80 

 70 

 60 

 ■50 

 40 



UJ 



H SO 



< 



^70 



z 

 ^ 60 



< 

 a 



70 

 60 



70 

 60 



80 

 70 



O lO 20 30 40 SO 60 70 

 RAIN IN MM 



lO 20 30 40 50 60 70 

 RAiN IN MM 



Fig. 47. Examples of the Method Used in Constructing the 

 Joint Functional Regression Diagrams 



(a) The original data. For each of the temperatures shown on the graphs, 

 the mean spawn date for all the records at these temperatures has been 

 plotted against the rainfall. Lines have been drawn freehand to lie as evenly 

 as possible among the points 



(b) For each 10 mm of rainfall, as indicated on the graphs, points have 

 been plotted against each degree, as found from graph (a). 



(c) For each degree, as indicated on the graphs, points have been plotted 

 against each 10 mm of rainfaU, as found from graph (h). The result is a 

 smoothed version of (a), in which the shape of the curves has been modified 

 by taking account, not only of the points along each line, but of the shape of 

 neighbouring lines as well. Note the reduction of the scatter, and the 

 appearance of a consistent family of lines. 



(d) The final joint functional regression diagram. Using graph (c), the 

 coordinates, rainfall and temperature, for each year day, at five day intervals 

 from 60 to 80, have been foimd. The plotted points have been joined and 

 form the isophenes. 







.^ 



190 





