Climate Variability and Climate Change

in the U.S.-Mexico Border Region

Upper San Pedro PartnershipTechnical Committee Meeting

Cochise College – Sierra Vista, Arizona – July 26, 2007

Gregg GarfinClimate Assessment for the SouthwestInstitute for the Study of Planet EarthUniversity of Arizona

Atmospheric Circulation: Winter

H

Mike Crimmins, University of Arizona

Atmospheric Moisture: Winter

DRY

MOIST

Mike Crimmins, University of Arizona

Atmospheric Circulation: Winter

H

Mike Crimmins, University of Arizona

Atmospheric Circulation: Summer

BermudaHigh

H

Mike Crimmins, University of Arizona

Atmospheric Moisture: Summer

DRY

MOIST

Mike Crimmins, University of Arizona

75° N

60° N

45° N

30° N

15° N

0°

15° S

30° S 30 ° E

90° N

30 ° W 60 ° W 90 ° W 120° W 150° W 180° W 150° E 120° E 90 ° E 0 °

PPacificDDecadalOOscillation

AAtlanticMMultidecadalOOscillation

EEl NNiño SSouthern OOscillation

Persistent Circulation Influences on Western US

Slide courtesy of Julio Betancourt, USGS

• Redistribute energy, moisture• Persistent changes: Duration 1-3 years• Recur every 2-7 years

El Niño-Southern Oscillation (ENSO)

warm

cool

cool

warm

~ ~

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

0

2

4

6

8

10

12

14

-3.0 -2.0 -1.0 0.0 1.0 2.0 3.0

Average SOI (Jun-Nov)

Win

ter

Pre

cip

ita

tio

n (

No

v-A

pr)

(i

nc

he

s)

El Niño

Neutral

La Niña

Climate Division 7Southeastern Arizona

1895-2002

Pacific Decadal Variability

• Discovered in 1990s• Occurs every 20-30

years• Mechanism likely

– ENSO– Kuroshio Current– Aleutian Low

Courtesy of N. Mantua – University of WashingtonMantua et al., 1997 Bulletin of the American Meteorological Society

91 84

82

8779 78

78

Negative PDO

113117

131

115123 119

120

Positive PDO

AZ PDO (Oct.-Sept.) Precipitation % Average

Based on Maxwell and Holbrook, NWS Tucson

http://www.ncdc.noaa.gov/oa/climate/research/teleconnect/teleconnect.html

http://www.ncdc.noaa.gov/oa/climate/research/teleconnect/teleconnect.html

Shift toLow Index?

Positive AMO Phase

Atlantic Multidecadal Oscillation - AMO

Slide courtesy of Greg McCabe, USGS

• West: Warm, dry, high pressure• Associated with 1950s and late-1500s droughts

Pacific negative + Atlantic positive

.

McCabe et al., 2004 Proceedings of the National Academy of Sciences

.

Drought Frequency % (25 = expected)

high drought frequencylow drought frequency

OBSERVED CHANGES

Global Energy Balance

From http://www.bom.gov.au

http://www.grida.no/climate/vitalafrica/english/09.htm

380

Most rapid change in the last 10,000 years

280

CO2 Changes

http://www.grida.no/climate/vital/02.htm

http://lwf.ncdc.noaa.gov/oa/climate/research/anomalies/anomalies.html

Western Regional Climate Center

June-May Temperature

Cochise County

Western Regional Climate Center

June-May Precipitation

Cochise County

Courtesy of Noah Knowles, USGS

Trends in Nov-Mar Snowfall Fraction

More Rain, Less Snow More Snow, Less Rain

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

Economic emphasis

A1B Balanced energy

A2 fragmente

dA1FI Fossil-fuel Intensive

A1T high-Tech renewables

Environmental emphasis B1 B2 local

IPCC 3rd Assessment Report

Data: IPCC 4th Assessment

IPCC 4th Assessment: Working Group I, Chapter 11, Regional Projections

Annual Temperature: End of 21st Century

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

Diffenbaugh et al., 2005Proceedings of the National Academy of Science

Increased Length of Average Heat Wave (days)

4 models and A2 “Business as Usual” emissions scenarios in a Regional Climate Model

2071-2095Minus1961-1985

Diffenbaugh et al., 2005Proceedings of the National Academy of Science

Annual Evapotranspiration

A2

Diffenbaugh et al., 2005Proceedings of the National Academy of Science

Increased Fraction of Extreme Precipitation

A2

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 likelyDecreased 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 GarfinClimate Assessment for the SouthwestInstitute for the Study of Planet Earth

gmgarfin@email.arizona.edu520-622-9016

www.ispe.arizona.edu/climashttp://www.climate.noaa.gov/cpo_pa/risa/