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April 2003

The Laboratory
in the News

Commentary by
C. K. Chou

Finding the Missing Piece in the Climate Change Puzzle

An Elusive Transformation—The Mystery of Oscillating Neutrinos

Toward a Common Data Model for Supercomputing

Into the Vortex—New Insights into the Behavior of Dynamic Fluids




C. K. Chou

C. K. Chou
Associate Director for Energy and Environment

Aerosols and the Global Climate Puzzle

LAWRENCE Livermore has long been among the leaders in using the most powerful computers available to simulate the global changes in climate. As described in the article entitled Finding the Missing Piece in the Global Climate Puzzle, a key factor in global climate change is aerosols, which are microscopic particles suspended in the clear sky and in clouds. Increasingly, scientists are studying aerosols to help explain our complex climate patterns. The most recent Livermore simulations show that rising concentrations of aerosols in the atmosphere may be cooling the planet and thus partially counteracting the effects from the steady accumulation of greenhouse gases.
The Laboratory’s first aerosol simulations date back to the late 1980s, when researchers conducted studies of so-called nuclear winter. These studies simulated the climatic effects of large injections of smoke particles high into the atmosphere, which would likely follow a large-scale nuclear war.
Every day, different aerosols enter the atmosphere through natural processes, including dust storms and sea salt spray. Many other kinds, however, are produced by human activities such as the burning of fossil fuels and biomass. Understanding the geographic distribution of aerosols produced by human activities and their distribution within the atmosphere by particle size is crucial to understanding climate change.
The Department of Energy is interested in aerosols because of their effects on climate. Their influence on clouds is especially significant, which is why cloud–aerosol interplay is an important aspect of DOE-sponsored climate change research.
DOE also sponsors aerosol research because regulators must keep aerosols in mind when formulating energy policy. For example, regulators have placed restrictions on diesel emissions because they produce aerosols that, in high concentrations, can be harmful to people. In this respect, aerosols are important to air quality and human health. Aerosols composed of small particles, such as soot and sulfur dioxide, can lodge deep within our lungs and cause respiratory ailments.
Some forms of aerosols may also be involved in the carbon cycle and the ocean's ability to absorb carbon. The carbon cycle is the flow of carbon compounds between the biosphere, atmosphere, and oceans. When dust aerosols containing iron, for example, are deposited in the ocean, this iron can help accelerate natural oceanic processes that take up carbon from the atmosphere.
An important mission of the Energy and Environment Directorate is studying the link between energy production (and the fuels used in this production) and the resulting environmental consequences. Aerosols play an important role linking such diverse processes as energy production, air quality, atmospheric chemistry, climate change, human health, and possibly, the carbon cycle.
Simulating these processes, many of which are incompletely understood, and validating the simulation results require enormous amounts of data and the most powerful supercomputers. The Laboratory has long excelled in using supercomputers for understanding complex physical systems. Livermore’s Energy and Environment Directorate is applying its modeling expertise and Lawrence Livermore’s computing platforms to further understanding of aerosols and their relationship to energy, the environment, and human health.

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UCRL-52000-03-4 | April 16, 2003