Climate Change and Water Supply Research Drought Response Workshop October 8, 2013 DWR Photo Oroville Reservoir, 2009
Talk Overview Expectations History Atmospheric Rivers and Water Supply Current Research Next Steps
Slide from Jamie Anderson DWR- Bay Delta Ecosystem Changes
Year to Year Precipitation Variability Std Dev of Annual Precipitation Mean Annual Precipitation California precipitation is uniquely variable Dettinger et al, 2011
Storms and California Water Supply Just a few storms each year are the core of California s water supplies Dettinger et al, 2011
Precipitation (Inches) Northern Sierra 8 Station Index 100 90 80 70 60 50 40 30 20 10 0 1921 1931 1941 1951 1961 1971 1981 1991 2001 Monthly precipitation, Water Year inches Annual Average: 50 inches Maximum Year (1983): 88.5 inches Minimum Year (1924): 17.1 inches Period of Record 1921- Present Average of: Mt. Shasta City Shasta Dam Mineral Brush Creek RS Quincy Sierraville RS Pacific House Blue Canyon
Northern Sierra 8 Station Index 10 8 6 Lower elevation mountains 4 2 0 Oct Nov Dec Jan Feb Mar Apr May Jun Monthly precipitation, inches Jul Aug Sep DJF Average: 27 inches Maximum Month (Dec. 1955): 30.83 inches Minimum Month (45 instances): 0 inches Period of Record 1921- Present Average of: Mt. Shasta City Shasta Dam Mineral Brush Creek RS Quincy Sierraville RS Pacific House Blue Canyon
21 st Century Breakdown So Far 8 Station Index 12 10 8 6 4 2 0 Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Period of Record 1971-2000
21 st Century Breakdown So Far 8 Station Index 12 10 POR Average: 50 inches 1971-2000: 53 inches 21 st Century: 50 inches 8 6 4 2 0 Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Period of Record 1971-2000 21st Century
Sacramento River Runoff Distributions (Million Acre-Feet) 8 7 6 5 4 3 2 1 0 Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep Period of Record 1971-2000 21st Century
Decadal Scale Variability 70 60 50 40 30 20 10 0 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 Los Angeles County Sonoma Mendocino 8 Station Index 5 Station Index
Decadal Scale Variability 8 Station Index 12 10 8 6 4 2 0 Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep POR PDO+ PDO-
Storms and California Water Supply Just a few storms each year are the core of California s water supplies Dettinger et al, 2011
Key Phenomena Affecting California Water Supply/Flooding: Storm Track changes Cyclogensis L Flooding & water supply MJO/Tropical Convection Easterly Wave ENSO CA storms are a product of the alignment of several key processes operating at multiple space and time scales Slide adapted from M. Ralph
The Storm of 4-5 Jan 2008 L 32 ft waves Atmospheric river GOES IR image of major West Coast storm Time = 0030 UTC 5 January 2008 Low pressure center is off WA coast 6-10 ft snow 7-13 in rain Note that major impacts were focused >500 miles south of the Low pressure center in this storm. Many major impacts are associated with the landfall of the atmospheric river element of the storm, the precise characteristics of which have not been operationally monitored offshore or onshore. Slide from M. Ralph
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2013 Example ARE 1: 15.5 inches in 8 days (33% of WY total) ARE 1 ARE 2 ARE 2: 6 inches SWE in 5 days (32% of WY total)
LARGEST 3-DAY PRECIPITATION TOTALS, 1950-2008 Primarily due to Atmospheric River events Ralph, F. M., and M. D. Dettinger, 2012: Historical and national perspectives on extreme West Coast precipitation associated with atmospheric rivers during December 2010. Bull. Amer. Meteor. Soc., 93, 783-790.
Current Research Advancements in monitoring atmospheric river conditions and tracking change Exploring role of remote sensing for monitoring Begun exploring characteristics of past, present, and future atmospheric rivers Begun exploration of decadal variability and change
Next Steps Targeted opportunities in monitoring Develop tools and indicators to track change and facilitate planning efforts Improve understanding of variability across time scales Increase understanding of physical processes to improve capacity execute integrated water management in a changing climate
Questions? Email: Michael.L.Anderson@water.ca.gov