Observations and results from the hiss recorder an instrument to continuously observe the VLF emissions

An ins trument, developed at NBS, has enabled continuous observations of VLF emiss ions. The continuous data has permitted the identifi cation of some new characterist ics of VLF emissions, and new information on the statistics of the occurrence of VLF e mission activity. The contin uous recordings are able to document the morphology of VLF emiss ion events and, therefore, acc ura tc correlations with other geophysical phenom ena are possible. Co rrelations of VLF em ission activity with abno rm al D-region absorption, X-ray events , and magnetic a ctiv ity are prcsented.