Material for Exam 2 starts HERE

1
Material for Exam 2 starts HERE
2
Oceanic Currents

• Surface Currents
• Cold high latitude
• Warm low latitude
• Gyres circulate in which directions?

3
Major Ocean Currents
Peru Current
Figure 6.22
4
Oceanic Currents

• Deep Currents
• Thermohaline circulation
• Distributes energy
• Effects of global warming?

5
Deep Currents
Figure 6.23
6
ENSO events

• ENSO events are a disruption of the
  ocean-atmosphere system in the tropical Pacific
• El Nino Southern Oscillation
• El Nino ocean
• Southern Oscillation atmosphere

7
El Niño

• Changes in pressure patterns
• Changes in wind patterns
• Mainly concentrated in the Pacific Ocean
• Measured using Southern Oscillation Index
• Differences in pressure observed in Tahiti and
  Darwin, Australia
• Combined to form ENSO
• Affects weather globally

8
Buoys
9
El Niño
10
Impacts of ENSO Events

• Marine environments
• Atlantic hurricanes
• Global precipitation patterns
• Wildfires

11

• Australia-Drought and bush fires
• Indonesia, Philippines-Crops fail, starvation
  follows
• India, Sri Lanka-Drought,fresh water shortages
• Tahiti-6 tropical cyclones
• South America-Fish industry devastated
• Across the Pacific-Coral reefs die
• Colorado River basin-Flooding, mud slides
• Gulf states-Downpours cause death, property
  damage
• Peru, Ecuador-Floods, landslides
• Southern Africa-Drought, disease, malnutrition

12
El Niño
13
ENSO

• When high and low pressure systems exist in some
  locations, they not only impact local weather
  conditions, but also influence the overall size,
  shape, and position of the entire Rossby wave
  pattern
• Teleconnections relationship between weather or
  climate patterns at two widely separated locations

14
ENSO
15
ENSO

• Occurs once every 3 to 5 years (but varies)
• Is regulated by PDO
• Switch to PDO warm phase in 1999 appears to have
  dampened ENSO
• Major ENSO events in last 25 years 19821983,
  19861987, 19911993, 19971998, 20022003
• 19971998 was so intense, it disrupted global
  weather

16
Normal
17
Normal Year
18
ENSO
19
ENSO
20
ENSO Year
21
La Nina

• El Niño warm phase, La Niña cool phase
• La Niña brings extreme normal conditions
• Not all El Niño events are followed by La Niña
  events
• La Niña events increase wildfires in the SE and
  Atlantic hurricanes

22
La Nina