Observations of Infragravity Waves During 

 SAMSON and DELILAH 



The SAMSON and DELILAH experiments were held at the FRF in fall 1990. 

 The objectives of DELILAH were to measure wave and wind forced three- 

 dimensional nearshore dynamics while monitoring the bathymetric response. 

 Particular emphasis was placed on measuring infragravity waves, shear waves, 

 mean circulation, runup, and setup. DELILAH was conceived as an experiment 

 of opportunity for nearshore measurements, taking advantage of the 

 simultaneous directional wave measurements from the FRF 8-m array and from 

 an array at 13-m depth installed for the SAMSON experiment (Figure 15). The 

 SAMSON experiment began 1 Sep 1990 and parts of the experiment (8m and 

 13m array data) continued to be active through April 1991 . The DELILAH 

 experiment was a short, 3 week intensive effort between 1 and 21 Oct 1990. 





Figure 15. Bathymetric plot with locations of the FRF, SAMSON, and 

 DELILAH arrays in October 1990 



The DELILAH surf-zone array was designed to measure infragravity and 

 shear waves using a primary cross-shore array with two imbedded longshore 

 arrays (Figure 16). The cross-shore array consisted of nine instrument packages, 

 each having a Marsh McBirney electromagnetic current meter (EMCM) and two 

 pressure sensors (one ParosScientific and one Setra Sensors). Nine other 



34 



Chapter 4 Field Observations 



