Last update: 16 July 2011
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Extreme southwest droughts
CNAP researchers recently published an article in PNAS examining extreme droughts in the southwestern US. Using hydrologic model runs from downscaled global climate model simulations the group found the region is likely to become drier and experience more extreme droughts. During the historical period droughts ranged from 4 to 10 years but in the 21st century simulations some of the dry events persisted for 12 years or more.
Please click here for a personal-use copy of the full article. -
Attribution of Declining Western U.S. Snowpack to Human Effects
A detectable change in snowpack over the western United States cannot be fully explained by natural internal climate variability or the effects of solar and volcanic forcing. This recent study did not depend on geographic grouping or elevational banding. Approximately half of the observed changes in snowpack during the 1950-1999 period arose from climate responses to anthropogenic greenhouse gases, ozone and aerosols.
Please click here for a personal-use copy of the full article. -
California drought continues
As Blue Canyon heads into their dry season, precipitation runs a deficit of 24.4 inches -- 37% below normal. Most of California is facing the probability that this will be another dry year. Seven of the last ten years have seen water year (Oct to Sep) precipitation well below normal.
Click here to learn more about the continuing drought conditions. -
Changes in Aridity in the western United States
The West is relatively well-adapted to aridity. However during real droughts broad areas that are normally semi-arid or humid are subject to drier conditions. During droughts, the balance between waters that run off and those that evaporate back into the atmosphere are transformed temporarily. These changes color the entire region's water supplies and vegetation.
Please click here for the full drought report. -
The State of Bay-Delta Science 2008 -- Summary for Policymakers and the Public
This CALFED summary presents important new policy perspectives arising from recent advances in how scientists now understand the Bay-Delta ecosystem.
Please click here to learn more about CALFED and for a link to this summary.- or the full report -
This comprehensive report provides a basis for understanding many of the issues troubling the Delta, which is widely recognized as the weak link in California's water supply system and an ecosystem in freefall.
Please click here for the full CALFED report. -
Volunteers across the Nation to Track Climate Clues in Spring Flowers
Starting this week, citizen-scientist volunteers will be able to help track climate change by observing and recording the timing of flowers and foliage. Project BudBurst allows participants to enter their observations into an online database that, over time, will give researchers a more detailed picture of global climate change.
Please click here to learn more about Project BudBurst. -
Climate and floods still govern California levee breaks
The authors examined over a hundred years of levee break data for the Sacramento-San Joaquin River system. They discovered that the occurrence of breaks has been cyclic, as is precipitation here, and that those cycles had not substantially changed from the first part of the 20th Century to the more recent past (when most of the upstream control structures had been built).
(Click here for full article) -
California Warm and Dry - March 2007
March 2007 was warm and dry for the state of California. Preliminary reports place temperature 4.1 oF above normal and precipitation at 15.6% of normal. Statewide, the temperature was more like an average April and the precipitation was more like an average September. The Sierra region recorded the driest March since records began in 1895. Find more details in the California Climate Tracker. -
Mountain Views
The Newsletter of the Consortium for Integrated Climate Research in Western Mountains (CIRMOUNT) "Water Year 2006 -- Another 'Compressed' Spring in the Western United States?" (Dettinger, Pasteris, Cayan and Pagano) is one of the articles highlighted in the Jan 2007 CIRMOUNT newsletter. Click here for Jan 2007 edition -
Our Changing Climate: Assessing the Risks to California
The summary report of the Climate Scenarios Project has been released by CalEPA and CEC. Click above for a pdf of the report. The report is also available on the energy commission's website (www.energy.ca.gov) and on www.climatechoices.org. -
Trends in snowfall versus rainfall for the Western United States
A recent study published by Knowles, Dettinger and Cayan examines a 1949-2004 trend towards more winter precipitation falling as rain than snow. The above figure shows the fractional change in winter snowfall water equivalent after removing the effects of trends in precipitation over water years 1949-2004. Please click here or on the above image for the full article published in the 15 September 2006 issue of the Journal of Climate. - California's Wet Winter - 2005/06
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Climate science 2005: Major new discoveries
The World Resources Institute has selected peer-reviewed journal articles that show major climate science discoveries of 2005. 3 CAP/CCCC related articles were selected. - Snow in the mountains east of San Diego (March 14, 2006)
- Snow in the mountains east of San Diego (March 14, 2006)
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California Climate Scenario Model Page
Information for researchers working on the January 2006 Secretary report to the Governor and State Legislature -
Estimating Irrigation Water Use for California Agriculture: 1950s to
Present
Data are now available from simulations which model agricultural demand for irrigation water based on soil conditions, climate (daily min and max temp, daily precipitation, radiation), and general cropping systems. Three reference climate years (1983, 1996 and 1997) were used to simulate the range in climate conditions from the early 1950s through the early 2000s. - NOAA reports warmer 2005 for the United States
- Yosemite Valley Flooding and High Merced River Flow: 17 May 2005
- Weekly Snowpack and Drought Monitor Update Report
- NOAA/NCDC Summary of Storms in California and the Southwest from winter 2004/2005 Adventure
- Illilouette Adventure
- Wireless Hydrometeorological Sensors in Santa Margarita Ecological Reserve (SMER)
- Yosemite National Park Hydroclimate Monitoring
- Winter image of the California region
