Record Display for the EPA National Library Catalog
RECORD NUMBER: 5 OF 5| Main Title | The meaningful use of the Secchi disc / | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Author | Williams, Jerome. | |||||||||||
| Publisher | Chesapeake Bay Institute, Johns Hopkins University, | |||||||||||
| Year Published | 1968 | |||||||||||
| OCLC Number | 13440211 | |||||||||||
| Subjects | Seawater--Optical properties ; Oceanographic instruments | |||||||||||
| Holdings |
|
|||||||||||
| Collation | 13 pages : illustrations ; 28 cm. | |||||||||||
| Notes | Includes bibliographical references (page 13). |
|||||||||||
| Contents Notes | 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. |