Barrons AP Environmental Science

Figure  2.13    The development of  El  Niño

Source: National    Weather Service 

Figure  2.14    El  Niño    effects (December–February) Upwellings

Upwellings occur when prevailing winds, produced through the Coriolis effect
and moving clockwise in the Northern Hemisphere, push warmer, nutrient-poor
surface waters away from the coastline. This surface water is then replaced by