sensor. That is, if the threshold of sensitivity (the smallest change to which a 

 sensor will respond with a significant measure of reliability in a meaningful 

 time interval) is "A" units of measure in profile amplitude and "B" units of 

 measure in profile interval, then it may be suggested that this threshold interval 

 serve as an initial estimate of the line thickness in the graphical solution plane, 

 and that the grid of the plane be chosen such that A units of amplitude equate 

 to B units of interval . 



PROFILE REGRESSION PROGRAM 



Subroutine "REDUCE" (Appendix) may be used to fit sets of straight lines 

 to digital BT profiles in the National Oceanographic Data Center format. This 

 program has been used in conjunction with a master program for restructuring the 

 NODC BT file for quick archival and retrieval . 



A. Input/Output Data Linkage 



Data linkage with the users main program is achieved with the use of a 

 common memory block that is labeled "PROFILE". The number of data points, 

 N, and the digital profile, T(J), (J= 1 , N) are specified as input data to the 

 subprogram. It is assumed that the digital profile is repre^nted in Celsius 

 temperature values at five meter intervals, starting from depth zero for J = l . 



The number of profi le regression points, M, regression depths, DL(L), 

 (L = l , M), regression temperatures, TL(L), (L = l , M), and root mean square 

 values of differences between data and corresponding regression temperatures 

 in the intervals of fit, RMS(L-l), (L=2, M), are specified as output from this 

 program. Temperatures and RMS values are Celsius degrees. Depths are 

 expressed in the scale of input subscript intervals, and may be converted to 

 meters with the equation 



D(J) = 5.*(DL(J) -1.0). (12) 



The root mean square (RMS) values are computed for intervals, commencing 

 with the interval between DL(1) and DL(2), and ending with the (M-I)th 

 interval, between DL(M-I) and DL(M). The arguments summed are the 

 differences 



(T(J) - T;)2 (13) 



21 



