly. 



59 



