 However, under some circumstances, tropical or subtropical cyclones may maintain or even increase their intensity for several hours in what is known as the brown ocean effect.This is most likely to occur with warm moist soils or marshy areas, with warm ground temperatures and flat terrain, and when upper level support remains conducive.El Niño (ENSO) shifts the region (warmer water, up and down welling at different locations, due to winds) in the Pacific and Atlantic where more storms form, resulting in nearly constant Accumulated Cyclone Energy (ACE) values in any one basin.