El Nino and La Nina

Normal Conditions:

• Southeast trade winds bring warm waterto the west pacific e.g Australia/Indonesia
• Air rises in low pressure systems over west pacific near Australia/Indonesia
• Walker Circulation cell
• Ocean surface currents take warm water away from West and brings them to the east
• Brings cold water up from below - upwelling of cold water in east pacific e.g. south America
• Warm water accumulates…