controversial. However, taking into account that wind speeds 

 associated with hurricanes are not steady or uniform, k is taken as a 

 function of wind speed. 



The surface wind stresses are computed at every time step using 

 linear interpolated positions of the hurricane center which are given 

 at 6 h intervals, except for the case of hurricane Car la simulation 



o 



which will be discussed later. A constant inflow angle of 20 is 

 used to rotate the surface stress vector before the components are 

 computed . 



For the bottom stress, W is the depth averaged lower layer 

 current velocity, i.e. 



Tb=«|V2lV2. (52) 



where IV2I is the magnitude of the depth averaged lower layer 

 current. A constant value of 2.5 x 10"^ is assumed for the 

 coefficient k. The lower layer current, IV2I is given in terms of 

 the modal velocities by the relation 



V2 = (l/D)Ve - (l/H2)Vi, (53) 



where Vg and Vj_ are the external and internal velocity vectors, 

 respectively. 



The bottom stress for the external mode computation at odd time 

 steps is coded as 



Tj3 = 2.5 X 10"3At{[(l/D)Ug(I,J) - (l/H2)Ui(I,J)]2 



+ [(l/D)Vg(i,J) - (l/H2)VI,J)]2}^{-(l/H2)Ui(I,j)}. (54) 



Upon substituting (53) in (52) both Ug and Uj^ from the previous time 



26 



