El NinoLa Nina

1
El Nino--La Nina Consequences for temperatures
and precipitation on S. Vancouver Island Roy
HyndmanWIGA May, 2009 Controls of temperature
variability and year to year growing degree days
on S. Vancouver Island Superimposed on
long-term global warming
warm
cool
2008
1982
2
Global warming over long term--- but
Follows atm. CO2 incr.
WIGA 2009
3
Warming in Pacific Northwest Avg. 16 sites,
1900-2008 1oC But short-term variability El
Nino, sunspot activity, heat island, etc.1.5C
by the 2030s 3.0C by the 2050s (i.e., N.
California)
2.0
1.0
0
-1.0
0
oC
1900
2000
Year
WIGA 2009
4
WIGA conference May, 2009
Major changes in pattern of equatorial
currents irregular 3-7 years
El Niño E to W Trade winds weaken or
reverse Pacific Northwest is usually drierand
warmer than average La Niña Trade winds
strengthen Pacific Northwest is usually
wetterand cooler than average El Niño The
Little Boy or Christ child commonly arrives
about ChristmasLa Niña The Little Girl in
Spanish
5
Trade Winds
Warm-wet
Cool-dry
6
El Nino--La Nina Ocean currents and temperatures
7
Warm El Nino
Cold La Nina
Degree Days/year Victoria
8
WIG
180 mm
130 mm
G H. Taylor, Tye Parzybok, 1997
Winter precipitation (Near Portland OR)
9
7.8 C
5.5 C
Mean Air Temperature (Near Portland OR)
WIGA 2009
10
WIGA 2009
11
NOAA 9 April 2009 Atmospheric and oceanic
conditions during March 2009 continued to reflect
weak La Niña conditions. Based on current
observations, recent trends, and model
forecasts, a transition to ENSO-neutral
conditions is expected during April 2009.
Update April 25 Based on recent trends in the
observations and model forecasts, a transition to
ENSO-neutral conditions will continue.
warm
cool
2008
2009
Summer
Spring 2008
Spring 2009
Fall 2008
25 April
12
Van Is.
13
Computer model forecasts from climate
modelling groups around the world
Avg.
Start forecasts
Today
Nov
March
May
July
Sept
2009
2010
14
Forecasts The mean (heavy blue line) predicts La
Niña will end during April 2009, followed by
positive SST anomalies during the last half of
2009.
warm
cool
Today
2010 Jan
2009 Jan
July
Oct
April
July
Oct
15
Final notes

• El Nino - La Nina conditions change
• slowly over months
• Forecasts good for 1 month
• fair for 2-3 months
• not very reliable for 6 months
• 2. Increasing rate of global warming predicted,
• but much short-term climate variability, El
  Nino-La Nina etc.
• Growing degree days From 850-1100C?