FRF Permanent Instrumentation 
A group of instruments that is permanently installed at the FRF allows for 
the continuous collection of oceanographic and meteorologic data. During 
large cooperative experiments, such as DELILAH, these instruments not only 
provide researchers with information on conditions during the experiment, but 
also with an invaluable archive of data from which to compare and interpret 
trends. The permanent instrumentation includes the 8-m array; Baylor wave 
gauges; waverider buoy; and gauges for wind speed, wind direction, tide, 
atmospheric pressure, and temperature. Table E3 lists the FRF permanent 
instruments by name and number and includes gain, bias, coordinates relative 
to the FRF coordinate system, and gauge depth. Figure E3 is a schematic 
depicting the location of these instruments. 
An additional numbering convention for FRF permanent instrumentation is 
used to refer to combinations of gauges. This is a four digit gauge number that 
associates a name with the results of a multi-sensor data analysis. Among 
these four-digit combination gauges are 3111, which is the pressure sensors in 
the 8-m array; 3519, which is the vector averaged currents of the PUV gauge 
in the 8-m array; and 3932, which is the vector averaged wind speed and 
direction. Statistics from these and other gauges show the basic climatology 
during DELILAH in Figure E13. 
8-m Array 
The 8-m array is composed of a linear longshore array of ten pressure 
sensors (Nos. 101-191), a cross-shore array of five pressure sensors (Nos. 211- 
251), and a combination pressure/current meter (PUV) (Nos. 511, 519, and 
529) within the array. The fifteen pressure gauges are mounted approximately 
0.5 m off the bottom in the vicinity of the 8-m isobath. The array employs 
pressure sensors, manufactured by Senso-Metrics Inc., with a range of 0-25 
psir (pounds per square inch relative to 1 atm). Each sensor was statically 
calibrated prior to deployment and mounted on a 2-in.-diam pipe jetted into the 
ocean bottom. A complete analysis of the data results in a three-dimensional 
directional spectra as illustrated in Figures E14 through E24. Characteristic 
wave heights from spectral observation are most frequently given as H,,,, 
which is four times the standard deviation of sea-surface displacement. It can 
be determined from the volume under the frequency-direction spectrum by the 
equation: 
5 N M 
Hr, = 16) Y S(,,8,,) afa0 (1) 
It can also be found from the integrated frequency spectrum by: 
Appendix E Stationary Instrument Data E21 
