california climate change: a historical...
TRANSCRIPT
California Climate Change:California Climate Change:A Historical Perspective A Historical Perspective
Michael Anderson, Ph.D., P.E.Michael Anderson, Ph.D., P.E.California Department of Water ResourcesCalifornia Department of Water Resources
Division of Flood ManagementDivision of Flood Management
CH1 IntroductionCH1 IntroductionCH2 BackgroundCH2 BackgroundCH3 DWR StudiesCH3 DWR StudiesCH4 SWPCH4 SWP--CVP ImpactsCVP ImpactsCH5 Delta ImpactsCH5 Delta ImpactsCH6 Flood ManagementCH6 Flood ManagementCH7 EvapotranspirationCH7 EvapotranspirationCH8 Future DirectionsCH8 Future Directions
Peer reviewed chaptersPeer reviewed chapters
AcknowledgmentsAcknowledgments
Thanks to Jim Goodridge retired state Thanks to Jim Goodridge retired state climatologist, David Rizzardo, Matt climatologist, David Rizzardo, Matt Winston, Boone Lek, BG Heiland, Tawnly Winston, Boone Lek, BG Heiland, Tawnly Pranger, Aaron Miller, Maury Roos, John Pranger, Aaron Miller, Maury Roos, John King, and Steve Nemeth of DWRKing, and Steve Nemeth of DWR--DFM DFM and Jamie Anderson of DWR Delta and Jamie Anderson of DWR Delta Modeling.Modeling.
Presentation OutlinePresentation Outline•• Introduction Introduction
•• Historical Data Historical Data
•• Climate ChangeClimate Change
•• Impacts AssessmentImpacts Assessment
IntroductionIntroduction
•• Climate vs. Weather Climate vs. Weather –– ““Climate is what Climate is what you expect and weather is what you getyou expect and weather is what you get””Mark TwainMark Twain
•• Global Climate Models aim to predict Global Climate Models aim to predict climate not weatherclimate not weather
•• Individual weather events may vary greatly Individual weather events may vary greatly for a given climatefor a given climate
IntroductionIntroduction•• Looking back to frame a look aheadLooking back to frame a look ahead•• Examine historical record for Examine historical record for
trends and variabilitytrends and variability–– TemperatureTemperature–– PrecipitationPrecipitation–– RunoffRunoff–– Flood PeaksFlood Peaks–– Sea Level RiseSea Level Rise
•• How does variability compare to trends?How does variability compare to trends?
Historical TemperatureHistorical Temperature•• Statewide average observed warming of about 0.5 Statewide average observed warming of about 0.5 °°C (1 C (1 °°F)F)
40
50
60
70
80
1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000
Tem
pera
ture
(deg
F)
Maximum Average Minimum
Historical PrecipitationHistorical Precipitation
•• Statewide Average Precipitation: Lots of variability, no trendStatewide Average Precipitation: Lots of variability, no trend
0
10
20
30
40
50
1890 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000
Year
Prec
ipita
tion
(inch
es)
1915-1935:20.8 inches
1980-2000:25.6 inches
1890-2000:23.9 inches
Historical Runoff TimingHistorical Runoff Timing
Sacramento River System
Water Year Runoff
0
8,000
16,000
24,000
32,000
40,000
1901 1911 1921 1931 1941 1951 1961 1971 1981 1991 2001
Water Year (October 1 - September 30)
Run
off V
olum
e (tA
F)
Historical Runoff TimingHistorical Runoff Timing
April-July Runoff
0
2,000
4,000
6,000
8,000
10,000
12,000
14,000
16,000
1901 1911 1921 1931 1941 1951 1961 1971 1981 1991 2001
Water Year (October 1 - September 30)
Run
off V
olum
e (tA
F)
Sacramento River System
Historical Runoff TimingHistorical Runoff TimingSan Joaquin River System
Water Year
02,0004,0006,0008,000
10,00012,00014,00016,000
1901 1911 1921 1931 1941 1951 1961 1971 1981 1991 2001
Water Year (October 1 - September 30)
Run
off V
olum
e (tA
F)
Historical Runoff TimingHistorical Runoff TimingSan Joaquin River System
April - July Runoff
0
2000
4000
6000
8000
10000
1901 1911 1921 1931 1941 1951 1961 1971 1981 1991 2001
Water Year (October 1 - September 30)
Run
off V
olum
e (tA
F)
Changes in Annual Peak RunoffChanges in Annual Peak Runoff
165/489165/48952/9152/91145/232145/232RangeRange
48/8448/8411/1911/1933/5033/50Standard Standard DeviationDeviation
93/12393/12312/1712/1742/5242/52MeanMean
EelEelTuolumneTuolumneFeatherFeatherPre/Post Pre/Post 19551955
Values in 1000 cfs for annual peaks of 3-day average flows1904-2004 data used for analysisRange is maximum-minimum values for time period
Sea Level RiseSea Level Rise
Golden Gate
Golden Gate
A look aheadA look ahead……
Climate change model information Climate change model information from Global Climate Modelsfrom Global Climate Models
Projected Changes TemperatureProjected Changes Temperature
From Dettinger, 2005Some Uncertainty
Projected Changes PrecipitationProjected Changes Precipitation
From Dettinger, 2005Lots of Uncertainty !
Impacts Assessment Impacts Assessment -- HydrologyHydrology
•• Examine possible impacts of increases in mean Examine possible impacts of increases in mean atmospheric temperature of 1atmospheric temperature of 1--55°° CC
•• Assume Assume snowpacksnowpack retreats at 500 feet per 1retreats at 500 feet per 1°° CC
2030405060708090
100
0 1 2 3 4 5
Avg. Atm. Temp. Increase ( C)
Perc
ent S
now
Fre
e
Above Shasta Above Oroville Above Folsom
Snowpack Reduction ImpactsSnowpack Reduction Impacts
Storm Runoff Impacts Storm Runoff Impacts •• Higher snow levels yield more direct runoff per stormHigher snow levels yield more direct runoff per storm
0.0
0.5
1.01.5
2.0
2.5
0 12 24 36 48 60 72 84 96 108
120
132
144
Hour
Scal
ed R
unof
f
Base Case 1 degree increase3 degree increase 5 degree increase
Impacts AssessmentsImpacts Assessments•• Initial AssessmentsInitial Assessments
–– CVP/SWP Operations CVP/SWP Operations –– Dan Easton (DWR)Dan Easton (DWR)
–– Delta Issues Delta Issues –– Jamie Anderson (DWR)Jamie Anderson (DWR)
•• Ensemble Methods Ensemble Methods –– The next stepThe next step–– CVP/SWP Operations Impacts with Ensemble CVP/SWP Operations Impacts with Ensemble
Analysis Analysis –– Levi Brekke (USBR)Levi Brekke (USBR)
–– Weighted Estimation of Projection Weighted Estimation of Projection Distributions Distributions –– Levi Brekke (USBR)Levi Brekke (USBR)
Questions ?
Web Page: Web Page: http://http://www.climate.water.ca.govwww.climate.water.ca.govEmail: Email: [email protected]@water.ca.gov