                 CTD CALIBRATION: CRUISE CORYSTES 11C/1989                 
                                                                           
Date: October 1989                                                         
Area: North East Coast                                                     
CTD: Shallow water unit, S/N 47341                                         
                                                                           
                                                                           
Details of Profiles                                                        
Altimeter  fitted,  Transmissometer  fitted,  Niskin  bottles  on   Rosette
sampler, logging at 1 sample per second (HP 1000A).                        
18 vertical profiles                                                       
                                                                           
                                                                           
Calibration details                                                        
Comparison  between  CTD pressure and height above seabed.  Good  agreement
resulted confirming the post cruise calibration at approximately 11 deg C. 
                                                                           
DSRTs  compared with CTD temperature sensor.  Not very good  agreement  but
differences  between  left  and  right  hand  thermometers  suggested  that
thermometer  temperatures  might  be  unreliable.  Good  calibrations  were
obtained during cruises 11A and 11B, confirming the pre-cruise calibration.
                                                                           
Water samples were collected for salinity analysis and for comparison  with
CTD.                                                                       
                                                                           
                                                                           
Corrections applied                                                        
Pressure calibration of 16 November 1989 (post-cruise):                    
                                                                           
  P(cor) = P(ctd) + dP                                                     
where dP = a*P(ctd)*P(ctd) + b*P(ctd) + c                                  
and a = 9.53486e-5                                                         
    b = 1.82488e-3                                                         
    c = -0.48                                                              
                                                                           
Temperature calibration of October 1989 (pre-cruise):                      
                                                                           
  T(cor) = T(ctd) + dT                                                     
where dT = a*T(ctd)*T(ctd) + b*T(ctd) + c                                  
and a = -5.13940e-5                                                        
    b = -4.68187e-3                                                        
    c = 2.0608e-1                                                          
                                                                           
Salinity:                                                                  
                                                                           
  S(cor) = S(ctd) +dS                                                      
where dS = -0.182                                                          
