So far, we have only discussed upwelling in terms of a process that occurs along the coast. However, marine upwelling will occur anywhere that the circulation pattern results in a surface "deficit" of water! Along the coast this deficit occurs when the wind drives a current offshore, causing water to rise up from below to fill the void. It's important to keep in mind though that this is just one type of upwelling - other processes can result in the same type of effect away from the shore!

To illustrate this, let's consider a type of upwelling illustrated by the last option from the previous images, Equatorial Upwelling.