Climate Variability and Climate Change in the U

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 cool • Redistribute energy, moisture • Persistent changes: Duration 1 -3 years • Recur every 2 -7 years Slide courtesy of Greg Mc. Cabe, 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/winter 25%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/winter 25%25. gif

Climate Division 7 Southeastern Arizona 1895 -2002

Pacific Decadal Variability • Discovered in 1990 s • 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 91 113 82 78 117 131 115 87 79 Positive PDO 78 123 119 120 Based on Maxwell and Holbrook, NWS Tucson

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

Shift to Low Index? http: //www. ncdc. noaa. gov/oa/climate/research/teleconnect. html

Atlantic Multidecadal Oscillation - AMO Positive AMO Phase • West: Warm, dry, high pressure • Associated with 1950 s and late-1500 s droughts Slide courtesy of Greg Mc. Cabe, USGS

Pacific negative + Atlantic positive Drought Frequency % (25 = expected) . high drought frequency low drought frequency. Mc. Cabe 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

CO 2 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. 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

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 A 1 B Balanced energy Economic emphasis A 1 FI Fossil-fuel Intensive A 2 fragmented A 1 T high-Tech renewables Environmental emphasis B 1 IPCC 3 rd Assessment Report B 2 local

Data: IPCC 4 th Assessment

Annual Temperature: End of 21 st Century IPCC 4 th Assessment: Working Group I, Chapter 11, Regional Projections

Annual Precipitation: End of 21 st Century IPCC 4 th Assessment: Working Group I, Chapter 11, Regional Projections

Atmospheric Circulation: Winter H

A 1 B

A 1 B

A 1 B

A 1 B

Heat Waves Increased Length of Average Heat Wave (days) 4 models and A 2 “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 A 2 Diffenbaugh et al. , 2005 Proceedings of the National Academy of Science

Increased Fraction of Extreme Precipitation A 2 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 gmgarfin@email. arizona. edu 520 -622 -9016 www. ispe. arizona. edu/climas http: //www. climate. noaa. gov/cpo_pa/risa/