The dynamic depth anomaly field frequently displays so much structure that 

 to replicate it with a single function would require a polynomial of prohibi- 

 tively high order. This difficulty was overcome by the use of two-dimensional 

 spline fits of the data. The advantage of spline fitting is that the data 

 which was previously fitted by one polynomial is now fitted by several poly- 

 nomials, allowing much more structure to be represented. Equation (1) can 

 still be used to evaluate the components of geostrophic velocity. 



To put this method into use a spline fit program called SPLAK which 

 employs third-order polynomials was obtained from the National Center for 

 Atmospheric Research (NCAR) Software Support Library. Even with spl ine fits, 

 the area to be analyzed was too large to be fitted by a single spline fit. Thus 

 it was specified that the program have nine rectangles to analyze with the size 

 of the rectangles being left as a variable that could be changed as dictated by 

 the needs of a particular study area. The reasoning for using nine rectangles 

 was that the best fit to the data would occur in the center rectangle where the 

 outer boundary effects were least significant. The total area of interest 

 would then be analyzed by choosing an appropriate size for the nine rectangles 

 according to the amount of structure present and then moving the center rec- 

 tangle around the total area of interest with some continuity being supplied 

 from one position of the center rectangle to an adjacent position by means of 

 the overlapping effect of the eight surrounding rectangles. This approach 

 allowed different size areas to be analyzed with equal accuracy and also 

 allowed for the development of a generalized program applicable to any area. 

 Besides the size of the rectangles, the relative depth to which the currents 

 were referenced, i.e. the level of no motion, and the time period over which 

 the currents were averaged were both variables which were specified in the 

 program. 



