                  CTD CALIBRATION: CRUISE CIROLANA 4/1991                  
                                                                           
CTD profiles were corrected using calibration coefficients derived from the
wash part of the cruise. A summary of the results is presented herein.     
                                                                           
                                                                           
Temperature                                                                
CTD temperature was corrected by applying the coefficients derived from the
laboratory calibration of the May 1991 data:                               
                                                                           
  T(cor) = T(ctd) + dT                                                     
                                                                           
where dT = c + b*T(ctd) + a*T(ctd)*T(ctd)                                  
and    a = -1.51027x10-5                                                   
       b =  4.195017x10-4                                                  
       c =  2.6047917x10-3                                                 
                                                                           
                                                                           
Pressure                                                                   
CTD  pressure was corrected by applying the coefficients derived  from  the
laboratory calibration of May 1991:                                        
                                                                           
  P(cor) = P(ctd) + dP                                                     
                                                                           
where dP = a*T(cor) + b*P(ctd) + c                                         
and    a =  0                                                              
       b =  0                                                              
       c = -1.5                                                            
                                                                           
                                                                           
Conductivity Ratio                                                         
CTD  conductivity was corrected by converting water sample salinity  to  in
situ  conductivity  (from  the UNESCO algorithm) and comparing  it  to  CTD
conductivity  values.  The  water sample salinity  was  measured  using  an
AutoLab bench salinometer.  A least squares regression was performed on the
corrected data to derive the calibration coefficients a, b and c:          
                                                                           
  CR(ws)/CR(ctd) = a*T(cor) + b*P(cor) + c                                 
                                                                           
The corrected conductivity ratio is then calculated from:                  
                                                                           
  CR(cor) = CR(ctd)*(a*T(cor) + b*P(cor) + c))                             
                                                                           
The calibration coefficients for the Wash stations are:                    
     a = 0.107292496x10-3                                                  
     b = 0.649354289x10-5                                                  
     c = 0.999034200                                                       
                                                                           
The  root mean square (rms) difference between the corrected  CTD  salinity
and  water  sample  salinity  from  the Wash stations  was  0.007  for  130
observations.                                                              
                                                                           
The calibration coefficients for the Humber stations are:                  
     a =  0.18683543x10-2                                                  
     b = -0.191654913x10-4                                                 
     c =  0.985682063                                                      
                                                                           
The  root mean square (rms) difference between the corrected  CTD  salinity
and  water  sample  salinity  from the Humber stations  was  0.030  for  38
observations.                                                              
                                                                           
The calibration coefficients for the Irish Sea stations are:               
     a = -0.197658929x10-3                                                 
     b =  0.372065961x10-5                                                 
     c =  1.00134185                                                       
                                                                           
The  root mean square (rms) difference between the corrected  CTD  salinity
and  water  sample  salinity from the Irish Sea stations was 0.006  for  38
observations.                                                              
                                                                           
Suspended load calculated from:                                            
                                                                           
  S/L (mg/l) = Aloge(%T) + B                                               
                                                                           
where A + B as below:                                                      
                                                                           
    Station       A         B                                              
     8 -  87    -12.0     49.0                                             
    89 - 111     -8.0     40.0                                             
   113 - 184    -16.0     56.0                                             
   212 - 236     -7.0     28.0                                             
   245 - 257    -15.0     54.0                                             
