D. Keith Wilson
George V. Frisk
Dept. of Appl. Ocean Phys. and Eng., Woods Hole Oceanogr. Inst., Woods Hole, MA 02543
ECONOMEX was a study of ULF/VLF noise along an eastern US continental shelf/slope region, conducted between January and April 1991. Concurrent measurements of surface wave directional spectra and meteorological parameters were collected as a part of the SWADE experiment. Extended time series of pressure and bottom displacement have now been analyzed, plotted, and compared with predictions based on the local wave spectra. In most cases, the contribution from local sources appears far more significant than distant sources, such as storms. D. H. Cato's dipole source mechanism [J. Acoust. Soc. Am. 57, 1076--1095 (1975)] agrees well with data from sensors ranging in depth between 450 and 2500 m, but the monopole mechanism is also significant at the shallowest sensor (100 m). A new method for evaluating Cato's theory is also discussed. The method, since it involves direct evaluation of the dipole source convolution integral, does not require separability of the magnitude and directional dependence of the surface wave spectrum.