Atmo: El Niño

Question 1

Describe the El Niño process part 1

Answer 1

1) southern oscillation occurs
2) barometric pressure rises in Western Pacific (SEA) and falls in eastern Pacific (Peru, equator)
3) pressure gradient and trade winds weaken and reverse
4) warm water shifts eastwards, increasing water temps in eastern Pacific

Question 2

Describe the El Niño process part 2

Answer 2

1) the warm air above the sea rises and creates a low pressure at the surface, cooling adiabatically
2) diverges and moves towards western Pacific
3) air cools and sinks, creating high pressure at surface
4) subsidence of air leads to compression which leads to adiabatic heating
5) lowers RH
6) impedes condensation and cloud formation
7) warming of upper layers will cause a gentler ELR
8) stable atmosphere
9) drought in SEA

Question 3

Draw the El Niño diagram

Answer 3

Counter-clockwise direction
Top arrow: easterly counter flow
Bottom arrow: surface westerly wind
High pressure at western Pacific (SEA/Australia)
Low pressure at eastern Pacific (Peru, Ecuador)
Warm surface current going to Peru