Accession Number : AD0679166

Title :   THE MEANINGFUL USE OF THE SECCHI DISC.

Descriptive Note : Technical rept.,

Corporate Author : JOHNS HOPKINS UNIV BALTIMORE MD CHESAPEAKE BAY INST

Personal Author(s) : Williams,Jerome

Report Date : NOV 1968

Pagination or Media Count : 18

Abstract : The Secchi Disc is examined in terms of a target seen by the human eye under threshold contrast conditions. Results indicate that the Secchi Disc Reading is related to both the extinction coefficient and the beam transmittance coefficient. There appears to be no way to separate the two from the use of the Secchi Disc alone. In addition, if these readings are to have any meaning at all it is strongly indicated that an optical filter be placed in the system when readings are taken. Special colored glasses are suggested for this purpose. (Author)

Descriptors :   (*WATER, LIGHT TRANSMISSION), (*OPTICAL INSTRUMENTS, *LIGHT TRANSMISSION), VISIBILITY, OPTICAL FILTERS, UNDERWATER LIGHT

Subject Categories : Physical and Dynamic Oceanography
      Optics

Distribution Statement : APPROVED FOR PUBLIC RELEASE