Modeling of the propagating wave would be incomplete without properly updating the values of and
after each boundary reflection.
Following Bellhop the method used to update the values is given by:

(5.8) 
where and stand for the values before reflection,
and and stand for the values after.
The correction is given by the expression

(5.9) 
where stands for the value of sound speed at the boundary,
and
corresponds to the boundary tangent,
is the boundary normal and
is the sound speed gradient;
additionally,
and
stand for the slowness and normal slowness,
which can be written as
all parameters should be calculated at the reflection point.
Orlando Camargo Rodríguez
20120621