What is it South America Southeast Asia Australia North America Normal conditions in equatorial Pacific Ocean Warm water in the w estern Pacific C old water in the eastern ID: 785632
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Slide1
El
Ni
ñ
o–Southern
Oscillation (ENSO
):
What is it?
Slide2South America
Southeast Asia
Australia
North America
Normal
conditions
in equatorial Pacific OceanWarm water in the western PacificCold water in the eastern Pacific
Source: NOAA/CPC
Slide3Normal
conditions
in equatorial
Pacific
Ocean
Deep convective storms and heavy rain concentrated over warm water in western PacificWarm water provides “fuel” for storms
South AmericaSoutheast AsiaAustraliaNorth AmericaSource: NOAA/CPC
Slide4Normal
conditions
in equatorial
Pacific
OceanWalker Circulation is in place
Rising air over western Pacific, sinking motion over eastern Pacific
Winds: easterly (east to west) at surface, westerly (west to east) aloft South AmericaSoutheast AsiaAustraliaNorth AmericaSource: NOAA/CPC
Slide5Normal
conditions
in equatorial
Pacific
OceanUpwelling brings cold water to the surface near the western coast of South America
South America
Southeast AsiaAustraliaNorth AmericaSource: NOAA/CPC
Slide6El Ni
ño
conditions
in equatorial Pacific Ocean
Warm water spreads eastward across the Pacific
South America
Southeast AsiaAustraliaNorth AmericaSource: NOAA/CPC
Slide7El Ni
ño
conditions
in equatorial Pacific Ocean
Convective storms shift eastward into central and eastern North Pacific,
remaining fixed over warm waterLocation of convective storms varies from event to event
South AmericaAustraliaNorth AmericaSource: NOAA/CPCSoutheast Asia
Slide8El Ni
ño
conditions
in equatorial Pacific Ocean
Walker Circulation weakens
Surface easterlies weaken or become westerly
Upward motion develops over central/eastern PacificSouth AmericaAustraliaNorth AmericaSource: NOAA/CPC
Southeast Asia
Slide9El Ni
ño
conditions
in equatorial Pacific Ocean
Upwelling decreases in eastern Pacific and warm water reaches coast of South America
South America
AustraliaNorth AmericaSource: NOAA/CPCSoutheast Asia
Slide10La Ni
ña
conditions
in equatorial
Pacific
OceanBig
difference in sea surface temperatures between western and eastern PacificWarm water in western Pacific, cold water in eastern PacificSouth AmericaAustraliaNorth AmericaSource: NOAA/CPC
Southeast Asia
Slide11La Ni
ña
conditions
in equatorial Pacific Ocean
Convective storms shift westward, remaining fixed over warm water
Source: NOAA/CPC
South AmericaAustraliaNorth AmericaSoutheast Asia
Slide12La Ni
ña
conditions
in equatorial Pacific Ocean
Walker Circulation strengthens
Source: NOAA/CPC
South AmericaAustraliaNorth AmericaSoutheast Asia
Slide13La Ni
ña
conditions
in equatorial Pacific Ocean
Upwelling increases in eastern Pacific, and water is cold along coast of South America
Source: NOAA/CPC
South AmericaAustraliaNorth AmericaSoutheast Asia
Slide14Tracking the evolution of ENSO
Highly variable with lots of fluctuations; no regular cycle
El Ni
ñ
o or La Niña events
typically last 9–12 months, sometimes even longer
On average, El Niños and La Niñas occur every 3–5 yearsImpacts on ocean and atmosphere usually most significant in Northern Hemisphere
Sea surface temperature departure from average over central equatorial Pacific – a commonly used ENSO measurement
El Ni
ño
La Ni
ña
Source: NOAA/CPC
Slide15Ocean temperatures for past
El Ni
ño and La Niña events
Source: NOAA/CPC
Strong
El Ni
ño eventStrong La Niña event
Slide16Current Conditions
Sea surface temperature anomalies
3–30 January 2016
Warmer than normal
Cooler than normal
Source: NOAA/CPC
Slide17Fewer
clouds/rain than normal
More
clouds/rain than normal
Current Conditions
Source: NOAA/CPC
Outgoing longwave radiation anomalies3–28 January 2016
Slide18Links to animations
Recent evolution of Pacific sea surface temperatures:
http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/enso_update/sstanim.shtml
Comparison between 1997 and 2015 sea surface temperatures:
https://youtu.be/
whsQbIwWjBo
Slide19Impacts of El Niño on
wintertime
weather over the U.S.
Slide20El Niño’s
typical impact
on
wintertime weather over the U.S.
Warmer
than normal across northern U.S.
Wetter than normal across the southern U.S.Drier than normal over northeastern U.S.Source: NOAA/Climate.gov
Slide21How
has
El
Niño
affected the U.S. in past winters?
Precipitation relative to normal
Temperature relative to normalCooler
Warmer
Drier
Wetter
1982–1983
1997–1998
Source: NOAA/ESRL
Slide22What about this winter?
It was
super warm in December 2015 over the U.S
….and across the globe
Temperature relative to normal
Cooler
WarmerSource: NOAA/ESRL
Global
temperature time series for
all Decembers on record
1880
2015
Source: NOAA/NCDC
Warmest December on record for Albany, for New York State, for the U.S., and for the entire globe!
Slide23Precipitation relative to normal
Drier
Wetter
…and it has been
raining/snowing
a lot in some areas
Precip anomaly for Nov 2015–Jan 2016Source: NOAA/NWSWhat about this winter?
Slide24Source: National Drought Monitor
Drought conditions
in early
October
2015
Slide25Current drought conditions
Source: National Drought Monitor
Drought has improved in many areas in the West!