north, predicted in the rose plots, is verified. 



101. Since these meters are not in the eastern side of Cerritos Channel 

 but only near its entrance, the relative proportions cannot be assigned as 

 either into or out of the channel. However, times of northwesterly flow like- 

 ly correspond to periods of inflow into the eastern channel entrance, 

 southeasterly to outward flow. These periods are roughly in phase with the 

 western entrance periods. Thus the channel filled and drained from both 

 entrances approximately in phase, requiring the existence of a node somewhere 

 at the back of Cerritos Channel. Examination of the currents at site CM1 

 should indicate the location of the node. 



102. If the nodal point occurs westward of Site CM1 , floods will result 

 in westerly or counterclockwise flow, ebbs in easterly; if eastward of 



Site CM1, the reverse. Plates 31 and 32, 2-day vector time series of surface 

 and bottom currents, respectively, do not present such a simple pattern. On 

 the morning of the 7th, the flood produced a southwesterly flow on the sur- 

 face, but during the strongest ebb on either side of midnight, the current 

 reversed several times. The subsequent flood produced much lower velocities 

 in a variety of directions. Bottom currents are also capable of flowing in 

 either direction during a flood or ebb. 



103. Current profile Stations P9 through P12 were selected with the 

 intent of locating the nodal point. If it were stationary, flows would con- 

 verge at stations on either side of it during flood and diverge during ebb. 

 Figure 13 is a simplified reduction of the profile data at the top, middepth, 

 and bottom, respectively, wherein a vector represents the amplitude of the 

 flow along the channel axis in either the clockwise (right) or counterclock- 

 wise (left) direction, or perpendicular to the channel axis (up or down). 



104. Inspection reveals that the flow in the Cerritos Channel cannot be 

 described as simply converging and diverging to a single, stationary nodal 

 point. Not only does the node migrate along the channel, converging flows do 

 not always produce a node at the same location as diverging flows. Both types 

 are evident at the middepth at near 2000 hr on 8 August. Also, there is con- 

 siderable vertical stratification of the flow and the nodal points. Modes of 

 oscillation perpendicular to the channel axis become apparent as the longitu- 

 dinal flow approaches zero. These and other higher frequency modes of oscil- 

 lation are poorly defined at the sampling rate of one measurement every 20 to 

 30 min used in the current profiles. Examination of the in situ meter's time 



36 



