# Coriolis effect and curl

1. Oct 24, 2014

### Keru

Two quick questions. Does the Coriolis effect mean that in the northern hemisphere the curl will always have a negative value and in the southern hemisphere a postive one? Is the curl in the eye of the cyclones equal to zero?
Thanks.

2. Oct 24, 2014

### Matterwave

The Coriolis effect is proportional to $-2(\vec{\omega}\times\vec{v})$ where $\vec{\omega}$ is pointing up out of the North pole, along the axis of Earth's rotation. Whether this curl is positive or negative depends on the vector $\vec{v}$ and can not be generalized to "northern vs southern hemisphere" effects. However, if something (say a bullet) is moving initially along a straight line in the Northern hemisphere, its trajectory will be deflected (by the Coriolis force) in a clockwise direction, while in the Southern hemisphere the trajectory would be deflected in a counter-clock-wise direction.

3. Oct 24, 2014

### Meir Achuz

By "curl" do you mean $\nabla\times$ or something else?

4. Oct 24, 2014

### Matterwave

Haha! I had a brain fart and associated a cross product $\vec{\omega}\times\vec{v}$ as a curl. Now I'm not sure what the OP is asking.

5. Oct 25, 2014

### Keru

Yes i meant ∇×. Sorry im not english native speaker, searched for the translation and that's the best i had.