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February 2005

shorttakes

An overview of projects throughout the organization

Winter roads

Keep an eye out for five weather stations along E-470 this winter. The stations work in conjunction with the Maintenance Decision Support System (MDSS), a groundbreaking software system that was developed by RAL with support from colleagues at several other institutions. The program will help road managers keep roads as safe as possible when winter weather hits.

Bill Mahoney (RAL) and staff have been working on the MDSS since 1999. After testing the system in Iowa for two years, they are evaluating it on E-470 and other highways in Colorado. Sponsored by the Federal Highway Administration, the MDSS promises to save lives, cut costs, and keep drivers on the move. The program works by integrating real-time information from weather forecasts and surface weather and road condition measurements, and analyzing the information in different ways to predict road conditions. Road crews receive expected pavement temperatures, humidity, precipitation amounts and types, and wind speeds for short segments of roads, followed by recommendations for when and where to plow and use anti-icing chemicals.

The E-470 Public Highway Authority asked to be involved in testing the MDSS after it learned about the new software program. Commercial weather service providers are currently working with several state departments of transportation in the upper Midwest to implement the program, and weather service providers in Canada and northern Europe have expressed interest as well.

Antarctica forecasts

Staffers in MMM and SCD who work on weather forecasts for Antarctica acquired a new supercomputer in January that will help them produce faster, better forecasts for the remote continent.

The computer, an IBM e1350 nicknamed “pegasus,” runs faster and has more capacity than the current system, a Compaq ES40 cluster. It has a peak computational capability of nearly 600 billion calculations per second, with more than 270 gigabytes of memory and 3 terabytes of disk capacity.

Scientists will use the Mesa Lab-based computer to run the Antarctic Mesoscale Prediction System (AMPS), which makes twice-daily weather forecasts for Antarctica. The forecasts are important for researchers on the continent and are critical during rescue operations.

The computer’s speed and capacity will allow AMPS project leader Jordan Powers and scientist Kevin Manning, both from MMM, to run the forecasting program at higher resolution and produce forecasts more quickly. They plan to boost the resolution for even the most remote areas of Antarctica to 20 kilometers (12 miles) so that the model can capture small-scale cloud systems and other atmospheric events. They also intend to incorporate NCAR’s newest forecasting system, the Weather Research and Forecasting (WRF) model, into AMPS.

Increased drought

A new analysis by CGD’s Aiguo Dai, Kevin Trenberth, and Taotao Qian has found that the percentage of Earth’s land area stricken by serious drought more than doubled from the 1970s to the early 2000s. Rising global temperatures appear to be a major factor.

The team, which looked at a variety of long-term records of temperature and precipitation, found that the fraction of global land experiencing very dry conditions (defined as -3 or less on the Palmer Drought Severity Index) rose from about 10–15% in the early 1970s to about 30% by 2002. By factoring out rainfall and snowfall, the scientists estimated that almost half of the drought increase was due to rising temperatures rather than decreases in precipitation.

Palmer Drought Severity

This depiction of linear trends in the Palmer Drought Severity Index from 1948 to 2002 shows drying (reds and pinks) across much of Canada, Europe, Asia, and Africa and moistening (green) across parts of the United States, Argentina, Scandinavia, and western Australia. (Illustration courtesy Aiguo Dai and the American Meteorological Society.)

The Palmer index results are consistent with simulations using a comprehensive land surface model.

Aiguo presented the new findings at the American Meteorological Society’s annual meeting last month. The research also appeared in the December issue of the Journal of Hydrometeorology.

Permian extinction

One of the great mysteries of paleontology is the Permian extinction of about 251 million years ago. Scientists have speculated that as many as 96% of Earth’s marine species may have disappeared, along with about three-quarters of terrestrial species—but they don’t know the cause.

CGD’s Jeff Kiehl and Christine Shields are working to shed light on the Permian extinction by simulating its climate. Using the paleoclimate component of the Community Climate System Model, version 3, they are studying how the period’s sharply rising levels of atmospheric carbon dioxide and massive volcanic eruptions may have affected global temperatures, oceanic currents, and other phenomena.

The modeling presents unique challenges because of limited data and significant geographic differences between the Permian and present-day Earth. Jeff and Christine have had to estimate, for example, how thermohaline circulation (the movement of heat and salinity in the oceans) may have differed at a time when all the continents were consolidated into the giant land mass known as Pangaea. Over the next year, in collaboration with Jean-Francois Lamarque (ACD), they hope to incorporate additional features into the model, including concentrations of sulfates and other chemicals in the atmosphere.

CCSM

This image, from a CCSM simulation, shows annual mean surface temperatures at the time of the Permian extinction about 251 million years ago. (Illustration courtesy Jeff Kiehl.)


Also in this issue...

An eye on Washington

ISSE reflections on the tsunami

Random profile: Shu-Peng “Ben” Ho

NCAR to survey scientists, engineers


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