Researchers Improve Satellite Surface Measurements

Newswise — University of Iowa assistant professor Scott Spak and students participating in a six-week NASA summer program have found that taking into account local atmospheric conditions can improve the accuracy of satellite surface imagery.

The results of their study from the 2009 NASA Student Airborne Research Program are published in the Aug. 4 online edition of the journal Remote Sensing Letters, (http://www.tandfonline.com/doi/abs/10.1080/01431161.2010.551550).

In brief, the students from Howard University and Georgia Institute of Technology flew over Southern California aboard NASA's DC-8 airborne science laboratory and operated NASA's MODIS and ASTER remote sensing instruments. The flight was guided by forecasts from the UI Center for Global and Regional Environmental Research (CGRER).

When processing the images they collected, the students found that using CGRER's regional model forecasts for local weather and air quality substantially improved sea surface temperature measurements and also increased the sensitivity of measurements over cities and areas covered by vegetation.

Using CGRER model results was found to be an improvement over standard approaches to calculating surface measurements from satellite images, which incorporate a one-size-fits-all average for weather and trace gas concentrations.

"This new approach can help improve the global satellite record of the Earth's surface and oceans, by taking better daily snapshots of how human activity affects them over time," Spak said. "This one change can improve our ability to accurately track a wide range of environmental questions, including urban heat islands, coastal algae blooms and the regrowth of deforested areas."

Spak and CGRER Co-director Greg Carmichael are working with NASA to apply the technique to improve satellite air pollution estimates.

Spak is an assistant professor with joint appointments in the UI Public Policy Center, School of Urban and Regional Planning, and the UI College of Engineering Department of Civil and Environmental Engineering.

STORY SOURCE: University of Iowa News Services, 300 Plaza Centre One, Suite 371, Iowa City, Iowa 52242-2500