Wind component horizontal advection

The $u$-momentum flux-form horizontal advection term is expressed as

$\displaystyle \nabla\cdot{\left( {\bf V}\mu u\right)}_{i,j} =
\Big\lbrack
{\ove...
...verline u^y}_{i,j+1}
-{\overline V^x}_{i,j}{\overline u^y}_{i,j}
\Big\rbrack /d$ (129)

and the $u$-momentum flux terms are expressed as

$\displaystyle {\overline U^x}_{i,j}$ $\displaystyle = \left( U_{i+1,j} + U_{i,j}\right)/2$ (130)
$\displaystyle {\overline V^x}_{i,j}$ $\displaystyle = \left( V_{i-1,j} + V_{i,j}\right)/2$ (131)

where the horizontal velocity components are interpolated using

$\displaystyle {\overline u^x}_{i,j}$ $\displaystyle = \left( u_{i,j} + u_{i+1,j} \right)/2$ (132)
$\displaystyle {\overline u^y}_{i,j}$ $\displaystyle = \left( u_{i,j} + u_{i,j-1} \right)/2$ (133)

The $v$-momentum equation advection is written in finite difference form using the same method as above.