A listing and fuller explanation of the programs XTRACT and DYFIT can be found in Appendices 



AandB. 



THE SOUTHERN CALIFORNIA BIGHT 



A region from 32° N to 3? N and from 117 1V to 122°W' off the coast of Southern CaUfornia 



was chosen as the area to test the applicability of the above described method. There were several 



reasons for choosing this particular area: 



o There have been many hydrographic surveys in the area, so there should be a sufficient 

 amount of data; 



o Qualitatively the currents are well understood showing a definite seasonal dependence; 



o The water is deep so that the geostrophic currents should be meaningful. 



A standard hydrographic data tape for the above area was obtained from NODC. After initial 

 preparation of the data with the XTRACT program the DYFIT program was run with rectangles 

 equal to 1° of latitude by 1° of longitude. Also as most of the hydrographic data extended only to 

 500 meters, 500 meters was chosen as the reference level, tlius enabling the utilization of most 

 of the data. While 500 meters may appear to be somewhat shallow for a reference level, cross- 

 checking wherever possible showed no significant differences in surface velocities when 1000 

 meters was used as a reference level. The spline fit was evaluated at the center of rectangles 1/4 x 

 1/4 °, 1/2° X 1/2 ° and 1° x 1 ° on their sides. As it turned out the current structure was such that 

 there were no areas that required rectangles smaller than 1/2 x 1/2 in order to be able to cha- 

 racterize the currents. The data was of sufficient volume to be grouped by months for analysis. 



The results of the analysis are depicted in the twelve chartlets in Figures 2-13 with the current 

 directions given in degrees true and the speed in knots. The currents are evaluated at the center 

 of the rectangle. The analysis indicates that the average geostrophic velocities in the Southern 

 California Bight are relatively small, with maximum speeds of only approximately 0.2 knot. 



4 



