Convection is the process in which heat is transferred by movement of a heated fluid such as air or water. Natural convection results from the tendency of most fluids to expand when heated so it becomes less dense and rise above.
For example- In a pot of water on a stove the liquid t bottom is heated by conduction. The hot water has lower density and it rises above pushing the cold water downwards so it gets heated.
Should be just 2 km. - 2 km would mean it is moving in the opposite direction which come to think of it may be fine. You really can't tell.
