APPENDIX D 



PROFILE FITTING PROCEDURE 



This appendix discusses a procedure developed to mathematically fit 

 a curve to a two-sector Inner Continental Shelf profile. In using the 

 procedure., the values of^four parameters obtained from a profile are 

 required. These p^ram'eters are based on empirically adjusted relation- 

 ships among geometric characteristics of the profiles presented in 

 Appendix C. The curve-fitting procedure is complex compared to other 

 methods, primarily because of its ability to accommodate a wide variety 

 of profile forms, and because the shoreface and ramp are considered 

 separately. The ramp characteristics are determined, and the location 

 of the shoref ace-ramp boundary is specified. An empirical curve is fit 

 to the shoreface sector and a term is used to combine the shoreface 

 and ramp profiles. The result is a function of the form. 



z (x, a, b, c, d) (D-1) 



in which z is the bottom depth below MLW datum, x is the distance 

 from MLW shoreline, and a, b, c, d are shape parameters common to all 

 49 Inner Continental Shelf profiles (App. C) . 



1. Ramp Term . 



The ramp depth, Zy,, may be approximated by the equation of a 

 straight line 



a X + b (D-2) 



in which a is the ramp slope; b is the z^, intercept at x = 0, of 

 the ramp extended to the coast (Fig. 5). The landward limit of the 

 actual ramp, i.e., where the ramp meets the seaward boundary of the 

 concave shoreface on the actual profile, did not appear to exceed 

 7.6 kilometers (4.7 miles) on any of the 49 profiles (App. C) . Accord- 

 ingly, the interval between 7.6 and 30.5 kilometers (4.7 and 19 miles) 

 from shore was used for determining the ramp parameters, a and b. 

 It was not used in calculating the shoreface-ramp boundary coordinates 

 (g, 3c). The arbitrarily chosen outer ramp boundary was 30.5 kilometers, 

 or as far seaward as the first of two or more slope segments between 

 adjacent stations which exceed 0.003. Such an atypical situation exists, 

 for example, when the Continental Shelf is less than 30.5 kilometers 

 wide off eastern Florida. The calculated a and b values as well as 

 the correlation coefficient for each ramp profile as obtained using a 

 least squares method for determining the line that best fit the ramp data 

 were listed in Table 1. In most cases 12 or more points were used to de- 

 fine the correlation coefficient for the ramp segment (Table 1, App. C) . 



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