                   CTD CALIBRATION: CRUISE CORYSTES 4/1988                 
                                                                           
Date: July 1988                                                            
Area: North East Coast                                                     
CTD: Shallow water unit                                                    
                                                                           
                                                                           
Details of Lowerings                                                       
Altimeter  fitted,  Transmissometer fitted,  logging at 1  per  second  (HP
1000).                                                                     
(a)  4 anchor stations (25 hours) = 100                                    
(b)  9 thorium stations = 9                                                
(c) 10 on CTD section = 10                                                 
(Total = 119 profiles)                                                     
130  uncorrected,  91 corrected data files (not all vertical  profiles;  11
from another source).                                                      
                                                                           
Temperature sensor changed during cruise:                                  
S/N 46712 for stations   7 to 113                                          
S/N 49504 for stations 146 to 218                                          
S/N 46712 for stations 239 to 249                                          
                                                                           
All  temperature records were noisy - changing the sensor did  not  improve
the data quality. An attempt was made to smooth the data with some success.
Salinity  calibrations  satisfactory,  except at anchored station 1.  These
data  was not processed further because of this and we have only  3  anchor
stations with corrected data.                                              
                                                                           
                                                                           
Calibration coefficients                                                   
Pressure:                                                                  
For all stations Pressure calibration of June 1988 used:                   
                                                                           
  P(cor) = P(ctd) + dP                                                     
where dP = -1.5 db                                                         
                                                                           
Temperature:                                                               
                                                                           
  T(cor) = T(ctd) + dT                                                     
where dT = a*T(ctd)*T(ctd) + b*T(ctd) + C                                  
                                                                           
For stations 88-113 and 239-249 (Calibration of August 1988)               
 a =  1.99212x10-4                                                         
 b = -4.3376x10-3                                                          
 c =  6.43x10-2                                                            
                                                                           
For stations 146-218 (Calibration of August 1988)                          
 a =  1.42696x10-4                                                         
 b = -7.07368x10-3                                                         
 c = -1.53x10-2                                                            
                                                                           
Salinity:                                                                  
                                                                           
  S(cor) = S(ctd) + dS                                                     
where dS = C                                                               
                                                                           
For stations  88-113 (AS2): C = 0.10                                       
For stations  53- 80:       C = 0.09                                       
For stations 146-174 (AS3): C = 0.22                                       
For stations 178-186:       C = 0.21                                       
For stations 192-218 (AS4): C = 0.23                                       
For stations 239-248:       C = 0.08                                       
