Earth and gives many examples of the effects of this phenomenon on coastal 

 areas. Perigee-syzygy alignment, Wood states, can cause tidal flooding within 

 a period of 1 to 3 days following (or in some few cases, a day or so preced- 

 ing) the mean phase or epoch of the perigee-syzygy alignment. Approximately 

 every 1 to 1-1/2 years, the Moon's orbit carries it exceptionally close to the 

 Earth (Wood named this "proxigee"), creating especially amplified tides. The 

 above tabulation identifies three occurrences during October through December 

 1981 of these strong astronomical forces, each coincident with large waves at 

 the FRF. 



94. In November, the perigean spring tide and a subtropical storm 

 (northeaster) produced severe beach erosion, resulting in the destruction of a 

 number of houses in the vicinity of the FRF. The water level rose to 149 cm, 

 the highest water level recorded to date at the FRF. 



Water Characteristics 



Water temperature 



95. Daily sea surface water temperatures at the seaward end of the FRF 

 pier are presented in Figure 29. In 1981, as in 1980, large day-to-day 

 temperature differences occurred in June, July, and August when frequent off- 

 shore winds blew warm surface water offshore, allowing upward and landward 

 circulation of the much colder bottom water. Onshore winds reverse this cir- 

 culation, piling up warm surface water against the shoreline, with a resulting 

 seaward flow along the bottom. 



96. The monthly mean sea surface temperatures for 1981 and 1980 pre- 

 sented in Figure 30 and seasonal distributions of temperatures for 1981 and 

 1980 data, combined in Figure 31, show the seasonal variability typical of 

 this location. However, the winter minimum monthly mean was about 4 deg 

 colder in 1981 than in 1980, and the July mean was about 4 deg warmer than in 

 1980. Overall, the 1981 annual mean was slightly warmer than the 1980 mean 

 (Table 9). 



Sea surface water visibility 



97. 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 thus vary daily 

 and throughout the year. 



57 



