Scientists from the University of Iowa (UI), in the US, have created a technique to help weather monitoring satellites "see" through the clouds, and better estimate the concentration of pollutants, such as soot.
The finding is important, because, like GPS systems, clouds block remote-sensing satellites' ability to detect, and thus calculate, the concentration of pollution nearer to the ground. This includes particles (commonly known as soot) that reduce air quality and affect weather and climate.
The results of the study are published in the online edition of the journal Proceedings of the National Academy of Sciences (PNAS).
“Particles in the atmosphere (aerosols) interact with clouds, changing their properties. With this technique, we can use remote sensing observations from satellites to estimate these cloud properties in order to correct predictions of particle concentrations. This is possible due to a numerical model that describes these aerosol-clouds interactions,” said Pablo Saide, environmental engineering doctoral student and researcher at the UI Center for Global and Regional Research (CGRER).
Scott Spak, co-author and assistant professor of civil and environmental engineering in the UI College of Engineering, added that the new technique is expected to find immediate application across a wide range of activities. Examples include: air quality forecasting, numerical weather prediction, climate projections, oceanic and anthropogenic emissions estimation, and health effects studies.
But the ability to see pollution through the clouds is also expected to have on the ground health results.
“Unlike previous methods, this technique can directly improve predictions of near-surface, fine-mode aerosols—such as coal-fired electric generating plants and wood-fuelled cooking fires—responsible for human health impacts and low-cloud radiative forcing (solar heating),” said Greg Carmichael, co-author, professor of chemical and biochemical engineering, and CGRER co-director. "This technique is also complementary to previous methods used, allowing the observing system to ‘see aerosols’ even under cloudy conditions.”
The researchers conducted their study using National Science Foundation (NSF) aircraft measurements to make simultaneous cloud and particle observations, which verified satellite observations and the mathematical formulas used to determine the pollution concentrations in the air. The research was funded by NSF and NASA.