***  Documentation  for the CTD data from the Challenger 73 cruise  in  the                                                         
Clyde  Sea  and  Liverpool Bay carried out by University of  Wales,  Bangor                                                         
during November December 1990 under the direction of Prof. J.H. Simpson                                                             
                                                                                                                                    
                                                                                                                                    
THE  DATA IS ALREADY CALIBRATED.  Coefficients and method are given  below.                                                         
Density  has been derived using the formulation recommended in Unesco Tech.                                                         
reports 36,38,40 (1981).                                                                                                            
                                                                                                                                    
Instrument used                                                                                                                     
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Neil Brown Instruments System Mark III CTD                                                                                          
The observed parameters were pressure, temperature,  conductivity,  disolve                                                         
oxigen, attenuation and Chlorophyl. The typical instrument descent rate was                                                         
1 m/s. Data were logged through the A,B,C Levels of RVS ship board system.                                                          
                                                                                                                                    
Calibration                                                                                                                         
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Temperature  was calibrated using standard reversing thermometers (0.001  C                                                         
accuracy)  and  salinity  samples  from a rosette.  Salinity  samples  were                                                         
measured with Autosal Model 8400A.  Samples were collected from well  mixed                                                         
regions  of  the water column to ensure good calibration.  The  calibration                                                         
data for each cruise now follows: temperature and salinity calibration were                                                         
calculated as a difference.                                                                                                         
                                                                                                                                    
Temperature = CTD temperature + dT (degrees C)                                                                                      
                                                                                                                                    
Salinity = CTD salinity + dS (PSU)                                                                                                  
                                                                                                                                    
Cruise CH73                                                                                                                         
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Mean dT -0.003                                                                                                                      
                                                                                                                                    
Standard deviation dT 0.011                                                                                                         
                                                                                                                                    
Mean dS 0.003                                                                                                                       
                                                                                                                                    
Standard deviation dS 0.009                                                                                                         
