ATOC 185 Lecture Notes - Lecture 6: Walker Circulation, Wind Shear, Reinsurance
8 Jun 2018
School
Department
Course
Professor
El
Niño
–
Week
6
We
have
all
been
affected
by
El
Niño
Impacts
depend
on
where
on
the
globe
you
are
Introduction
- Change in ocean currents that lead to warming in waters of equatorial east Pacific
- Warming can have significant impacts on weather across large parts of globe
-Also results in most well-known atmospheric teleconnection pattern (Southern Oscillation)
-Able to correlate weather at 2 places on globe that aren’t close to each other
-Ex. Correlating weather in Montreal and Vancouver
History
- Strong El Nino sparked famine in 1789-93 in Europe which sparked French Revolution
- Has historical significance
-1892 – Captain Camilo Carrillo told Geographical society congress in Lima that Peruvian sailors
named warm northerly current El Niño because it was most noticeable around Christmas
-Whenever this warming happened, people could expect certain weather conditions around
globe
Background
-Along West Coast of major continents, there tends to be a cold surge – cold currents that flow
along coast
- East side – much warmer waters
- What drives patterns of cold and warm? Why are there warmer temperatures along east coast
of continents and vice versa?
1. Wind Patterns
a. Easterly and Westerly Winds
i. Blow West to East in mid latitudes, E → W in low latitudes
b. True in both hemispheres
c. Easterlies turn to Westerlies
d. Along western coasts of continents, current is going from pole to equatorial
regions – cold
currents
down
California
and
coast
of
South
America
i. Arctic to tropical regions on Western sides of continents
ii. Winds bring warm waters North on Eastern sides of continents
2. The Ocean Thermocline
a. The way temperatures change with depth
b. Ex. Hurricanes break up colder temperatures from underneath, causing
upwelling, reducing strength of hurricane
i. Wind pushes away and replaces warm water on surface with cold water
Document Summary
Impacts depend on where on the globe you are. Warming can have significant impacts on weather across large parts of globe. Also results in most well-known atmospheric teleconnection pattern (southern oscillation) Strong el nino sparked famine in 1789-93 in europe which sparked french revolution. 1892 captain camilo carrillo told geographical society congress in lima that peruvian sailors named warm northerly current el ni o because it was most noticeable around christmas. Whenever this warming happened, people could expect certain weather conditions around globe. What drives patterns of cold and warm? . Why are there warmer temperatures along east coast: wind patterns i. Cold currents down california and coast of south america. Warm water is pushed towards western pacific from easterly winds. Warmest water is in western pacific ocean because trade winds are pushing all surface warm water towards indonesia, philippines, australia, new zealand. Amount of evaporation that takes place is directly associated with water temperature.
