ctd

  PI:              John Morrison
  PI on Optics:    Wilford Gardner, Mary Jo Richardson
  dataset:         CTD profile data averaged at two decibar intervals,
                             including beam attenuation
  project/cruise:  Arabian Sea/TTN-049 - Process Cruise 4
  ship:            Thomas Thompson

 PI Notes and Methodology
 Optics Protocols - Gardner/Richardson
 
 
 Parameter  Description                                  Units

 event      a unique number assigned to each sampling 
              operation, consisting of month MM, day DD,
              hour HH and minute mm
 sta        station number
 sta_std    Arabian Sea standard station identifier
 cast       CTD cast number
 date       date (YYYYMMDD) decoded as follows
              YYYY = year, MM = month, DD = day
              Date converted to UTC(GMT).
 time       time of day in UTC(GMT)                      decimal hours
 lat        latitude of cast, negative = south           decimal degrees
 lon        longitude of cast, negative = west           decimal degrees 
 depth      sample depth reported as meters              meters
 press      sample depth reported as pressure            decibars
 temp       temperature, IPTS-68                         degrees C 
 cond       conductivity                                 milliSiemens/centimeter
 sal        salinity, PSS-78                             dimensionless
 potemp     potential temperature, IPTS-68               degrees C
 sigma_t    sigma-t                                      kilogram/meter^3
 sigma_0    sigma theta (potental density)               kilogram/meter^3
 beam_cp    beam attenuation due to particles            1/meter
 light_bs   backscattered light from a Light             volts
              Scattering Sensor
 fluor      relative fluorescence, corrected by          milligram/meter^3
              Seabird software to chlorophyll-a
 
 nd indicates missing or bad data