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Climate Variability and
Climate Change
in the U.S.-Mexico
Border Region
Upper San Pedro Partnership
Technical Committee Meeting
Cochise College – Sierra Vista, Arizona – July 26, 2007
Gregg Garfin
Climate Assessment for the Southwest
Institute for the Study of Planet Earth
University of Arizona
Atmospheric Circulation: Winter
H
Mike Crimmins, University of Arizona
Atmospheric Moisture: Winter
MOIST
DRY
Mike Crimmins, University of Arizona
Atmospheric Circulation: Winter
H
Mike Crimmins, University of Arizona
Atmospheric Circulation: Summer
H
Bermuda
High
Mike Crimmins, University of Arizona
Atmospheric Moisture: Summer
DRY
MOIST
Mike Crimmins, University of Arizona
Persistent Circulation Influences
on Western US
90 ° N
75 ° N
60 ° N
Atlantic
Multidecadal
Oscillation
Pacific
Decadal
Oscillation
45 ° N
30 ° N
15 ° N
El Niño Southern Oscillation
0°
15 ° S
30 ° S °
90 E
120 ° E
150 ° E
180 ° W
150 ° W
120 ° W
90 ° W
60 ° W
Slide courtesy of Julio Betancourt, USGS
30 ° W
0°
30 ° E
El Niño-Southern Oscillation (ENSO)
~
~
cool
warm
warm
cool
• Redistribute energy, moisture
• Persistent changes: Duration 1-3 years
• Recur every 2-7 years
Slide courtesy of Greg McCabe, USGS
El Niño: Winter Effects U.S.
• Increased ephemeral channel recharge
Source: NOAA Climate Prediction Center
http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/ensocycle/winter25%25.gif
La Niña: Winter Effects U.S.
• Drought circulation pattern
Source: NOAA Climate Prediction Center
http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/ensocycle/winter25%25.gif
Winter Precipitation (Nov-Apr)
(inches)
14
12
10
8
6
4
2
0
El Niño
-3.0
Neutral
La Niña
-2.0
-1.0
0.0
1.0
Average SOI (Jun-Nov)
Climate Division 7
Southeastern Arizona
1895-2002
2.0
3.0
Pacific Decadal Variability
• Discovered in 1990s
• Occurs every 20-30
years
• Mechanism likely
– ENSO
– Kuroshio Current
– Aleutian Low
Courtesy of N. Mantua – University of Washington
Mantua et al., 1997 Bulletin of the American Meteorological Society
AZ PDO (Oct.-Sept.) Precipitation
% Average
Negative PDO
84
91
Positive PDO
113
82
117
131
115
87
79
78
123
78
119
120
Based on Maxwell and Holbrook, NWS Tucson
http://www.ncdc.noaa.gov/oa/climate/research/teleconnect/teleconnect.html
Shift to
Low
Index?
http://www.ncdc.noaa.gov/oa/climate/research/teleconnect/teleconnect.html
Atlantic Multidecadal Oscillation - AMO
Positive AMO Phase
• West: Warm, dry, high pressure
• Associated with 1950s and late-1500s droughts
Slide courtesy of Greg McCabe, USGS
Pacific negative + Atlantic positive
Drought Frequency % (25 = expected)
.
high drought frequency
low drought frequency
.
McCabe et al., 2004 Proceedings of the National Academy of Sciences
OBSERVED CHANGES
Global Energy Balance
From http://www.bom.gov.au
http://www.grida.no/climate/vitalafrica/english/09.htm
CO2 Changes
380
280
Most rapid change in the last 10,000 years
http://www.grida.no/climate/vital/02.htm
http://lwf.ncdc.noaa.gov/oa/climate/research/anomalies/anomalies.html
Cochise County
June-May Temperature
Western Regional Climate Center
Cochise County
June-May Precipitation
Western Regional Climate Center
Trends in Nov-Mar Snowfall Fraction
More Rain, Less Snow
More Snow, Less Rain
Courtesy of Noah Knowles, USGS
Dramatic Warming Episodes
Losses of 30-60%
Stewart et al. 2005 Journal of Climate
Stewart et al. 2005 Journal of Climate
Stewart et al. 2005 Journal of Climate
PROJECTIONS
GCM
• Models, based on physics
– Atmosphere, ocean
• Some processes must be estimated,
scaled to large regions
• Processes tuned and validated using
historical data
• Models driven by forcing factors
– Solar, volcanic, GHGs, aerosols (particles)
Scenario descriptions
Global integration
Regionalism
A1B
Balanced energy
Economic
emphasis
A1FI
Fossil-fuel Intensive
A2
fragmented
A1T
high-Tech renewables
Environmental
emphasis
B1
IPCC 3rd Assessment Report
B2 local
Data: IPCC 4th Assessment
Annual Temperature: End of 21st Century
IPCC 4th Assessment: Working Group I, Chapter 11, Regional Projections
Annual Precipitation: End of 21st Century
IPCC 4th Assessment: Working Group I, Chapter 11, Regional Projections
Atmospheric Circulation: Winter
H
Atmospheric Circulation: Winter
H
A1B
A1B
A1B
A1B
Heat Waves
Increased
Length of
Average
Heat Wave
(days)
4 models and A2
“Business as Usual”
emissions scenarios in
a Regional Climate
Model
2071-2095
Minus
1961-1985
Diffenbaugh et al., 2005
Proceedings of the National Academy of Science
Annual Evapotranspiration
A2
Diffenbaugh et al., 2005
Proceedings of the National Academy of Science
Increased Fraction of Extreme Precipitation
A2
Diffenbaugh et al., 2005
Proceedings of the National Academy of Science
What does global warming have in
store for El Niño?
• Latest word: Study
comparing 20 different
climate models
• No clear consensus!
• Models still do not
simulate El Niño well…
• “Best” models showed
smallest changes
More La
Niña-like
More El
Niño-like
Collins, 2005, Climate Dynamics
Climate Change Water Challenges in the
Arizona-Sonora Border Region
Increased temperatures: very likely
Decreased precipitation: likely
Potential direct impacts and concerns:
• Decreased surface water supply reliability
• Increased evaporation
• Reduced minimum flows for fish
• Earlier peak flow timing
• Greater likelihood of extreme events: drought, flood
Incorporating Climate Into Streamflow Prediction
• Statistical models (PPT, SWE, Streamflow)
• Historical data are assumed to be a sample of
future events
• Ensemble streamflow prediction (ESP)
• Conceptual hydrologic models
• Soil moisture accounting, Snow model
• Current basin initial states
• Multiple meteorological inputs
• TEM, PPT, Estimated Upstream flow
• Probabilistic distribution of future events, daily
data aggregated to seasonal water volume
Franz et al., Journal of Hydrometeorology, 2005
Incorporating Climate Into Streamflow Prediction
• Force models with data adjusted for seasonal
outlook terciles, or ENSO, PDO, AMO phases
• Assumptions
• Historical data are representative of future states
• Accurate understanding of processes and their
sensitivities to climate variations
Dennis Lettenmaier, University of Washington
Gregg Garfin
Climate Assessment for the Southwest
Institute for the Study of Planet Earth
[email protected]
520-622-9016
www.ispe.arizona.edu/climas
http://www.climate.noaa.gov/cpo_pa/risa/