# How to compute the moisture flux convergence at a grid point? [duplicate]

I have $u$-wind, $v$-wind and specific humidity. I would like to compute moisture flux convergence at a grid point. So I need to compute the value of $q(\frac{du}{dx} + \frac{dv}{dy})$

My question is how to compute $\frac{du}{dx}$ and $\frac{dv}{dy}$ from $u$-wind and $v$-wind at grid point $(x,y)$?

• What is $u$-wind and $v$-wind? – Yashas Feb 9 '17 at 8:25
• u is the zonal velocity and v is meridional velocity. – Kay Feb 9 '17 at 8:32