***  Documentation for CTD data collected on RRS Discovery Cruise  72 (May                                                          
- Jun 1975) by the Institute of Oceanographic Sciences (Deacon Laboratory)                                                          
Godalming,  Surrey,  UK.,  under the  direction  of  P. M. Saunders.   ***                                                          
                                                                                                                                    
The instrument used was a Neil Brown Instrument Systems CTD which measured                                                          
pressure,  temperature  and conductivity.  The CTD was  used  alongside  a                                                          
General  Oceanics Rosette Multisampler with 12 water bottles and  a  10kHz                                                          
pinger.  Lowering and retrieval rates of 0.5 to  1.5m/s were employed  and                                                          
the sensors were flushed with distilled water on recovery.  Bottle samples                                                          
and reversing thermometer measurements  were made  on descent and the  sea                                                          
water  samples  were  analysed using a   Guildline  Autolab   Salinometer.                                                          
Reversing thermometers were  calibrated  before  and after the cruise.                                                              
                                                                                                                                    
PRESSURE: In-situ  calibration was possible by comparison between the  CTD                                                          
and   the  pressure  determined  from  pairs  of  reversing   thermometers                                                          
(protected and unprotected).                                                                                                        
                                                                                                                                    
TEMPERATURE: In-situ  calibration  was possible by comparing  of  the  CTD                                                          
temperatures  and reversing thermometers separating the deep  and  shallow                                                          
measurements.                                                                                                                       
                                                                                                                                    
SALINITY: From  the  salinity  of  the  sample  and  from  the   corrected                                                          
temperature  and  pressure  of  the  CTD  the  in-situ  conductivity   was                                                          
determined.                                                                                                                         
                                                                                                                                    
Original  values  were  averaged  over  an  interval  of  one  second  and                                                          
calibration coefficients and correction factors applied.   A time constant                                                          
correction  algorithm was employed to compensate for  the slower  response                                                          
of  the platinum resistance thermometer.  Differences  between  successive                                                          
values  of  each  parameter were examined;  the mean  difference  and  its                                                          
standard  deviation  calculated and values greater than  several  standard                                                          
deviations from the mean difference were checked.  Genuinely suspect  data                                                          
were  then  replaced  by  interpolated  values.  Derived  quantities  were                                                          
computed from algorithms published by Fofonoff et al (1974).                                                                        
                                                                                                                                    
References.                                                                                                                         
                                                                                                                                    
Fofonoff,  N.P.,  Hayes,  S.P. and Millard Jr.,  R.C.  1974 WHOI/Brown CTD                                                          
microprofiler:  methods  of  calibration and  data  handling.  Woods  Hole                                                          
Oceanographic Institution  WHOI-74-89.                                                                                              
