Shallow water directional wave gages using short baseline pressure arrays

Directional wave gages that use arrays of closely spaced subsurface pressure sensors are described. A typical array uses three pressure sensors arranged in a 1.8 m equilateral triangle. These arrays are attractive because of their low operation costs and long-term reliability. The short baseline is the same size required for a bottom mounted tripod such as used for the more familiar PUV shallow water directional wave gages. Like the PUV the short array can be considered a single point measurement. This avoids questions of spatial homogeneity associated with large arrays and remote sensing gages in shallow water. An important advantage of the pressure sensors is superior resistance to bio-fouling. Multi-year deployments without maintenance are possible for modem pressure sensors even in highly bioactive waters. The principles of operation, data analysis techniques, and design details are summarized from a users perspective. An example of data from an SBLA deployment in Yaquina, OR shows a storm which measured H-mo of 8 m in 17-m water depth. (C) 1998 Elsevier Science B,V. All rights reserved.