Table 7-5 

 Marginal Data Sets 



RUN ID 



Problem Encountered 



A0509A 



Capacitance wave gauge not operating properly 



A0613A 



Problem with OBS data collection software 



A0814A 



Sensor EEE in mobile OBS array exposed periodically 



A0912A 



Mobile OBS array not positioned correctly until 12:58:00 



S0409B 



Problem with the coordinated time in the OBS data file 



S0508A 



Initial distance from the bed of the mobile OBS array may be incorrect 

 (corrected after 09:02:00) 



S1309A 



Mobile OBS array - beam axis parallel to flow 



S1310A 



Mobile OBS array - beam axis parallel to flow 



S1311A 



Mobile OBS array - beam axis parallel to flow 



Summary 



Review of experiments and results 



During the SUPERTANK Laboratory Data Collection Project a mobile 

 carriage was used to deploy a variety of instruments across the outer surf 

 zone, with emphasis on documenting sediment suspension in the initial stages 

 of wave breaking. For the majority of experiments conducted, data from a 

 vertical array of five OBS, a vertical array of four EMCMs, and a capacitance 

 wave gauge were collected, and test conditions were recorded on videotape. 

 In addition, a two-day series of tests, dedicated to the collection of data in the 

 sand cloud created by plunging breakers, was conducted using a matrix of 33 

 tightly spaced OBS. 



Initial analysis of the carriage data shows that there is a strong cross-shore 

 gradient in suspended sand load in passing along the channel from the region 

 of incipient breaking into the surf zone. This gradient is accompanied by 

 remarkable change in the behavior of the time series of sediment concentration 

 from an oscillatory signal outside the breakpoint to one comprised of irregular 

 events superimposed on a mean load in the zone landward of initial breaking. 

 The structure of the vertical profile of mean concentration also shifts from its 

 classical exponential shape seaward of breaking to a more linear distribution in 

 the surf zone, and in some cases even inverts. 



134 



Chapter 7 Sediment Suspension Measurements from a Platform 



