Summary of ELF propagation validation system effective noise measurements, 1976 to 1978

From August 1976 through December 1978, extremely low frequency (ELF) field-strength and effective-noise measurements were taken continuously in Connecticut and sporadically aboard operational submarines. This paper summarizes the effective-noise measurements taken at both Connecticut and sea (North Atlantic, Norwegian Sea, South Atlantic equatorial area, Virgin Islands area, Hawaii area, Western Pacific, and Northwestern Pacific) locations during this period. The main conclusion is that there are often considerable differences in effective-noise levels measured at Connecticut and sea locations. The highest effective noise levels were measured in Connecticut during the summer months, while the lowest effective-noise levels were measured in the South Atlantic equatorial area during November.