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

 absorption and attenuation characteristics of the water which vary daily and 

 yearly. 



52. Visibility was measured with a 0.3-m-diam secci disk and, similar 

 to water temperature, variation was related to onshore and offshore winds. 

 Onshore winds moved warm clear surface water toward shore, while offshore 

 winds brought up colder bottom water with large concentrations of suspended 

 matter. Figure 32 presents the daily surface visibility values for the year. 

 Large variations were common, and visibility less than 1 m was expected in any 

 month. 



53. Monthly means are given in Table 17 and shown in Figure 33. 



Density 



54. Daily surface density values, shown in Figure 34, were measured 

 with a hydrometer. Monthly means are given in Table 17 and plotted in 

 Figure 35. 



64 



