Satellite-Enhanced Dust Forecasts Aid Public Health Managers

NASA's Public Health Applications in Remote Sensing project, or PHAiRS, has just released its report on the study. Led by investigators Stanley Morain of the University of New Mexico in Albuquerque, and William Sprigg of the University of Arizona-Tucson, scientists evaluated the influence of space-based observations on predictions of dust storms.

Using NASA satellite data, forecasters could more accurately predict the timing of two out of three dust events in Arizona, California, New Mexico, and Texas. This forecasting capability is the first step toward a reporting system that health officials could use to warn at-risk populations of health threats and respond quickly to dust-related epidemics.

"The program has been successful in its work to improve dust storms predictions, which has important implications for air quality and respiratory distress warnings," said John Haynes, PHAiRS program manager at NASA Headquarters in Washington.

Dust and the pathogens it carries have been blamed for worsening some cardiovascular and respiratory diseases, including asthma.

Now, public health professionals have been enlisted to work with the PHAiRS team to assess the model's real-world utility. The team is collaborating with physicians, public health experts and community leaders in Lubbock, Texas, to integrate the NASA dust storm predictions into a computer-based decision-support system called the Syndrome Reporting Information System, which maps reported cases of respiratory distress.

The satellite-enhanced system would allow health and environmental managers to view the next 48 hours of dust concentrations for their areas and track the number of respiratory distress situations that result.

Ultimately, the system could allow health officials to issue early warnings to populations at risk for dust-related health complications. Preliminary feedback from public health end-users about the enhanced system's performance is expected in January 2009.

The same weather system that brought snow and ice to the American Midwest just after Thanksgiving 2005 kicked up dust in western Texas and eastern Mexico. The winds fanned the flames of grass fires, adding smoke to the mixture. An instrument flying onboard NASA's Aqua satellite captured this image on November 27, 2005.

NASA launched PHAiRS in 2004 to identify how satellites could help modeling and forecasting of dust storms and to enhance a computer-based system that health managers can use to report and respond to dust-related health symptoms.

The key to better dust forecasts is to represent accurately the features that influence the behavior of dust - land topography, the proportion of land to water, and surface roughness.

Information in previous models about a region's features was patched together from old maps and topographic surveys, which do not accurately represent seasonal or cyclical changes in vegetation and related surface features.

"Dust modeling always has relied on surface characteristics that we knew were wrong," Sprigg said.

Through PHAiRS, up-to-date measurements of Earth's surface features collected from instruments on NASA's Terra and Aqua satellites provided the critical details needed to enhance an existing dust model.

Observations of Earth from space offer more complete information, filling in the gaps between the locations of surface measurements and providing up-to-date snapshots of changing surface features.

The team began with an existing model developed by Slobodan Nickovic of the World Meteorological Organization in Geneva that describes how dust is lifted off the ground and carried in the atmosphere.

Researchers coupled this model with an operational weather forecast model the U.S. National Weather Service created. The team adapted the model to accommodate dust storms in the U.S. Southwest and then introduced the new satellite-derived measurements.

After using the new model to make hourly dust forecasts for California, Arizona, New Mexico, and Texas during dust events, the team compared their results to real-world observations. They found that the NASA data improved the model estimates of wind speed, direction, near-surface temperature, and the location and amount of dust lifted off the ground.

Statistics for the model's performance show that between January and April 2007, the timing of two out of three dust storms in Phoenix could be forecasted precisely.

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