PART VI: WATER CHARACTERISTICS 



49. Monthly averages of daily measurements of surface water tempera- 

 ture, visibility, and density at the seaward end of the FRF pier are given in 

 Table 17. The summaries represent single observations made near 0700 EST and, 

 therefore, may not reflect daily average conditions, since such characteris- 

 tics can change within a 24-hr period. Large temperature variations were com- 

 mon when there were large differences between the air and water temperature 

 and variations in wind direction. From past experience, persistent onshore 

 winds pile up warmer surface water along the shoreline, while offshore winds 

 cause colder bottom water to circulate upward resulting in lower temperatures. 



Table 17 

 Mean Surface Water Characteristics 



















Temperature, ° 

 1980- 



C Visibility, m 

 1980- 



Density, 



g/cm 3 

 1980- 



Month 



1986 



1986 



1986 



1986 



1986 



1986 



Jan 



7.6 



5.7 



1.3 



1.2 



1.0247 



1.0238 



Feb 



5.3 



4.7 



2.1 



1.6 



1.0228 



1.0233 



Mar 



6.4 



6.6 



2.6 



1.4 



1.0230 



1.0230 



Apr 



11.6 



11.0 



2.2 



2.0 



1.0218 



1.0226 



May 



15.2 



15.1 



2.5 



2.4 



1.0222 



1.0226 



Jun 



19.3 



19.4 



3.6 



3.6 



1.0227 



1.0216 



Jul 



22.8 



21.7 



4.9 



3.8 



1.0218 



1.0216 



Aug 



22.4 



23.2 



3.4 



2.9 



1.0215 



1.0205 



Sep 



22.7 



22.5 



1.9 



2.0 



1.0215 



1.0210 



Oct 



19.5 



19.3 



1.3 



1.3 



1.0223 



1.0217 



Nov 



15.6 



14.8 



1.0 



0.9 



1.0226 



1.0227 



Dec 



10.2 



10.2 



1.1 



1.0 



1.0224 



1.0232 



Annual 



14.9 



14.4 



2.4 



2.0 



1.0224 



1.0223 









Temperature 







50. Daily sea surface water temperatures (Figure 30) were measured with 

 an NOS water sampler and thermometer. Monthly mean temperatures (Table 17 and 

 Figure 31) varied with the air temperatures (see Table 2). 



Visibility 



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

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



62 



