Editors: Please note two other PECASE Awards were received by CU engineering faculty, described in an accompanying release.
Boulder researchers Steven S. Brown and Thomas M. Hamill have been named winners of Presidential Early Career Awards for Scientists and Engineers.
Both scientists are research associates at the Cooperative Institute for Research in Environmental Sciences and both work at NOAA's David Skaggs Research Center. CIRES is a joint institute of the University of Colorado at Boulder and the National Oceanic and Atmospheric Administration.
Established by the Clinton administration in 1996, the award is the highest honor bestowed by the U. S. government on outstanding scientists and engineers beginning independent careers. Eight federal departments and agencies submit nominations for the prizes.
The awards will be presented in Washington, D.C., at a date to be announced by the White House. Each award entails a research allowance of $50,000 per year to be administered over five years.
Brown, of the NOAA Aeronomy Laboratory, was cited for developing a technique and an instrument to measure elusive atmospheric chemicals. The chemicals include some that influence the stratospheric ozone layer and the production of ozone pollution in the lower atmosphere.
Brown holds a doctorate in chemistry from the University of Wisconsin. His research adapted a method invented in 1988, called "cavity ring-down spectroscopy." The new application involves measuring concentrations of trace atmospheric species such as nitrate radicals (NO3).
"Cavity ring-down spectroscopy is a simple idea," Brown said. "We measure the time decay of a laser-generated light pulse as the pulse bounces back and forth in a chamber containing the gas we want to measure."
Historically the measurement of NO3 has been a difficult problem because the gas is present in the atmosphere only in trace amounts -- often less than 1 molecule of NO3 per trillion molecules of air -- and only in the dark. Highly unstable and reactive, nitrate radicals are produced by burning fossil fuels but also occur naturally in the atmosphere.
Capitalizing on NO3's natural light-absorbency, Brown's instrument measures the time it takes for laser light to leak from a tube-shaped optical cavity formed between two highly reflective mirrors. The time varies depending on the concentration of NO3 inside the cavity.
Brown's technique will allow scientists to better assess how ozone production is influenced by nitrogen oxides in the atmosphere.
Hamill, a meteorologist with the NOAA-CIRES Climate Diagnostics Center, was recognized for research in understanding what causes errors in weather forecasts.
With a doctorate in atmospheric science from Cornell University, Hamill studies a technique called ensemble weather forecasting. Used since about 1992 in the United States and Europe, ensemble forecasting involves using computers to generate multiple weather forecasts. This technique is useful for estimating the uncertainty of forecasts.
Hamill's research focuses on new ways of making parallel forecasts and ways to assimilate the forecast information to make weather probabilities more accurate.
"Our work tries to put error bars on forecasts." Hamill said. "Using a probability forecast, a power supplier trying to determine the likelihood of a cold snap ahead can better estimate the need for resources. It translates into real costs savings."
Headquartered at CU-Boulder, CIRES is the largest and oldest of the 11 joint institutes established with universities by NOAA. CIRES faculty, researchers and students study Earth's oceans, the Great Lakes, inland waters, arctic regions, the solar terrestrial environment, the intermountain West and the atmosphere.
CIRES involves eight CU departments and several NOAA labs in research focused on environmental chemistry and biology, atmospheric and climate dynamics, cryospheric and polar processes and the solar-terrestrial environment.