1. ENSO Impacts in Central Andes
El Niño (warm-phase ENSO) is typically associated with warm and sometimes drier conditions, leading to glacier retreat
low albedo bare ice is exposed to intense tropical sun at higher temperatures
La Niña (cold-phase ENSO) is typically associated with cool and sometimes wetter conditions, leading to glacier advance
high albedo fresh snow covers most glacier surfaces, cloud cover is increased, and temperatures are lower

2. Arctic Oscillation
What is the Arctic Oscillation and why is it important?

3. Arctic Oscillation
Seesaw variation in air pressure between the North Pole and middle latitudes
Associated changes in the horizontal air pressure gradient alter the speed of the band of winds aloft that blows counterclockwise around the Arctic
Impacts middle latitude winter weather and contributes to climate variability
Shifts between negative and positive phases
© AMS

4. Arctic Oscillation (AO)
“An atmospheric circulation pattern in which the atmospheric pressure over the polar regions varies in opposition with that over middle latitudes (about 45 degrees North) on time scales ranging from weeks to decades.” (NSIDC)
Also largely synonymous with the North Atlantic Oscillation (NAO)
Negative AO = colder air over mid-latitudes
Positive AO = warmer air over mid-latitudes

5. North Atlantic Oscillation
NAO Index varies significantly from one year to the next and from decade to decade
Record of the North Atlantic Oscillation (NAO) during winter through
© AMS

7. Arctic Oscillation (AO)
NCDC 2010

8. Accuweather 2004

9. Arctic Oscillation Links

10. NOAA 2011

11. Pacific Decadal Oscillation
“The Pacific Decadal Oscillation (PDO) is a long-lived El Niño-like pattern of Pacific climate variability” (Univ. of Washington 2011)
Decadal variations in Pacific SSTs and sea level pressure
Warm Phase
Cool Phase

12. Pacific Decadal Oscillation
Variations in the Pacific Decadal Oscillation (PDO) Index between warm phases (positive values) and cool phases (negative values),
© AMS

13. Madden-Julian Oscillation (MJO)
Large-scale coupling between atmospheric circulation and tropical deep convection

14. MJO Links

15. Warm Arctic Cold Continents Pattern
NSF 2010

17. El Niño-Southern Oscillation
North Atlantic Oscillation
Late 1970s
Climate Shift
Pacific Decadal Oscillation
“Decadal variations in teleconnections considerably complicate the interpretation
of climate change. Since the TAR, it has become clear that a small number of
teleconnection patterns account for much of the seasonal to interannual variability
in the extratropics” (Trenberth et al. 2007, Chapter 3 of IPCC Physical Science Basis)

18. Warm-phase of ENSO (El Niño) has accelerated tropical
Chacaltaya Glacier, Bolivia
Antizana Glacier 15, Ecuador
Warm-phase of ENSO (El Niño) has accelerated tropical
Andean glacier retreat since the late 1970s
Warm-phase ENSO
Glacier Recession in
Cord. Vilcanota, Peru
Francou et al. (2003)
Seimon et al. (2007)

19. Recession of the plateau glaciers on Mt
Recession of the plateau glaciers on Mt. Kilimanjaro in East Africa has been primarily a result of less precipitation and more sunshine in association with changes in atmospheric circulation.
Kaser et al. (2010)