Dr. Hans Moosmüller is busy, always thinking about his next invention. This is evident as he currently holds five patents and has four more pending. His most recent patent offers a simple way to help quantify the aerosol contribution to climate change. “Adding aerosols to the atmosphere changes the ‘whiteness’ of the earth as a whole and thereby the amount of solar energy retained by the earth; comparable to wearing a white or black shirt on a sunny day—cooling with a white shirt, heating with a black shirt,” Moosmüller said.
To determine the whiteness, or albedo, of aerosols, one needs to measure aerosol scattering and absorption coefficients. Moosmüller already holds a number of patents for the measurement of these coefficients; however, in addition to the amount of light scattered by aerosols, the direction of the scattering is also of importance. For example, incoming sunlight that is backscattered into space contributes to cooling, while near forward scattering of sunlight does not change the earth’s temperature. In the radiative transfer component of climate models, the direction of aerosol scattering is expressed in a single number, the asymmetry parameter, which is -1 for pure backscattering, 0 for symmetric scattering, and +1 for pure forward scattering. While this parameter is an important part of modeling climate change, so far no instruments exist to measure it.
“In order for climate change modeling to work, you need to have accurate measurements,” said Moosmüller.
This is where Moosmüller’s most recent patent comes in, which describes a simple method and apparatus to measure the aerosol asymmetry parameter. He and his graduate students from the University of Nevada, Reno are currently working on building the instrumentation that is needed to measure this important aspect of aerosol light scattering.