in the News
A New Code Simulates the
A Giant Leap for Space Telescopes
Checking Out the Hot Spots
in the News
further into climate change
Researchers at Livermore
have completed several studies to better understand climate change.
Evaluating energy technologies.
Late in 2002, Livermore researchers Ken Caldeira and L. John Perkins
collaborated with a team of international researchers to evaluate
a series of advanced energy technologies that do not emit carbon
dioxide or that limit its release to the atmosphere. The candidate
technologies include terrestrial, solar, and wind energy; solar-powered
satellites; biomass; nuclear fission; nuclear fusion; fission-fusion
hybrids; and fossil fuels from which carbon has been removed.
The researchers concluded
that current technologies are not helpful to stabilizing the climate.
Says Martin I. Hoffert of New York University, lead author of the
study report, . . . scientific innovation can only reverse
this trend if we adopt an aggressive, global strategy for developing
alternative fuel sources that can produce up to three times the
amount of power we use today. Currently, these technologies simply
dont existeither operationally or as pilot projects.
schemes. Using models that simulate the interaction between
global climate and land ecosystems, Livermore researchers have shown
that compensating for the carbon dioxide greenhouse effect by decreasinggeoengineeringthe
amount of sunlight reaching the planet could create a more vigorous
Bala Govindsasamy, Starley
Thompson, Philip Duffy, Ken Caldeira, and University of Wisconsin
collaborator Christine Delire published a report in the November
26, 2002, online edition of Geophysical Research Letters. They modeled
the effect of various schemes to reduce sunlight reaching Earths
surface and determined that the reduction would have little effect
on the terrestrial biosphere. In fact, says Caldeira,
turning down the Sun a bit reduces evaporation and therefore
gives plants more water for photosynthesis so that they may actually
grow better in a geoengineered world than they do today. However,
researchers strongly caution against adopting geoengineering interventions
because of the risks of system failure and unpredictable responses
from Earths climate system.
Measuring tropopause height.
Climate researchers have discovered another sign of human effects
on global climate. They have observed that the height of the tropopausethe
transition zone between the troposphere and the stratospherehas
increased, and those increases agree with projections made by climate
models of greenhouse warming. The warming affects atmospheric temperature,
which in turn affects tropopause height.
The observations and modeling
undercut claims that no warming has occurred during the last two
decades because satellite temperature measurements of the troposphere
have shown little or no warming. According to Livermore researcher
Benjamin Santer, Our best understanding is that this increase
[in tropopause height] is due to two factors: warming of the troposphere,
which is caused by increasing greenhouse gases, and cooling of the
stratosphere, which is mainly caused by depletion of stratospheric
ozone. Tropopause height changes give us independent evidence of
the reality of recent warming of the troposphere.
n addition to Santer, Livermore
scientists James Boyle, Krishna Achutarao, Charles Doutriaux, and
Karl Taylor teamed with researchers from the National Center for
Atmospheric Research, National Aeronautics and Space Administrations
Goddard Institute for Space Studies, Max Planck Institute for Meteorology,
and Institut für Physik der Atmosphäre in Germany to report
their findings in the online Journal
of Geophysical ResearchAtmosphere.
Contact: Ken Caldeira (925) 423-4191 (email@example.com)
or Benjamin Santer (952) 422-7638 (firstname.lastname@example.org).
for small objects beyond Neptune
At the winter meeting of
the American Astronomical Society in early January, a collaboration
of astronomers, including several from Lawrence Livermore, presented
their work to search for small, cometlike bodies in the outer solar
system with four half-meter telescopes.
In normal practice, astronomers
detect comet bodies by looking for the light reflected by them.
But the astronomers on the TaiwaneseAmerican Occultation Survey
(TAOS) Project will instead be searching for those rare moments
when one of the objects passes between telescopes and a nearby background
star. During one of these brief moments, scientists will be able
to study objects that are much too faint to be seen in reflected
sunlight, even with the largest telescopes.
TAOS is probing the Kuiper
Belt, known only through two objects (Pluto and its moon Charon)
until a flood of its bodies was discovered in the 1990s. Much about
the region remains unknown, but all theories about it predict that
there are many more small objects than large ones. TAOS scientists
believe that their technique will allow them to detect objects as
small as 3 kilometers in diameter. It is believed that there are
billions of objects this small in the outer solar system. The
TAOS survey will provide data on remnants of our early solar system
and early planet formation, says Livermore astronomer Kem
Cook. It will provide us insight into how the solar system
evolved. Well be looking at the smallest objects that anyone
The collaboration is made
up of scientists from the Institute of Astronomy and Astrophysics
in Taiwan, University of Pennsylvania, National Central University
in Taiwan, Yonsei University in South Korea, and National Aeronautics
and Space Administration as well as Livermore.
Contact: Kem Cook (925) 423-4634 (email@example.com).
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