                    CTD CALIBRATION: CRUISE CORYSTES 8/1989                
                                                                           
Date: July 1989                                                            
Area: North Sea North East Coast                                           
CTD: Shallow water unit, S/N 47341                                         
                                                                           
                                                                           
Details of Profiles                                                        
Altimeter fitted. Transmissometer fitted. Logging at 1 sample per second -1
(HP 1000).                                                                 
(a)  1 x 25h anchor stations (no data from 1st dip, station 3)             
(b)  3 x 13h anchor stations (no data from 1st dip, station 99, A53)       
(c) 40 station CTD grid      (no data from station 178)                    
(d) 16 miscellaneous CTD stations                                          
118 uncorrected data files.                                                
117 corrected data files.                                                  
                                                                           
                                                                           
Calibration details                                                        
Pressure  calibration before and after cruise.  Doubts over altimeter  data
prevented  usual  comparison between CTD pressure values and  height  above
seabed/water depth,  laboratory calibration prior to cruise used to correct
CTD pressure values (July 1989).                                           
                                                                           
Temperature calibration of July 1989 used, confirmed by DSRT.              
                                                                           
Water samples collected for salinity calibration.  Each anchor station  had
its own salinity correction.                                               
                                                                           
Note                                                                       
Calculation of %Transmission from logged data T1 follows temperature       
Then %Trans = 100 - 2*T1 for T1 >50.0                                      
See program listing in this folder                                         
                                                                           
                                                                           
Corrections applied                                                        
Pressure: from calibration of July 19 no correction necessary              
                                                                           
Temperature:                                                               
                                                                           
     dT = a*T(ctd)*T(ctd) + B*T(ctd) + c                                   
                                                                           
where a = -8.98692e-4                                                      
      b =  2.8007e-3                                                       
      c =  2.036e-1                                                        
                                                                           
Salinity - each anchor station unique                                      
                                                                           
     dS = a*S(ctd) + b                                                     
                                                                           
for AS1: a = -1.83753e-1    b =  6.124     (  4- 30)                       
    AS2: a =  0.0           b = -0.191     ( 69- 83)                       
    AS3: a = -3.7343e-1     b = 12.679     ( 87-104)                       
    AS4: a = -2.37015e-1    b =  7.974     (120-137)                       
                                                                           
Grid stations 139-177: a = -1.91788e-1     b = 6.432                       
     stations  48- 66: as for AS1                                          
     stations 106-110: as for AS3                                          
