how is the formation of an alluvial fan similar to the formation of a delta
River delta In both of these cases, depositional processes force redistribution of deposition from areas of high deposition to areas of low deposition. This results in the smoothing of the planform (or map-view) shape of the delta as the channels move across its surface and deposit sediment. Because the sediment is laid down in this fashion, the shape of these deltas approximates a fan. The more often the flow changes course, the shape develops as closer to an ideal fan, because more rapid changes in channel position results in more uniform deposition of sediment on the delta front. The Mississippi and Ural River deltas, with their bird's-feet, are examples of rivers that do not avulse often enough to form a symmetrical fan shape. Alluvial fan deltas, as seen by their name, avulse frequently and more closely approximate an ideal fan shape.
Convection cell A convection cell is most notable in the formation of clouds with its release and transportation of energy. As air moves along the ground it absorbs heat, loses density and moves up into the atmosphere. When it is forced into the atmosphere, which has a lower air pressure, it cannot contain as much fluid as at a lower altitude, so it releases its moist air, producing rain. In this process the warm air is cooled; it gains density and falls towards the earth and the cell repeats the cycle.