APPENDIX H 

 WIND DEFORMATION PROCEDURE 



Assuming that the wind-stress components (t« ' , t^* ') 



are known in the stretched shelf coordinate system from the applica- 

 tion of a symmetric wind field model, the problem in part is to 

 identify a region for a given hurricane and coastline where it is 

 appropriate to alter these stresses to reflect the influence of land. 

 The proposed deformation equations are applied only at points which 

 are located within this region. Existing charts of hurricane winds 

 and the investigation by Graham and Nunn (1959) provide the basis for 

 the empirical deformation formulas. In this manner, the analytical 

 representation obviates the detailed input of a massive sequence of 

 digitized wind field data that conforms with the observations near 

 the coast as well as offshore. 



The wind-stress components, x s J SYM ^and x T J SYM \are 

 altered at a point for which Yj > Yq according to the relationship: 



T c* = T c* ' I.c > (H-l) 



S* f 



and 



(SYM) 



CI f ) , (H-2) 



where m is a constant chosen to be 2 and I_ is an influence 

 factor given by: 



I f = 1 - D £ [ (Y x - Y D )/\] 2 , (H-3) 



where R^ is a constant taken as the average radius to maximum winds 

 of the hurricane, Df is a distortion factor, Yq is the shortest 

 distance the point is from land, and Yj is the distance the 

 influence region extends from the coast relative to the point in 

 question (Figure H-l). In general, Yj should depend on Xq , the 

 distance the point in question is from a centrally located point along 

 the coast (x c ,y c ). This latter point is generally assigned the 

 coordinates of intersection of the hurricane track with the coastline. 

 From Figure H-l, the distances Xq and Yp are given by: 



X D = ± t (x s - x c ) 2 + (y s - y c ) 2 ] % , (H-4) 

 and 



