OCL/NODC CODES USED IN THE WORLD OCEAN DATABASE 1998.
 
 OCL CODES ARE THE SAME AS THOSE USED BY NODC EXCEPT WHERE AN 
 NODC CODE IS A CHARACTER VALUE IN WHICH CASE OCL ASSIGNS A 
 NUMERIC EQUIVALENT. THE NODC CODE IS IN PARENTHESIS IF DIFFERENT
 FROM THE OCL CODE.

 FIRST NUMBER: OCL CODE
 SECOND NUMBER: NODC CODE
 THIRD NUMBER: CODE DESCRIPTION

                                
     41   4300    VISIBILITY
     __   ____    __________
      0        -- LESS THAN 50 METERS
      1        -- 50 - 200 METERS
      2        -- 200 - 500 METERS
      3        -- 500 - 1000 METERS
      4        -- 1 - 2 KM
      5        -- 2 - 4 KM
      6        -- 4 - 10 KM
      7        -- 10 - 20 KM
      8        -- 20 - 50 KM
      9        -- 50 KM OR MORE