in the News
Simulating the future water supply in California
Collaborative research involving Livermore scientists indicates that if concentrations of atmospheric carbon dioxide double from preindustrial levels, the resulting warming may dramatically change river flows in California. The simulations show that in a hypothetical El Niño season—a naturally occurring climate oscillation—state water managers may have to contend with an increased risk of both flooding and water shortages. For the simulations, researchers assumed that the strength of an El Niño event, as measured by increased sea-surface temperatures over long-term averages, would be the same in this warmer future as today. In California, an El Niño season typically brings more rain, which increases river flows and flood risk.
California’s water infrastructure is efficient at providing an adequate water supply and minimizing flood risk. The system, however, works well only in a climate that includes large amounts of mountain snow. Melting snow keeps reservoirs full in the late spring and summer, after rain and snowfall have stopped. Too much water falling in the rainy season causes flooding, but too little will decrease levels in the state’s reservoirs.
If winter temperatures warm because of carbon concentrations, more rain than snow will fall at higher elevations. In areas where snow does accumulate, it will melt sooner than it does in a normal year. These changes will result in higher river-flow rates during winter and lower rates during spring and summer, when flows normally are from snowmelt. In addition, if river-flow rates are too high during the winter, water managers will have to reduce reservoir levels to capture the increased winter flood surges. Those releases would further reduce the overall water supply for the entire year. The collaboration, which was led by professor Edwin Maurer from Santa Clara University, published its results in the January 27, 2006, issue of Geophysical Research Letters.
Contact: Philip Duffy (925) 422-3722 (firstname.lastname@example.org).
Demonstration checks readiness for biological attack
In January, researchers from Lawrence Livermore and Sandia national laboratories participated in a two-day demonstration at San Francisco International Airport to test the response and restoration protocols that would be undertaken following a biological attack. This demonstration was part of a three-year collaboration focused on shortening the time line for restoration after an illicit bioagent attack. Funded by the Department of Homeland Security, the Bio Restoration Demonstration Project included participants from several federal, state, and local agencies.
Livermore and Sandia researchers developed a restoration plan with templates that help airport personnel prepare for a biological terrorist attack. Using a mock scenario developed by an interagency team, participants implemented the plan to demonstrate how a facility could be quickly decontaminated and reopened.
Restoration plans include protocols to acquire samples after an attack, analyze the results, decontaminate affected areas, reopen facilities for public use, and if necessary, provide longer-term monitoring. To reduce the cleanup time after an attack, the Livermore–Sandia team also upgraded several technologies, including a Geographic Information System–based indoor sample tracking system, a rapid viability test procedure to determine within days whether anthrax spores are dead or alive, and sampling methodologies to better understand the percentage of anthrax spores collected in samples. As part of this project, the National Academy of Sciences is conducting a study to determine acceptable cleanup levels for anthrax, smallpox, and plague.
Contact: Ellen Raber (925) 422-3985 (email@example.com).
Volcanoes curbed rise in sea level
Simulations using 12 new climate models show that the 1883 eruption of the Krakatoa volcano in Indonesia substantially reduced ocean warming and sea-level rise during the 20th century. This study, which included researchers from Lawrence Livermore, the National Center for Atmospheric Research, the University of Reading in the United Kingdom, and the Hadley Centre for Climate Prediction and Research, examined the effects of volcanic eruptions on climate. The models include climate-forcing mechanisms such as changes in greenhouse gases, solar irradiance, and volcanic aerosols. The research team used each model to simulate the climate from 1880 to 2000 and compared the simulated data with available observations from that period.
Oceans expand and contract with changes in temperature. When the water is warmer, sea level increases; when cooler, it recedes. In recent decades, the volume average temperature of oceans (down to 300 meters) worldwide has warmed by about 0.037°C because of increased atmospheric greenhouse gases. Although seemingly small, this increase corresponds to a sea-level rise of several centimeters and does not include effects from such factors as melting glaciers.
The team’s results, which were published in the February 9, 2006, issue of Nature, indicate that the sea level would have risen much more had the Krakatoa eruption not occurred. Because volcanic aerosols scatter sunlight, an eruption typically causes the ocean surface temperature to cool, an anomaly that is gradually subducted into deeper layers where it persists for decades.
The research team also studied the 1991 Mount Pinatubo eruption in the Philippines, which was comparable to Krakatoa in terms of its size and intensity. Although similar ocean surface cooling resulted from both eruptions, the heat-content recovery occurred much more quickly after the Mount Pinatubo eruption. The observed warming of the upper ocean, which is primarily due to human influences, more than offsets the volcano’s effects.
Contact: Peter Gleckler (925) 422-7631 (firstname.lastname@example.org).