I assume the variable "L" defined in parameters has to be used instead of "l" inside the for loop.
The error you are getting at this line:
plot ((th0:dth:thl) , wbd , (th0:dth:thl) , albd/100 ,'lineWidth', 2);
Now, the error you are getting is because the plot takes two vectors:
a. (th0:dth:thl) of dimension 1*101 double
b. wbd of dimension 1*260 double
You must have same size of vectors to plot. Refer this for more on plot function.
Hope this helps!