climate change, arkstorms & the sierra nevada
DESCRIPTION
Climate Change, ARkStorms & the Sierra Nevada. Mike Dettinger, US Geological Survey, Scripps Institution of Oceanography Dale Cox, US Geological Survey, Sacramento. NOAA’s California-Nevada Applications Program. PROJECTED TEMPERATURE CHANGES. PROJECTED CHANGES IN ANNUAL TEMPERATURES, - PowerPoint PPT PresentationTRANSCRIPT
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Climate Change, ARkStorms & the Sierra NevadaMike Dettinger, US Geological Survey, Scripps
Institution of OceanographyDale Cox, US Geological Survey, Sacramento
NOAA’s California-Nevada Applications Program
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Dettinger, SFEWS, 2005
PROJECTED CHANGES IN ANNUAL TEMPERATURES, NORTHERN SIERRA NEVADA
PROJECTED TEMPERATURE CHANGES
-4F20 of 23 in this range
0F
+4F
+8F
12F
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All Drier All Wetter
Among 12 projections with high-CO2 emissions, how many models yield increasing (decreasing) precipitation?
PROJECTED PRECIPITATION CHANGES
Northern California still on the edge between more-or-less precipitation.
Percentage Change from Historical Normals
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PROJECTED SNOWCHANGES
Courtesy of David Pierce, SIO
End snow szns
(9 CMIP5 RCP4.5 GCMs BCCA downscaled, VIC snow simulated)
Rain vs Snow
More changeNO change
Start snow szns
Dettinger & Culbertson, SFEWS 2008
• More rain vs snow
• Shorter snow-cover seasons
• Earlier snowmelt & runoff
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Cayan et al., SWCA, 2013
16 models, A2 emissions
Northern Sierra Nevada
Median of A2 emissionsMedian of B1 emissions
Center of sliding 50-yr window
Per
cent
age
of
hist
oric
al 5
0-yr
floo
d
Das et al., ClimChg, 2012; JH, in rev
PROJECTED STREAMFLOW CHANGES
Distributions of 50-yr flood changes
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PROJECTIONS of MONSOONS/FIRE-WEATHER
June-September, 2041-69 vs 1971-99Precipitation Temperature
June-October, 2080-99 vs 1980-99Moist Static Energy
• Reductions in summer precipitation? (Mearns et al. 2009)
• Later monsoon arrivals & withdrawals (Cook & Seager, 2013)
• More stable atmosphere, less thunderstorming (Cook & Seager, 2013)
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50-yr FloodsPROJECTIONS of LARGEST WINTER STORMS (Atmospheric rivers, or pineapple expresses)
Update to Dettinger, JAWRA, 2011
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Short-Term (during & immediately following storm)• Flooding along streams & in meadows• Wind damage to structures• Deep wet snows/traffic interruptions, around Lake &
to/from Lake• Infrastructure damages/utility interruptions• Trashed snow runs
• Erosion, sediment & nutrient transports into Lake• Wind-blown tree falls• Dilution of upper layer of Lake?
“ARkStorm” Consequences at Lake Tahoe
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Long-Term (month to years following storm)• Deep wet snows / continuing traffic interruptions to/from
Lake (e.g., 1986)• Continuing utility interruptions• Trashed snow runs• Expensive repairs & economic recoveries
• Forest/meadow damages• Continuing erosion/nutrient episodes• Major Lake clarity impact?• Repeated Lake clarity impacts?• Open-doors for invaders?
“ARkStorm” Consequences at Lake Tahoe
Emergency-Response Desktop Exercises coming to Tahoe/Reno/CC region, Winter 2014!
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FROM CLIMATE/HYDRO MODELS & OTHER CONSIDERATIONS, WE PROJECT:• Warming by +3 to +6ºC across Sierra, likely more so at higher altitudes
• Much of Sierra in range for modest, wetter-or-drier trends
•Monsoons may be delayed/reduced
• Extreme weather/floods gets more extreme
More rain, less snow
Less snowpack
Increased winter flood risks but longer low flows
Less overall streamflow (think -5 to -15%)
Changes in aquifer recharge
Longer growing seasons
More, more severe heat waves
Fewer (but deeper?) cold snaps
Increased wildfires
Favors many invasive species
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For much more info on these & other topics, see the new 2013 Southwest Climate Assessment Report:
http://www.swcarr.arizona.edu
Contact [email protected] w/questions or for info re: ARkStorm@Tahoe