SIO 217C: Climate
Spring 2014
Climate Variability Discussion Questions
1. Explain how the atmosphere and ocean work together to produce “normal” conditions over
the equatorial Pacific Ocean. Explain how the atmosphere and ocean work together to
produce El Niño conditions over the equatorial Pacific Ocean.
2. Most regions of the world experience an annual cycle of precipitation (one maximum and
one minimum per year), but some equatorial regions experience a semi-annual cycle of
precipitation (two maxima and two minima per year). Why?
3. Explain why the positive phase of the Pacific Decadal Oscillation (colder average sea surface
temperature in the central North Pacific and warmer sea surface temperature along the coast
of North America) is associated with a stronger Aleutian Low.
4. Explain why the positive phase of the North Atlantic Oscillation (lower pressure than
average over Iceland and higher pressure than average over the Azores) is associated with
colder than average sea surface temperature in the western midlatitude North Atlantic and
eastern subtropical North Atlantic with warmer than average sea surface temperature in
between.
Difficult Question
5. Aerosol particles became increasingly abundant in the North Atlantic sector from the 1950s
to the 1980s as industry and population increased in North America and Europe. After the
1980s, aerosol particles decreased due to clean air laws. Explain how radiative forcing by the
aerosol particles could possibly be responsible for the decline and recovery in precipitation
over the Sahel region of Africa during the same time period.